Mythical mermaids are often known for their fishy tails and alluring songs. But if you were underwater with one, her tunes wouldnt sound quite like they do in the movies. And you might struggle to understand the words as Ariel or her other mermaid friends burst out singing.



Even next to a mermaid, the song would sound muffled and would seem to come from all around, says Jasleen Singh. You could still make out what she is saying, but it would sound fuller with less clarity, Singh says. She studies human hearing at Northwestern University in Evanston, Ill.





If mermaids existed, and if they sang and talked to one another, their hearing and sound-making setups might resemble marine creatures features instead of humans. To understand why, you have to start with the basics of sound and hearing.



Explainer: How the ears work



Sound is produced when an object vibrates. Touch your throat while you talk, and you can feel your vocal cords vibrating inside your neck. These vibrations can travel through gases, liquids and solids. In each medium, atoms and molecules get pushed around by a sound sources back-and-forth motion. These particles bump into each other in a rippling pattern of waves. Like a line of falling dominoes, the colliding particles spread sound.



Human hearing starts with sound waves entering the air-filled space in each earhole. The waves vibrate the eardrum, which wiggles three little ear bones. One of the bones taps on a snail-shaped structure in the inner ear called the cochlea. This fluid-filled structure converts the vibrations into electrical signals that the brain understands as sound.



Underwater, its a different story. Since water plugs your ears, you rely on sound waves directly vibrating the skull. This happens on land too, but it works better below the waters surface. Thats because water and bone have similar densities. When sound waves gently rattle the skull, that is directly stimulating the inner ear the cochlea itself, Singh says. This is called bone conduction. We humans, however, are much more attuned to the sound waves striking our eardrums. As a result, the sound quality of bone conduction is not as good as regular air conduction.



Plus, its difficult to figure out where a sound is coming from underwater. On land, if someone starts talking on your right side, sound waves hit your right ear before your left. This slight variation in timing helps your brain find the source of a sound. But sound travels much faster in water than in air. Thats because the particles that make up liquids are closer together. In water, there is virtually no time difference between sound hitting each ear. That makes underwater noise sound very full, like its coming from everywhere.









Our sea-dwelling relatives



To hear their friends talk and sing properly, mermaids might have evolved hearing structures more like aquatic animals.



Marine mammals, such as whales, dolphins and seals, hear in a way very similar to humans, notes Colleen Reichmuth. A biologist, she studies marine mammals at the University of California, Santa Cruz. These creatures have cochleae. They also have ear bones and eardrums, though not always functional. And they have evolved some adaptations to help them hear under the sea.





The lower jaw of dolphins and some whales contains fat that directs sound to the bony middle ear. This fat has a special chemical composition that makes it really suitable for transmitting acoustic waves, says Laela Sayigh. Shes a marine biologist at Hampshire College in Amherst, Mass., and Woods Hole Oceanographic Institution in Massachusetts.



Some marine mammals, such as seals, have convertible ears. On land, the animals can open ear holes to pick up sound waves traveling through air. But when diving, their ear tissue swells with fluid, plugging the holes. The fluid-filled ears help transfer sound from the water to the cochleae.





Those features could help a mermaid hear her friends songs more clearly. But if mermaid voices were more like those of marine mammals, their vocal systems could get a major upgrade, too.



Whales, dolphins, seals and other marine mammals can sing underwater, creating complex noises with musical notes or rhythms. They produce sound by passing air along tissues to vibrate them, similar to a humans voice box. But unlike people, who must breathe out to make noise, many of these sea creatures dont need to expel air from their mouths or blowholes to produce sound.



Underwater, air is a precious commodity, says Joy Reidenberg. If whales exhaled when using their voices, they would have to keep resurfacing for more air. That would interrupt their lengthy songs, Reidenberg says. She studies animal anatomy at the Icahn School of Medicine at Mount Sinai in New York City.



Instead, whales and dolphins can move air around in their bodies and even reuse it. This air recycling system would certainly help a mermaid sustain conversation or song below the surface, Reichmuth says.



For a voice that really carries, mermaids might be built like baleen whales. These whales, which include humpbacks, have huge vibrating structures in their throats that toss out sound. Some can make noises so loud and low-pitched too low for humans to hear that the songs could potentially travel more than 1,000 kilometers (600 miles) in the ocean. (Lower-pitched sound waves lose less energy when traveling through water than higher-pitched ones.)



Humpback whales sing beautiful, lengthy songs. But they dont need to breathe out of their mouths or blowholes to do it. These whales recycle the air supply in their bodies and can stay submerged for nearly an hour. Craig Lambert/iStock/Getty Images Plus



Something sounds fishy



A mermaids mammal upper half may not be the only part that could make or hear sounds. Crustaceans and fish are known to make quite a ruckus, too. In fact, snapping shrimps, typically around four centimeters (1.5 inches) long, are some of the loudest creatures on Earth. As the name implies, these shrimp snap one of their claws to produce a colossal sound.



Many fish use a similar method to make noise. They click or rub their bodys bony structures together. Sea horses, for example, produce clicks by knocking the tops of their skulls into the horns on their heads. They do this when wooing a mate.



You can think of it like clicking your teeth together, says Audrey Looby. A marine ecologist, she studies fish at the University of Floridas Nature Coast Biological Station in Cedar Key.



Other species can use their muscles to vibrate an internal organ, like playing a drum. Some fish can even communicate by expelling air out their backside, Looby says. Essentially, fish communicating through farting. And they have special cells lining the sides of their bodies that can sense vibrations in the water, helping them to hear.



If you met a mermaid, she might have both fish-like and mammalian structures to communicate with her underwater friends. Motion-detecting cells may line her tail, and her ears may work like a seals to hear both in and out of water. She would probably recycle her bodys air supply to talk and sing without having to keep resurfacing. But her conversations may also be sprinkled with teeth chattering, clapping and even farting.

Ghostly particles from space are giving us a new view of our galaxy.



Known as neutrinos, these subatomic particles have little mass and no electric charge. Theyre sometimes called ghost particles. Thats because they easily pass without a trace through gas, dust and even stars. High-energy neutrinos zip everywhere throughout the cosmos, carrying information about distant places. But where the particles come from has typically been a mystery.



Lets learn about ghost particles



Now, researchers found the first signs of high-energy neutrinos coming from within our Milky Way. They mapped the particles to create a new image of our galaxy. Its the first made with something other than light.





The map also hints at possible sources for these high-energy neutrinos. They could be the remains of past supernovas star explosions. Or they might come from the cores of collapsed supergiant stars or other unidentified objects. More research is needed to figure out the sources for all these neutrinos.



The new map of our galaxy was unveiled June 30 in Science.



Previously, only a few high-energy neutrinos have been traced back to their potential birth. They all came from outside the Milky Way. Two appeared to come from black holes shredding their companion stars. Others came from a type of galaxy called a blazar.



Explainer: Stars and their families



Its clear now that researchers are spotting neutrinos from both inside and outside our galaxy, says Kate Scholberg. Shes a physicist at Duke University in Durham, N.C., who did not take part in the new mapping project. Theres so much more to learn, she says. It can be tremendous fun to figure out how to see the universe with neutrino eyes.



Those neutrino eyes might one day allow us to see distant objects in a way that no other telescopes can match.



Some telescopes rely on visible light. Others pick up X-rays, gamma rays or the charged particles that make up cosmic rays. All of those types of light can be deflected or absorbed as they travel through space. Neutrinos, though, can cross huge expanses without being deflected. This allows the particles to tell us about very distant objects.




Three ways to map the Milky Way



Here are views of the Milky Way in visible light (top), gamma rays (middle) and high-energy neutrinos (bottom). Dust obscures portions of the visible-light map, and a variety of sources can generate gamma rays. Neutrinos have the potential to pinpoint remnants of supernovas, cores of collapsed stellar giants and other cosmic features.


IceCube Collaboration/Science 2023IceCube Collaboration/Science 2023





New look at old data



The ability of neutrinos to pass through things so easily also makes them extremely hard to detect. Scientists found the Milky Way particles using a neutrino detector in Antarctica. Called IceCube, this detector is embedded deep in the ice. To better detect ghostly neutrinos, its enormous. Its 5,160 sensors are arranged in a cube one kilometer (3,281 feet) on each side.



Even so, the experiment sees only a tiny share of the neutrinos that zip through space. IceCube scientists observe 100,000 or so neutrinos a year. Some of these neutrinos leave tracks in the detector. The scientists can sometimes trace these tracks back to the neutrinos source. Most of the neutrino signals that IceCube picks up, though, are a type called a cascade event. These leave bursts of light in the detector, but do not reveal a neutrinos origins as well as tracks can.



Astronomers used to throw away data on cascade events, says Naoko Kurahashi Neilson. Shes a physicist at Drexel University in Philadelphia, Pa. Those data can hold useful information about where the neutrinos come from. Its just hard to pick out which of those tens of thousands of cascade events are most important.





Kurahashi Neilson and her team took up the challenge. They dug through a decade of IceCube cascade-event data. They enlisted the help of an artificial-intelligence system known as a neural network. You can train the neural nets to identify which events are worth keeping, Kurahashi Neilson explains.



She pioneered this approach in 2017. Over the years, Kurahashi Neilson has steadily improved it. She and her colleagues have now used it to identify the neutrinos used to make the new map.



Its an impressive analysis, Scholberg says. And the technique may have the potential to be developed even more. Clearly a lot more work needs to be done, she says. But its very exciting to see the basic expectation [of Milky Way neutrinos] verified.

This ancient predator had two spiny appendages sticking out of its face. This creature Anomalocaris canadensis may have been the freakiest thing to ever haunt the sea. For decades, scientists thought it used those strange limbs to snatch trilobites off the seafloor. The beast could then crush and eat these crunchy snacks. But a new study hints that A. canadensis instead used its spiny limbs to swiftly hunt soft prey. 



Researchers shared their new findings on July 12. The work appeared in Proceedings of the Royal Society B.





A. canadensis means the abnormal shrimp from Canada. It prowled the seas roughly 500 million years ago. Only about as long as a housecat, it still was one of the biggest animals of the Cambrian Period. (The Cambrian ran from about 540 million to 485 million years ago.) That makes A. canadensis one of the earliest top predators.





These sea monsters were like the orcas or great white sharks of their time, says Jakob Vinther. He did not take part in the new study. But he is a paleontologist at the University of Bristol in England. 



Some researchers thought A. canadensis hunted another iconic Cambrian critter the trilobite. Thats because people have unearthed lots of fossils of injured trilobites. This hinted that something had attacked them. A. canadensis became a prime suspect.



But Russell Bicknell wasnt so sure. After all, trilobites have hard, thick exoskeletons. And no one had shown that A. canadensis could crack that armor.



Bicknell is a paleobiologist. He works at the American Museum of Natural History in New York City. He was part of a team that set out to learn if A. canadensis really could have crushed and chowed down on trilobites.



This is a closeup of an A. canadensis fossil. It was found in the Burgess Shale of Canada. The fossil shows the creatures head and curled front appendages.Allison Daley


Pinning softies with its spikes



The researchers compared the ancient creatures bendy appendages to those of modern arthropods. These animals include todays insects, spiders and crustaceans. Bicknells team also built computer models of the limbs on A. canadensis. Using those models, the team tested the limbs toughness, range of motion and best swimming position.



The ancient spiky limbs would have been good at grabbing prey. In that way, A. canadensis may have hunted much like todays whip spiders. But the limbs of A. canadensis probably were too fragile to attack armored prey. Those would have included trilobites.





Plus, A. canadensis would have moved most efficiently when its appendages were stretched out front. (Think of how Superman holds his arms while in flight.)



Together, these results suggest that A. canadensis was best suited for chasing soft creatures swimming through the water. It would have snagged prey in its spiky clutches, Bicknell says. It was going to absolutely pincushion something soft and squishy.

Scientists may have just found the longest gravitational waves yet.



Gravitational waves are ripples in the fabric of spacetime. Kicked up by massive objects, they roll through the universe like water waves on the surface of the ocean. The newfound gravitational waves are light-years long. That means it would take years for light to travel the distance of a single ripple.



Explainer: What are gravitational waves?



Whats more, these waves wash through the universe nonstop. They constantly jostle Earth and the rest of our galaxy.





Pairs of huge supermassive black holes are thought to trigger these waves. Those black-hole behemoths sit at the centers of galaxies. Scientists think that when two galaxies collide, their black holes pair up and orbit each other. This action could churn up those gravitational waves in spacetime.



Indeed, across the universe, galaxies often mingle and merge. As they do, scientists had suspected their supermassive black holes would orbit each other. In the process, these black holes would give off gravitational waves. In fact, they should pump out waves nonstop for millions of years. Many supermassive-black-hole pairs in the many merging galaxies across the cosmos would send out their spacetime ripples at once. This, scientists thought, should create a constant mishmash of very long gravitational waves.



Explainer: What are black holes?



On June 28, researchers shared the first clear evidence of such a background of gravitational waves. Those data came from several teams around the world.



Scientists must confirm that the newly spotted waves are real and that they do come from pairs of huge black holes. But if so, its miraculous, says Meg Urry. Shes an astrophysicist at Yale University. Thats in New Haven, Conn.



Confirming the new findings would offer the first proof that the biggest black holes in the cosmos can spiral into each other and merge. Its extremely interesting, Urry says. The reason? We have essentially no handle on what the most massive black holes are doing.



Catching a new kind of wave



Since 2015, scientists have spotted lots of gravitational waves. Some have come from smashups between neutron stars. Others have come from colliding black holes. But the black holes in those collisions were small, by cosmic standards. Most were less than 100 times the mass of our sun. Their smashups created blips of gravitational waves that detectors on Earth felt for mere fractions of a second.



Those supermassive black holes thought to cause the newfound gravitational waves are entirely different beasts. Each can have the mass of millions or billions of suns.



The Earth is just randomly bumping around on this sea of gravitational waves, says Maura McLaughlin. Shes an astrophysicist at West Virginia University in Morgantown.





Compared to the gravitational waves seen before, this is a very different sort of thing, says Daniel Holz. This astrophysicist works at the University of Chicago, in Illinois. He and others have used the LIGO detector to spot gravitational-wave blips from small black-hole smashups.



To find waves from supermassive black holes required a whole new technique.





Peering at pulsars



For this new research, scientists looked to objects called pulsars. Theyre spinning remnants of exploded stars. Like celestial lighthouses, pulsars emit beams of radio waves as they spin. Their beams sweep past Earth at regular intervals. Those flashing beams of radio waves are picked up, like the precise ticks of a clock, by telescopes on Earth.



Gravitational waves can stretch and squeeze the space between a pulsar and Earth. In that way, such ripples in spacetime could cause a pulsars ticks to reach Earth early or late. Scientists have now used this effect to search for the gravitational waves from supermassive black holes as they roll through space.



A project called NANOGrav has watched dozens of pulsars for 15 years. (NANOGrav is short for North American Nanohertz Observatory for Gravitational Waves.) The NANOGrav team now thinks it finally has evidence of gravitational waves from pairs of supermassive black holes. The team just shared its findings in Astrophysical Journal Letters.



Scientists searched for gravitational waves by watching dozens of spinning stars called pulsars. Here, each pulsar is shown as a blue dot against a gray illustration of our Milky Way galaxy. The yellow star (near center) shows where Earth sits in the Milky Way.NANOGrav


Its really invigorating stuff, says Michael Keith. Hes an astrophysicist at the University of Manchester in England. Hes also a member of the European Pulsar Timing Array, or EPTA.



The EPTA team spent an even longer time staring at pulsars about 25 years. We were starting to think maybe the signal is just so weak, well never ever find it, Keith says. But like NANOGrav, EPTA has now seen evidence for gravitational waves altering pulsar signals.



EPTAs results have been accepted in the journal Astronomy and Astrophysics. The European group teamed up with researchers from the Indian Pulsar Timing Array to do the work. Teams from Australia and China have now shared evidence for gravitational waves from pairs of supermassive black holes, too.



Astronomers used a variety of radio telescopes to view pulsars in their hunt for gravitational waves. One of those telescopes was the Effelsberg radio telescope (shown) in Germany.Tacken, MPIfR


Its not over yet



Some scientists had thought that supermassive black holes in merging galaxies would never draw close enough to merge. In that case, they wouldnt give off gravitational waves like the ones scientists think they have now observed.



Its actually been a sore spot for our field for many years, Chiara Mingarelli says. Mingarelli is an astrophysicist on the NANOGrav team. Shes based at Yale University.



But if the new gravitational-wave signal is real, it seems to be stronger than expected. That suggests that supermassive black holes spiraling into each other are common. This, in turn, hints that mergers between such black holes also are common.



But none of the teams sharing new data say they have for sure detected gravitational waves from huge black-hole pairs. They just say theyve found strong evidence for this. Thats because each of their observations comes with some uncertainty. In the future, the separate teams plan to join forces. Combining their data may help confirm the detection.



Still, even if the waves are real, its possible they dont come from pairs of monster black holes. Such huge black holes appear to be the simplest explanation. Still, researchers cant rule out a more exotic one. For example, the ripples might have arisen from the fast expansion of the universe just after the Big Bang.



Learning more about supermassive black holes is key to understanding the galaxies that host them. So whatever the source of the potential new gravitational waves, their future study is bound to have ripple effects.

Pulsar (noun, PUHL-sahr)



Pulsars are dense, quickly spinning cores of dead stars that blast radio waves into space.



When a star thats a few times as big as the sun dies, it shoots most of its mass off into space in a huge explosion. That explosion is called a supernova. But the core of the star collapses in on itself and forms an ultra-dense neutron star. All that mass clumps together under the force of gravity. That causes the dead star to spin faster, just like an ice skater pulling in their arms during a turn. Neutron stars can spin faster than the tires on a race car at top speed anywhere from once every few seconds to hundreds of times per second. Thats millions of times faster than the Sun spins.





A pulsar is a special kind of neutron star that blasts out two beams of radio waves in opposite directions. As the dead star spins, those beams sweep through space like the lights on a lighthouse. If Earth is in the path of one of those beams, we see a flash of radio waves every time it sweeps past us. That makes the pulsar appear to pulse at very regular intervals.



This animation shows a pulsars radio beams (purple) sweeping through space. When one of the beams passes over Earth, the pulsar appears to flash.



Astronomer Jocelyn Bell Burnell first discovered pulsars in 1967. At first, some scientists thought the radio beams she saw might be coming from aliens. That was because the pulses were so regular. But then Bell Burnell found radio pulses coming from a different part of space, far from the first signal. It was unlikely that two groups of aliens were signaling us at the same time from so far apart, so scientists looked for a different explanation. They eventually learned the radio waves were coming from pulsars scattered throughout space.



Scientists today use pulsars to make maps of space and keep time in the cosmos. Pulsars can also be used study the fundamental laws of physics that rule the universe.



In a sentence



Scientists time the radio flashes from pulsars to look for gravitational waves.



Check out the full list of Scientists Say.

Butterflies and bees do it. Frogs and even salmon do it. What is it? Its metamorphosis.



The term describes a series of dramatic physical changes that an organism undergoes as it matures. The term comes from the Greek word for change of form.



Lets learn about amphibians



Lots of young animals look different from their parents. But metamorphosis is distinct from just growing up. Some animals emerge from metamorphosis with brand-new organs, such as wings or lungs. Others switch what types of food they eat or may wind up not eating at all! These differences may benefit animals by minimizing competition for resources between adults and babies of the same species.Insects, amphibians and certain fish are among the more well-known animals that metamorphose. But theyre not the only ones. Jellyfish, mollusks and sea stars have all been observed undergoing this real-life shapeshifting. Crabs, lobsters and other crustaceans have, too.





Body remodel



Many animals that metamorphose have babies that look entirely different from their adult forms. Think of a frog. Frogs have powerful back legs and lungs. But many frog species start life underwater as tadpoles. Unlike frogs, tadpoles rely on gills and long tails to maneuver underwater.



Jellyfish, meanwhile, start out as free-swimming young called larvae. These larvae attach to hard surfaces and transform into anemone-like polyps. These polyps spend much of their early lives using their tentacles to catch passing prey. Eventually, the tentacles begin to bud into free-floating jellies. They then detach from their home surface and hit the high seas.



Like jellyfish, sea urchins also start their lives as larvae swimming in the ocean. These larvae use long arms to snag phytoplankton to eat. During metamorphosis, a sea urchin grows adult limbs and organs from a cluster of cells inside its body called a rudiment. The urchins absorb their larval arms and mouths into their bodies. Then they drop to the seafloor as newly formed adults.



These spiky purple sea urchins started out life as free-swimming larvae before they underwent metamorphosis into their current forms.Brent Durand/Getty Images


Insect transformations



Metamorphosis is especially common in insects. But some insect transformations are more dramatic than others.



Take butterflies. A crawling, leaf-munching caterpillar can transition into a flying, nectar-sipping butterfly within a few weeks. This is an example of complete metamorphosis. During this type of metamorphosis, insects go through four life stages: egg, larva, pupa and adult. At each stage, the insect will look completely different.



Explainer: Insects, arachnids and other arthropods



The process begins with an egg laid by an adult. A small, soft-bodied larva, such as a caterpillar, hatches from this egg. Larvae do not have many of the organs found in adults. And they have one goal: eat as much as they can.A caterpillar doesn’t have wings, doesn’t have any reproductive organs, says Jens Rolff. It’s just like a big bag of tissues moving on a plant and feeding. Constantly feeding. Rolff is an evolutionary biologist who studies insects. He works at Freie Universitt in Berlin, Germany.Healthy appetites help a larva pack on fat. And that will fuel the development of its organs once the larva becomes a pupa. At the pupa stage, the larva stops eating and develops a protective covering. Caterpillars develop a hard, outer layer called a chrysalis.







When the larva pupates, the job is to generate a new animal, says Rolff. Inside the pupa, proteins called enzymes begin to break down the larvas tissues. These dissolved tissues are used to rebuild muscles and organs such as the brain and gut. Special groups of cells called imaginal discs become activated and help create wings, new mouthparts and reproductive organs. Once these changes are complete, an adult insect emerges.



That adult often moves and eats in totally different ways than it did as a pupa.



About eight in every 10 insect species undergo complete metamorphosis. Beetles, flies, bees, ants and fleas are just a few examples. Together, this group makes up about 60 percent of all animals on Earth. Complete metamorphosis has been around for a while, too. Fossils suggest that insects were doing it at least 250 million years ago, Rolff says.





Check out one of the worlds largest beetles going through metamorphosis in this video from Nat Geo WILD.



Not all insects go through this full process, though. Grasshoppers, cockroaches, cicadas and dragonflies go through a three-stage version known as incomplete metamorphosis.



Here, insects emerge from eggs as nymphs, which look much like miniature adults. They are just missing developed wings and sex organs. Nymph forms of these species gradually get larger by shedding their hard outer shell, or exoskeleton, through a process called molting. Wings and reproductive organs continue to develop with each molt. All insects grow by molting. But insects that undergo complete metamorphosis only do so while plumping themselves up as larvae. Nymphs will go through multiple molts until they reach adulthood.

Massive Otodus megalodon sharks the oceans largest meat-eaters ever ran hot. It now appears that their rise (and fall) may have been tied to their warm-bloodedness.



Chemical measurements on fossil O. megalodon teeth suggest the sharks had higher body temperatures than surrounding waters. Analyses of carbon and oxygen in the teeth revealed that the giant sharks body temperature was about 7 degrees Celsius (13 degrees Fahrenheit) warmer than seawater temperatures at the time.





Lets learn about sharks



That warm-bloodedness may have been a double-edged sword. The trait may have helped megalodons become swift, fearsome apex predators. Those are hunters at the top of the food chain. O. megalodon grew up to 20 meters (66 feet) long. That makes it one of Earths biggest carnivores ever. But the sharks voracious appetite also may have spelled the species doom.



A creatures metabolism is the set of chemical reactions needed to sustain life. Gigantic bodies require a lot of food to power their metabolisms, notes Robert Eagle. A marine biogeochemist, he studies the chemistry of ocean ecosystems. Massive sharks may have been particularly vulnerable to extinction when food became scarce, he says. Eagle was part of a team that studied fossils of O. megalodon and its living and extinct kin to learn about the animals metabolisms.



Game over for megalodons



Mammals can boost their metabolisms and maintain their body heat, even in colder environments. This trait is called endothermy or warm-bloodedness. Some families of fish, both living and extinct, can do something similar. They can keep some body parts warmer than the surrounding water. This is known as regional warm-bloodedness. Many modern sharks belonging to the group that includes great white sharks have this ability.



Jacking up the temperatures of some body parts is one way some sharks evolved to be giant, says Jack Cooper. A paleobiologist, he studies ancient life at Swansea University in Wales. He did not take part in the new study. Filter feeding offers another path to getting large, Cooper points out. Gentler giants, such as whale sharks, use this strategy when they gulp lots of water and eat the tiny creatures within.



Scientists have long thought megalodon was regionally warm-blooded, Eagle says. Estimates of this beasts body shape, swimming speeds and energy needs point to some warm-bloodedness. The shark also was known to hunt in both colder and warmer waters. That suggests it had some control over its body temperature.





The question, Eagle says, isnt really whether O. megalodon was warm-blooded. Its how warm-blooded. His team wondered how the megasharks internal temps compared to one of its major competitors: the great white shark.



O. megalodon evolved around 23 million years ago. It went extinct sometime between 3.5 million and 2.6 million years ago. Great white sharks emerged late in megalodons reign, roughly 3.5 million years ago. They competed for food with their massive cousins.





Some scientists suspect this competition helped drive O. megalodon to extinction, especially when food became scarcer. The climate changed during the Pliocene Epoch, which spanned 5.3 million to 2.6 million years ago. That led to a sharp drop in the numbers of marine mammals. They were a primary food source for both sharks.



But the great whites stuck around when O. megalodon died out, Eagle says. Being the much smaller of the two, they likely needed less food to maintain their metabolism.



Ancient temperature check



To study the ancient sharks body temperatures, the team turned to the only fossils left by these sharks: their teeth.



Fossilized teeth can say a lot about the bodies they came from. A tooths enamel contains isotopes, heavier and lighter forms of a chemical element. Eagles team examined chemically bonded forms of heavier-than-usual carbon and oxygen. The technique acted as a kind of ancient thermometer. The abundance of bonds between these isotopes is only affected by body temperature, Eagle says.



Explainer: What are chemical bonds?



The team used this technique on teeth from great whites and megalodons. They also used it on other animals who lived at the same time. Mollusks are entirely cold-blooded; they cant control their body temperature. Analyzing ancient mollusks revealed the oceans water temperature.



Great whites and megalodons were at least somewhat warm-blooded, the team found. A megalodons body was warmer than the water around it. It also was warmer than the bodies of great white sharks. Neither shark, however, was as warm-blooded as marine mammals, such as whales.



The researchers shared their findings June 26 in Proceedings of the National Academy of Sciences.



It’s fantastic that we have more evidence for regional warm-bloodedness in megalodon, Cooper says. O. megalodons higher body temperature would have allowed it to swim further and faster, he says. That increased its chances of finding prey. But when the sharks prey dwindled some 3 million years ago, he says, megalodon may well have starved into extinction.



Eagles team is now exploring the chicken-or-egg question of which came first for megalodons: warm-bloodedness or apex-predator status. You need to be big to be a mega-predator. But its not clear whether carnivores need to be warm-blooded to become apex predators. Were hoping to fit it all together into an evolutionary story as to what drives what.

In 2022, an underwater volcano in the South Pacific island nation of Tonga made history. It spewed a plume of ash and water high enough to touch space. It also launched a tsunami as tall as the Statue of Liberty. Now, scientists find that it triggered lightning at the highest altitudes ever seen.



The eruption plume sparked lightning flashes that began 20 to 30 kilometers (about 12 to 19 miles) above sea level. Thats all the way up in the stratosphere even higher than most airplanes fly.





Researchers shared these findings on June 28. The work appeared in Geophysical Research Letters.



Lets learn about lightning



Lightning is most often born inside storm clouds. But lightning can also form inside a volcanos eruption plume. That plume is made of tiny bits of ash, gas and dust. When these tiny bits bump into each other, they make static electricity. Once enough static electricity builds up, lightning zips through the plume.



Alexa Van Eaton led a team that looked at how high the Tonga eruptions lightning was. Shes a volcano scientist at the U.S. Geological Surveys Cascades Volcano Observatory. Thats in Vancouver, Wash.



To estimate the lightnings height, Van Eatons team looked at a few different types of data. One was radio waves created by the lightning. They also examined satellite images of the eruption plume and infrared light from the flashes.



These data revealed the lightning started more than 20 kilometers (12 miles) above sea level. Lightning doesnt typically start that high. Air pressure at that height is usually too low to form lightning leaders. These are the channels of hot plasma that make up the lightning in thunderstorms.



Explainer: The volcano basics



The rising eruption plume may have increased the air pressure over the volcano, says Van Eaton. That might have been enough to create lightning leaders at strangely high altitudes.



In those eruption data, were seeing stuff that weve never seen before, says Jeff Lapierre. Hes a coauthor on the study. Hes also the principal lightning scientist at the Advanced Environmental Monitoring. Its a company based in Germantown, Md.



This eruption has completely changed the way we think of how natural events can change the atmosphere, Lapierre says. Its also changed the environment where we thought lightning could exist.

Predator and Prey, (nouns, PREH-duh-tor and PRAY)



The words predator and prey describe the roles in a relationship between two species. In this relationship, one species eats the other. The predator is the species that does the eating. The prey is the one that gets eaten. Predator/prey relationships are important links in food webs. These links move energy and nutrients through an ecosystem.



A bear fishing salmon from a river is one example of a predator/prey relationship. The bear is the predator. The salmon is the prey. But salmon must eat too. They snack on plankton, insects and other small critters. So in those cases, the salmon plays the role of predator.





Animals arent the only predators and prey. A rabbit chomping on grass is a predator, while the grass is its prey. But plants can also play the role of the predator. For example, a Venus flytrap (Dionaea muscipula) snares flies in its leafy jaws and digests them.



Predators and prey drive each others evolution. Over time, predators adapt to better catch prey. For example, the cheetahs powerful body can out-race its impala prey. But prey have evolved ways to avoid being eaten. The nimble impala can make a hard swerve that leaves behind the cheetah. Many plants have toxins, spines or other defenses that make eating them unpleasant. And millions of years ago, the need to escape marine predators likely helped drive some species from water to land.



In a sentence



Thanks to its predator/prey relationship with ants, the Australian ant-slayer spider (Euryopis umbilicata) evolved a cool somersault technique for capturing prey.



Check out the full list of Scientists Say.

Spacing out spaceflights may be better for astronauts brains.



Fluid-filled chambers in the human brain expand while in space. Its one way they adapt to lower gravity. But after a space mission, these structures dont shrink back right away. It might take three years to return to normal. Researchers reported this June 8 in Scientific Reports.



This suggests astronauts might need at least that long between flights before their brain is ready to be in space again.





With little gravity in space, fluids build up in an astronauts head. Sometimes their faces even look puffy when space travelers first arrive at the International Space Station, says Rachael Seidler. She studies how the human body adapts to space. She works at the University of Florida in Gainesville.



Extra fluid also collects in four chambers in the brain, called ventricles. Astronauts often return to Earth with enlarged ventricles. These chambers are filled with liquid that cushions the brain and clears out cellular wastes. In space, the ventricles expand as they take in more fluid, Seidler says.



She and her colleagues wanted to see how time spent in space affected the brain.





They examined MRI scans of the brains of 30 astronauts. Ones taken before each astronauts missions were compared to those taken after time in space. The longer the mission, the more that three of the four ventricles seemed to expand. (The fourth ventricle is very small, Seidler notes. So any changes in it may have been too tiny to see.)



Two-week spaceflights didnt have much effect. Both six- and 12-month missions, though, resulted in larger ventricles. The amount was similar after these longer trips, suggesting the swelling slows after six months in space.



Eighteen of the astronauts had flown in space before. The time since their last mission seemed to affect how much their brains changed during the new mission that the researchers were studying. In those whose last trip to space was three or more years earlier, three of their ventricles got bigger on average, by roughly 10 to 25 percent. Other astronauts had been to space less than three years prior. Their ventricles didnt swell much if at all. That suggests their brains may not have had enough time between missions to fully recover, the scientists say. 



Surviving Mars missions will take planning and lots of innovation



Im glad that the [study] authors took the first step and are looking at this question, says Donna Roberts. Shes a brain-imaging specialist at Medical University of South Carolina in Charleston. There are so many variables that could play into the brain changes that were seeing, Roberts says. Its hard to sort them out.



Spaceflights effects on the brain are even more pressing now, she notes. NASA aims to send people to Mars, which could be a two-year round trip. Everybody talks about the rocket technology to get to Mars, Roberts says. But the humans thats the real challenge.

For photosynthesis, one photon is all it takes.



Plants, algae and some bacteria perform photosynthesis. This chain of chemical reactions lets them transform sunlight into energy that they can use to grow. At the smallest scales, light is made up of particles called photons. Scientists long suspected that a single photon could spark photosynthesis. Until now, no one knew for sure.



The new experiment used a light source that produces just two photons at a time. One photon flew off to a detector. This particle signaled when the two photons had been released. The second photon went into a solution that contained light-absorbing structures from a bacterium. This species (Rhodobacter sphaeroides) can photosynthesize. It has light-harvesting structures called LH2. Each LH2 contains two rings of molecules.





Explainer: How photosynthesis works



In normal photosynthesis, LH2 absorbs a photon and then passes its energy to a series of other groups of molecules. Eventually the energy is turned into a form of chemical energy. That energy fuels the microbe.



But in the new experiment, there was nothing to hand that energy off to. So when LH2 absorbed the second photon shot out by the light source, it gave off a third photon. This photon had a different wavelength (light hue) than the one LH2 had absorbed. The new wavelength was a sign that energy had passed from the first ring of LH2 to the second. And thats step one of photosynthesis.



The researchers detected the photon given off by LH2. Then they compared the timing of its detection to when they detected the first photon spit out by their light source. This comparison confirmed the second photon had kicked off photosynthesis.



Researchers shared their findings June 14 in Nature.





Plants and bacteria do photosynthesis differently. In plants, multiple photons must be absorbed independently to complete photosynthesis. But the first steps in the process are similar enough that a single photon would set off photosynthesis in plants too, says Graham Fleming. This chemical physicist works at the University of California, Berkeley. He took part in the new research.



The role of single photons isnt surprising, says Richard Cogdell. Hes a biochemist who did not take part in the tests. He works in Scotland at the University of Glasgow. The important thing here, he says, is the technique that Flemings team used.



Many similar experiments have relied on light from lasers. But lasers shine much denser beams of photons than sunlight. In real life, photons rain down on the molecules that do photosynthesis in plants and bacteria at a much lower rate. Just a few tens of light particles with the right wavelengths hit these small areas each second.



Using only a single photon in the lab more closely mimics that real-world process. You can really work out whats happening in the early reactions in photosynthesis, says Cogdell. Its as if you could shrink yourself down and watch these photons moving around.

Northern elephant seals are the true masters of the power nap.



These marine mammals swim at sea for months between brief breaks on shore. During those sea voyages, the seals snooze less than 20 minutes at a time. On average, they get a total of just two hours of shut-eye per day.



This extreme sleep schedule rivals African elephants for the least sleep seen among mammals.



Researchers shared the discovery in the April 21 Science.



Its important to map these extremes of [sleep behavior] across the animal kingdom, says Jessica Kendall-Bar. She studies marine mammals at the University of California, San Diego. Learning how much or how little sleep different animals get could help reveal why animals, including people, sleep at all.





Knowing how seals catch their zzzs also could guide efforts to protect places where they sleep.





Tracking seal sleep



Northern elephant seals (Mirounga angustirostris) spend most of the year in the Pacific Ocean. At sea, those animals hunt around the clock for fish, squid and other food.



The elephant seals, in turn, are hunted by sharks and killer whales. The seals are most vulnerable to such predators at the sea surface. So they come up for air only a couple minutes at a time between 10- to 30-minute dives.



People had known that these seals dive almost all the time when theyre out in the ocean. But it wasnt known if and how they sleep, notes Niels Rattenborg. He wasnt involved in the new study, but he has studied animal sleep. He works in Seewiesen, Germany, at the Max Planck Institute for Biological Intelligence.



Explainer: How to read brain activity



Kendall-Bars team wanted to find out if northern elephant seals really do sleep while diving. To do this, the researchers outfitted two northern elephant seals with special caps. Those caps recorded the animals brain waves, revealing when they were asleep. Motion sensors were also strapped onto the seals.



By looking at both brain-wave readings and motion data, the researchers could see how seals moved while asleep.



Kendall-Bars team took their two seals from Ao Nuevo State Park. Thats on the coast of California, north of Santa Cruz. The researchers then released the seals at another beach, one about 60 kilometers (37 miles) south of Ao Nuevo. To swim home, the seals had to cross the deep Monterey Canyon. The waters here are similar to those in the deep Pacific, where the seals swim during their months-long trips at sea.





Matching the seals brain-wave readings to their diving motions on this journey showed how northern elephant seals get their sleep on long voyages.



Deep-sea snoozes



The data revealed that when a northern elephant seal wants to sleep at sea, it first dives 60 to 100 meters (200 to 360 feet) below the surface. Then, it relaxes into a glide. As the seal nods off, it keeps holding itself upright for several minutes.



But then, the seal slips into a stage of rest known as REM sleep. During this sleep stage, the animals body becomes paralyzed. A slumbering seal now flips upside-down and drifts in a gentle spiral toward the seafloor.



A northern elephant seal can descend hundreds of meters (yards) deep during one of these naps. Thats far below the waters where sharks and killer whales normally prowl. When a seal wakes after a five- to 10-minute nap, it swims back to the surface. The whole routine takes about 20 minutes.



Explainer: Tagging through history



Now that Kendall-Bars team knew how seals moved during sleep, they could pick out naps in motion data from other seals who hadnt been outfitted with the special caps.



The researchers looked for naptime dive motions in tracking data on 334 other northern elephant seals. Those seals had been outfitted with tracking tags from 2004 to 2019. The seals movements revealed that while at sea these creatures conk out, on average, only around two hours per day.



But northern elephant seals arent short on sleep all the time. They snooze nearly 11 hours per day when they come on land to mate and molt. On the beach, they can catch up on sleep without worrying about getting eaten.



What the seals are doing [at the beach] might be something like what we do when we sleep in on the weekend, Rattenborg says.



Northern elephant seal naps are no joke. While on land, these animals can conk out for a solid 11 hours per day. But at sea, the seals catch only brief bits of sleep.Photo by Jessica Kendall-Bar, NMFS 23188



Extreme animal sleep



Northern elephant seals arent the only animals that sleep very little, at times, and then a whole lot. Rattenborgs group has found a similar sleep pattern in great frigate birds. They fly over the ocean. They can sleep while theyre flying, Rattenborg says. So on those trips, they sleep less than an hour a day for up to a week at a time, he says. Once back on land, they sleep over 12 hours a day.



Curiously, the sleep habits of northern elephant seals seem quite different from those of other marine mammals. When studied in the lab, many marine mammals sleep with just half their brain at a time. That half-awake state allows dolphins, fur seals and sea lions to constantly watch for predators. They literally sleep with one eye open.



Its pretty cool that elephant seals get by without one-sided sleep, Kendall-Bar says. Theyre shutting off both halves of their brain completely and leaving themselves vulnerable. Diving far below predators is what allows the seals to rest easy.



It seems the key to their enjoying such deep sleep is sleeping deep in the sea.

Tectonic plate (noun, Tek-TAHN-ick PLAYT)



Earths outermost layer, or lithosphere, is broken up into a giant jigsaw puzzle of tectonic plates. These huge slabs of rock hold both Earths continents and its seafloor. Theyre around 100 kilometers (miles) thick on average and include both Earths crust and upper mantle. Earth is covered in about a dozen main tectonic plates. And its the only planet known to have tectonic plates.



Explainer: Understanding plate tectonics



Earths tectonic plates continually slide around atop the hot, swirling rock beneath them. They move only a few centimeters per year. But over millions of years, those tiny movements add up. When tectonic plates bump into each other, they push up mountains. When plates slide beneath each other, they can form volcanoes. Plates can also slide past each other. Each of these movements can trigger earthquakes.



Even more dramatically, the shuffling of tectonic plates can give Earths surface a complete makeover. More than 200 million years ago, Earth had only one huge landmass: Pangaea. Over time, the shifting of tectonic plates broke that landmass apart and gave rise to the continents we see today.



In a sentence



A single catastrophic collision may have given Earth both its moon and its tectonic plates.



Check out the full list of Scientists Say.

Put a miniature poodle next to a wolf. The little poodle has a short, wiry coat. It has tiny, delicate paws. It has a puffy tail that sticks straight out or curls up. It is probably happy to play fetch, get snuggles or be dressed up in cute outfits, and to look to people for all its needs. The large wolf, in contrast, looks like a wild animal. It has a scruffy coat and fur that blends into its background. This doglike creature hunts with its pack and doesnt need or want anything to do with people.



These two animals arent so far apart biologically. They can even mate and produce puppies. But the biggest difference is that the ancestors of one of these animals the poodle became domesticated and developed a close relationship with humans.





Domestication is a process, says Sarah Crowley. She studies the relationship between humans and animals at the University of Exeter in England. And its a process that many familiar animals have undergone. These include dogs, of course, as well as cats, sheep, cattle, pigs and goats.





The process of domestication takes place over many animal and human generations. The animal may end up with changes in its genes, appearance and behavior. Its a relationship and process that affects us, too, Crowley notes. As people live closer and closer to those animals, human behaviors can adapt and change.



This is different from simply taming an animal, notes Greger Larson. Hes an evolutionary biologist at Oxford University in England. Monkeys taken captive as babies or tigers doing tricks on TV are tamed. But theyre not domesticated. A tamed animal is an animal that was an organism that was living in a wild context away from people, he says. When it was young, someone captured it and got it used to people. It is therefore less likely to eat you. It might still [eat you], but now it kind of knows you.



Domestication, on the other hand, is a long-term population shift, Larson explains. Consider two groups of sheep. One lives wild, while another hangs around people. Over time, the sheep living near people start to relax. The animals might rely on the people for food. The people also change their behavior with the sheep. The humans might pen the sheep, shear them or breed them instead of letting the sheep romance each other. Hundreds or thousands of years later, the wild sheep and now-domesticated sheep are completely different in both appearance and behavior.



A wild mouflon (left) doesnt look much like a fluffy white domesticated sheep (right). The two animals also behave very differently. But sheep were probably domesticated from mouflon more than 10,000 years ago in Mesopotamia, an area near present-day Iraq and Iran.Dave/iStock/Getty Images Plus; George Pachantouris/Getty Images


The question of domestication syndrome



Scientists have attempted to identify traits that all domesticated animals have. These would be traits that make domesticated animals different from wild ones. All together, these traits are often called domestication syndrome.



Decreased fearfulness and aggression are behaviors that are generally assumed to follow domestication, says Christina Hansen Wheat. We expect domesticated animals to be more social and playful. Hansen Wheat is a behavioral ecologist. She studies how animals interact with each other in an environment. She works at Stockholm University in Sweden.



With domestication syndrome, tame behaviors go along with physical changes, explains Hansen Wheat. Domesticated animals might have curly tails and floppy ears. They would be more likely to have white spots. They might also be able to breed when they are younger than their wild cousins. Some can breed all year round instead of having a breeding season. They might have smaller brains and bigger bodies.





At first glance, this seems to make sense. Domesticated dogs, pigs, sheep, horses and cows can all have floppy ears and often have white spots.



However, theres a problem. Scientists have made many guesses about why domestication syndrome might occur. But none have been shown to be true. This could be because when scientists look closer, domestication syndrome itself falls apart, says Larson. No domesticated animal has every single trait in the syndrome, he notes. Instead, domestication syndrome might be people trying to see common traits in the animals they are close to.



People live with their cats, live with their dogs, horses, cows and sheep and pigs. And so, everybody feels like they know what it is, he says. We are primed to see differences when those things matter to us.



Domestication syndrome, Larson says, is also based on the idea that humans intended to domesticate an animal in the first place. When we think about all the animals now that are very close to us, none of them were animals that any one person deliberately went out and said, I’m going to make this a domestic animal, he notes. No one grabbed the first sheep and put it in a barn until it behaved.



Instead, animal domestication is a growing relationship. Humans and another species get closer and closer. Eventually, they couldnt imagine a life apart. Its a relationship that affects us just as much as it affects the animals, Crowley says. And the relationship is always changing. Some animals might get closer to us, while others get released to run wild again, such as pigeons.



In the end, Larson says, the math to make a domestic animal is simple: an organism, plus people, plus time.

There are diapers in this house but not where you might think. Used diapers partly make up its floors, columns and walls.



A team of researchers tested used diapers as one ingredient in building material. To build a new house, the team mixed recycled disposable diapers into concrete and mortar. Mortar is used to hold bricks together.



The team designed a single-story home that covers about 36 square meters (388 square feet). Recycled diapers could replace nearly 2 cubic meters (71 cubic feet) of its building materials. These findings appeared May 18 in Scientific Reports.





Repurposing diapers to make building materials would shrink the amount of trash that goes to a landfill. It could also make homes more affordable, the team says. Thats a big need in developing countries such as the Southeast Asian nation of Indonesia. There, demand for low-cost housing outstrips whats available.



The number of people in Indonesias cities has climbed by about 4 percent per year in the last 30 years. And more people are moving to the countrys urban centers. By 2025, more than two-thirds of Indonesians are expected to live in urban areas, says Siswanti Zuraida. An environmental engineer, she works at the University of Kitakyushu in Japan. Zuraida is from Indonesia. All the waste people make is becoming a problem, she says. And Indonesias population boom is straining the demand for housing.



Building materials especially those that make for strong structures are often expensive. Theyre often the biggest barrier to making homes affordable. So researchers have previously investigated unusual materials that could save costs. These materials included many that would otherwise pile up as waste, such as the husks of rice grains or fly ash. Thats the fine particles left over from burning coal.



Maybe giving old diapers a new use could help tackle both problems. Used disposable diapers mostly pile up in landfills or get burned. But disposable diapers contain wood pulp, cotton and plastic. All of those are potentially useful building materials.





A diaper change



Mortar and concrete are typically made from sand, gravel and other materials. Zuraida and colleagues tried replacing some of those materials with used diapers. Then they tested their mixtures to see if structures built with them would be strong enough.



The diapers have to be cleaned up before being reused. The team washed, dried, sterilized and shredded diapers. Then they made six different samples of concrete and mortar. Each used differing amounts of diapers, cement, sand, gravel and water. Crushing the samples in a machine revealed how much weight each could bear. Adding more diaper material reduced the strength of the mixture, they found.



The team designed and built a small home based on the maximum amount of diaper waste they found they could use. Their one-story house had two bedrooms and one bathroom. Recycled diapers could replace up to 27 percent of the typical materials used in load-bearing structures. Those are the structures that help hold up a building, such as columns and beams.







Taller buildings cant use as much diaper material, the team found. A three-story home could use up to 10 percent disposable diapers in load-bearing structures. But other parts of homes dont have to support a lot of weight. Those include garden paving blocks and walls that divide rooms. There, shredded diapers could replace up to 40 percent of the sand.



But there are big hurdles to adopting diapers or other unusual building materials, Zuraida says.





Diapers plant-based fibers can be used for building. But their plastic parts would have to be separated out. That takes a complicated process that, for now, is available only in developed nations. And Indonesias laws restrict what materials can be used for construction. Right now, its just concrete, bricks, wood and ceramics. (Making such materials emits a lot of greenhouse gases.)



The idea of building with waste is worthwhile, says Christof Schrfl. A chemist, he works at Technische Universitt Dresden in Germany. Schrfl wasnt part of the new work. But reusing diapers might not be that environmentally friendly, he says, especially on a large scale. Its tricky to separate dirty diapers from waste and sanitize them. So it would take a lot of energy to recycle diapers.

Objective: To measure the effect of temperature on the rate of a chemical reaction



Areas of science: Chemistry, science with your smartphone



Difficulty: Easy intermediate



Time required: 25 days



Prerequisites: None



Material availability: Readily available



Cost: Very low (under $20)



Safety: Adult supervision may be needed when working with hot water solutions



Credits: Andrew Olson, PhD, Science Buddies; edited by Svenja Lohner, PhD, Science Buddies






You may have seen a television commercial for Alka-Seltzer tablets or heard one of their advertising slogans: Plop, plop, fizz, fizz, oh what a relief it is! When you drop the tablets in water, they make a lot of bubbles, like an extra-fizzy soda, as shown in the main image up top (Figure 1). And like a soda, the bubbles are carbon dioxide gas (CO2). However, with Alka-Seltzer, the CO2 is produced by a chemical reaction that occurs when the tablets dissolve in water.





Alka-Seltzer is a medical drug that works as a pain reliever and an antacid (antacids help neutralize stomach acidity, such as heartburn). The pain reliever used is aspirin and the antacid used is baking soda (sodium bicarbonate, NaHCO3). To take the tablets, they should be fully dissolved in a glass of water. When sodium bicarbonate dissolves in water, it dissociates (splits apart) into sodium (Na+) and bicarbonate (HCO3) ions. (An ion is a molecule that has a charge, either positive or negative.) The bicarbonate reacts with hydrogen ions (H+) from citric acid (another ingredient in the tablets) to form carbon dioxide gas and water. In other words, carbon dioxide gas is a product of this reaction. The reaction is described by Equation 1 below:



Equation 1.3HCO3 + 3H+ 3H2O + 3CO2



So how is temperature related to this bicarbonate reaction? In order for the reaction shown above to occur, the bicarbonate ions have to come into contact with the hydrogen ions. Molecules in a solution are in constant motion and are constantly colliding with one another. The hydrogen and bicarbonate ions must collide at the right angle and with enough energy for the reaction to occur. The temperature of a solution is a measure of the average motion (kinetic energy) of the molecules in the solution. The higher the temperature, the faster the molecules are moving. What effect do you think temperature will have on the speed, or rate, of the bicarbonate reaction?



In this chemistry science project, you will find out for yourself by plopping Alka-Seltzer tablets into water at different temperatures and measuring how long it takes for the chemical reaction to go to completion. In addition, you can record the sound of the Alka-Seltzer fizzle using a smartphone equipped with a sensor app. Do you think it will fizz more loudly in hot or cold water?



Terms and Concepts




Chemical reaction



Alka-Seltzer



Baking soda, or sodium bicarbonate



Molecule



Products



Temperature



Bicarbonate reaction



Reaction rate




Questions




What is the bicarbonate reaction? What are its products?



Keeping in mind that an increase in temperature reflects an increase in the average molecular motion, how do you think increasing temperature will affect the reaction rate?



What temperature change do you think would be required to increase, or decrease, the reaction time by a factor of two?



What other factors besides temperature can affect how well a chemical reaction takes place?




Materials and Equipment




Alka-Seltzer tablets (at least 12; if you plan to do additional variations to the project, you will want to get a larger box)



Thermometer with a range of at least 0C to 60C (32F to 140F)

A suitable thermometer is available from Amazon.com



A standard kitchen candy thermometer will also work fine





Clear drinking glasses or jars; about 8 ounces, or 240 milliliters (two of the same size)



Graduated cylinder, 100 mL. A 100 mL graduated cylinder is available from Amazon.com. Alternatively, measuring cups may be used.



Masking tape



Hot and cold tap water



Ice



With option 2 in procedure: Stopwatch or a clock or watch with a second hand



Optional: A helper



Lab notebook



Pencil



With option 1 in procedure: Smartphone with a sensor app such as phyphox, available for free on Google Play for Android devices (version 4.0 or newer) or from the App Store for iOS devices (iOS 9.0 or newer).



With option 1 in procedure: Small sealable (waterproof) plastic bag that fits your phone inside of it




ConditionTemperature(C)Reaction Time(s)Optional: Maximum Sound Intensity(dB)Trial #1Trial #2Trial #3AverageTrial #1Trial #2Trial #3AverageHot Tap Water         Cold Tap Water         Ice Water         Table 1. In your lab notebook, make a data table like this one. You will record your results in it.



Experimental Procedure



Note: In this science project, you will investigate how water temperature affects the dissolving time of an Alka-Seltzer tablet. You will use a smartphone equipped with a sensor app to record the fizzing sound of the Alka-Seltzer reaction in water and measure the time it takes for one Alka-Seltzer tablet to react completely in water. The app creates a graph that will not only give you information about the reaction time but will also allow you to assess how loud each reaction was based on the measured sound intensities. If you do not have a phone, you can observe the reaction and use a stopwatch to time how long it takes for each tablet to dissolve.



Figure 2. Mark your glass on the outside with masking tape to indicate a water level up to about 1 inch below the rim.M. Temming



Do your background research and make sure that you are familiar with the terms and concepts in the Background.



In your lab notebook, make a data table like Table 1. You will record your results in this data table.



Prepare a drinking glass so that it is marked at the 200 mL point. You will use the same glass for multiple trials, so it is convenient to mark the desired water level. Note: If your glass fits more than 8 ounces, make a mark about 1 inch below the rim.

Add 200 mL (a little less than 1 cup) of water to the drinking glass, or fill it up to about 1 inch below the rim.



Use a piece of masking tape on the outside of the glass to mark the water level, placing the tape with its top edge even with the water level in the glass, as shown in Figure 2.



Note: You do not want to fill the glass completely full because the bicarbonate reaction produces bubbles that could splash out.





You will fill the drinking glass with the same volume of water at three different temperatures: hot tap water, cold tap water and ice water.

For the hot and cold tap water, run the water until the temperature stabilizes. Fill the glass with water to the level of the masking tape. Be careful when handling the hot water.



For ice water, fill the glass about half full with ice cubes, then add cold tap water to a bit above the level of the masking tape. Stir for a minute or two so that the temperature equilibrates. Once temperature has equilibrated, remove the ice cubes from the water’s surface using a spoon or other utensil immediately before adding the Alka-Seltzer tablet. (Pour out any extra water so that the water is up to the level of the masking tape.)





Prepare the drinking glass with one of the three temperatures as described in step 4. Then measure the reaction time for that temperature either by following option 1 (sensor app), described in step 6, or option 2 (stopwatch), described in step 7.

If you use the phyphox app to measure the amplitude of sounds, you will need to calibrate the sensor first to get correct decibel readings on your device. The sensor has to be recalibrated between individual recordings. Instructions on how to do the phyphox sound sensor calibration are provided in the video above.



Option 1: Using the Sensor AppSensor apps such as phyphox let you record data using sensors that are built into many smartphones, including a microphone that you can use to measure sound. In this project, you can use the app to record the fizzing sound that the Alka-Seltzer tablet makes while it dissolves in water and then use the data to determine the reaction time and maximum sound intensity for each reaction.



Open the sensor app on your phone and select the sound sensor (audio amplitude in phyphox). Remember, that when you are using the phyphox app you will have to calibrate the audio amplitude sensor (sound sensor) before you do any measurements. Do this calibration before you start your investigation, so you get correct sound intensity readings. To calibrate your sound sensor in phyphox, follow the instructions in the sound sensor calibration video. You will have to re-calibrate the audio amplitude sensor (re-set the decibel offset) every time you start a new recording! Once you have calibrated the sensor, make sure you know where the microphone is located on your phone and do a quick test to see if your sound measurement is working. For example, you could record yourself clapping or singing to check if the sensor behaves as expected.



Once you have confirmed that the sensor works and you are familiar with the app, you can start with the experiment. You should do this experiment in a quiet environment. The background reading of your sound meter when there is no noise in the room should be in the range between 2040 decibels (dB).



Measure the temperature of the water (in Celsius [C]) in the first glass that you prepared, and record it in the data table in your lab notebook. Remove the thermometer from the glass before continuing with the next step.



Put your phone in the waterproof plastic bag and make sure it is sealed well. You don’t want it to get wet!



Place the second, same-sized glass, next to the glass filled with water. Lay your phone on top of the second glass so that the microphone (or sound sensor) is located right at the center above the glass filled with water, as shown in Figure 3.Figure 3. Place your phone on top of the glass filled with water so that the microphone (or sound sensor) is located right at the center above the solution.M. Temming





Take one whole Alka-Seltzer tablet out of its package and hold it above the glass filled with water. In the phyphox app, start a new recording for your first experiment by pressing the play button.



Once the recording starts, drop the tablet into the water. Note: You have to be very quiet during the experiment. Any sound that you make will be recorded and could affect your data. Try to be as quiet as possible while you are recording your data!



You will immediately see and hear bubbles of CO2 streaming out from the tablet.



The tablet will gradually disintegrate. Observe the graph recorded by the app, and how the sound sensor is responding to the fizzling while all of the solid white material from the tablet disappears.



When the solid material has completely disappeared, and you see on the graph that the sound intensity has reached background levels again or does not change anymore, wait 20 more seconds until all the bubbles have stopped forming, and stop recording your data. Make sure to save your data and label it appropriately such as “hot water,” “cold water” or “ice water.” Figure 4. This example data from the phyphox app demonstrates how to measure the reaction time of the Alka-Seltzer tablet dissolving. The x-axes of the graphs are time in seconds [s] and the y-axes shows sound intensity in decibels [dB].Made with phyphox by M. Temming





Your data should look something like the graph in Figure 4. Your graph should show an increased sound intensity for as long as the Alka-Seltzer reaction took place. The sound level of the reaction might be louder in the beginning and decrease as the tablet gets smaller. In the graph, every bubble that pops in the solution is represented by a spike.



Measure the time between the beginning of your reaction (when you dropped the tablet and the sound intensity started to increase) and the end of the reaction (when the sound intensity reached background levels again or does not change significantly anymore). In phyphox, you can use the pick data function to select the respective data points and view their time and decibel values. For example, the reaction in Figure 4 started a little after 3 seconds and ended at about 66 seconds.



Calculate the time difference between these two points. The result is the reaction time for your first trial. Record the reaction time (in seconds [s]) in the data table in your lab notebook.



Tip: Be careful when opening the packets and handling the Alka-Seltzer tablets. The tablets are thin and brittle, so they break easily. If some of the tablets are whole, and some are broken into many pieces, the separate trials will not be a fair test. You should only use whole tablets.





Option 2: Using the stopwatch

After filling the glass to the level of the masking tape, measure the temperature of the water (in Celsius [C]), and record it in the data table in your lab notebook.



Remove the thermometer from the glass before continuing with the next step.



Have your helper get ready with the stop watch, while you get ready with an Alka-Seltzer tablet. Have your helper count onetwothree. On three, the helper starts the stop watch and you drop the tablet into the water.



You will immediately see bubbles of CO2 streaming out from the tablet.



The tablet will gradually disintegrate. Watch for all of the solid white material from the tablet to disappear.



When the solid material has completely disappeared, and the bubbles have stopped forming, say “Stop!” to have your helper stop the stopwatch.



Record the reaction time (in seconds [s]) in the data table in your lab notebook.



Tip: Be careful when opening the packets and handling the Alka-Seltzer tablets. The tablets are thin and brittle, so they break easily. If some of the tablets are whole, and some are broken into many pieces, the separate trials will not be a fair test. You should only use whole tablets.





Repeat step 6 or 7 two more times with the same temperature of water. If you use the sensor app, make sure your sound sensor is still calibrated and recalibrate it again (re-set the decibel offset) if necessary before each recording.

Repeating an experiment helps ensure that your results are accurate and reproducible.





Repeat steps 5 and 6 or 5 and 7 for each of the other temperatures.

When you are done, you should have done a total of three trials for each of the three temperatures.





Calculate the average reaction time for each of the three water temperatures. Record your results in the data table in your lab notebook.



Make a graph of the average reaction time, in seconds (on the Y-axis), vs. water temperature, in degrees Celsius (on the X-axis).



How does reaction time change with temperature? Can you explain why this is?

Hint: If you are having trouble explaining your results, try re-reading the Introduction in the Background.





If you chose to use a sensor app to record your data, look at the graphs for each water temperature again. Write down the maximum sound intensity that you observed during the Alka-Seltzer reaction (not including the initial or end peaks) for each trial. You can get the number in the phyphox app by using the pick data tool to select the timepoint at which the sound intensity is highest. In the example shown in Figure 4, this would be around 35 seconds with a sound intensity of about 50 decibels. Calculate the average for each of the three water temperatures and record your results in the data table in your lab notebook.



Make a graph of the average maximum sound intensity, in decibels (on the Y-axis), vs. water temperature, in degree Celsius (on the X-axis).



Which reaction was the loudest? Did you expect these results?






Variations




More advanced students should also calculate the standard deviation of the reaction times for each temperature.

Use the standard deviation to add error bars to your graph.



For example, say that the average reaction time for one temperature was 45 seconds, and the standard deviation was 5.2 seconds (these are made-up numbers). You would graph the symbol for the data point at 45 seconds, and then draw short vertical bars above and below the symbol. Each vertical bar would have a length equivalent to 5.2 seconds.



Error bars give your audience a measure of the variance in your data.





Adult supervision required. Is reaction rate predictable over a larger temperature range? Water remains liquid above 0 C and below 100 C. Repeat the experiment at one or more additional high temperatures to find out. Use Pyrex glass for containing water heated on the stove or in the microwave, and use appropriate care (e.g., wear hot mitts and safety goggles) when handling hot water. A standard candy thermometer should be able to measure the temperatures in this higher range.



You could turn the bicarbonate reaction into a home-made lava lamp. To do this, you will want to use a tall jar or empty clear plastic 1-liter or 2-liter bottle, fill it with 2 to 5 centimeters (cm) of water, add 5 drops of food coloring, and then fill it at least three-quarters full with vegetable oil. You could repeat the science project using your homemade lava lamp at a cold and a hot temperature. To do this, you will need to figure out a way to make the prepared bottle hot or cold. (For example, to make it hot you could let it sit in a large bowl of hot water, and to make it cold you could store it in a refrigerator or freezer.) You will also want to use one-quarter of an Alka-Seltzer tablet at a time (instead of a whole tablet). How does the bicarbonate reaction look and function in the home-made lava lamp?




This activity is brought to you in partnership with Science Buddies. Find the original activity on the Science Buddies website.

On Jupiter, lightning jerks and jolts a lot like it does on Earth. 



New views of storms on Jupiter hint that its lightning bolts build by lurching forward. Whats more, those staggering steps happen at a similar pace to lightning bolts on our own planet. 



Arcs of lightning on both worlds seem to move like a winded hiker going up a mountain, says Ivana Kolmaov. A hiker might pause after each step to catch their breath. Likewise, lightning on Earth and Jupiter both seem to build by one step, another step, then another, Kolmaov says. Shes an atmospheric physicist at the Czech Academy of Sciences in Prague. Her team shared the new findings May 23 inNature Communications.  





The discovery about Jupiters lightning doesnt just offer new insights into this gas giant. It could also help aid in the search for alien life. After all, experiments hint that lightning on Earth could have forged some of the chemical ingredients for life. If lightning works a similar way on other worlds, it might produce lifes building blocks on distant planets, too. 



Lightning, step by step 



Here on Earth, winds within thunderclouds whip up lightning. The winds cause many ice crystals and water droplets to rub together. As a result, those tiny bits of ice and water become electrically charged. Bits with opposite charges move to opposite sides of the clouds, building up charge on either end.  



Lets learn about lightning



When that charge buildup gets big enough, electrons are released the lightning takes its first step. From there, the surging electrons repeatedly rip electrons off molecules in new segments of air and rush into those segments. So the bolt of lightning leaps forward at tens of thousands of meters per second, on average. 



Scientists thought Jupiters lightningmight also form by ice crystals and water droplets colliding. But no one knew whether the alien bolts grew step by step, as they do on Earth, or if they took some other form. 



Views from Juno 



Kolmaovs group looked at data from NASAs Juno spacecraft. Specifically, they looked at pulses of radio waves given off by Jupiters lightning. The data included hundreds of thousands of radio wave pulses from lightning over five years. 



Radio waves from each lightning bolt seemed to happen about once per millisecond. On Earth, lightning bolts that stretch from one part of a cloud to another pulse at about the same rate.This hints that Jupiters lightning builds in steps that are hundreds to thousands of meters long, too. 







Step-by-step lightning is not the only possible explanation for what Juno saw, says Richard Sonnenfeld. Hes an atmospheric physicist who wasnt involved in the study. He works at the New Mexico Institute of Mining and Technology in Socorro.   



The radio pulses could have come from electrons running back and forth along bolts of lightning, Sonnenfeld says. On Earth, such currents cause some bolts to appear to flicker. Still, he says, stop-and-go lightning formation is a perfectly reasonable explanation for the data. 

Its common to hear the term chaos used to describe seemingly random, unpredictable events. The energetic behavior of kids on a bus ride home from a field trip might be one example. But to scientists, chaos means something else. It refers to a system that is not totally random but still cannot be easily predicted. Theres a whole area of science devoted to this. Its known as chaos theory.



In a non-chaotic system, its easy to measure the details of the starting environment. A ball rolling down a hill is one example. Here, the balls mass and the hills height and angle of decline are the starting conditions. If you know these starting conditions, you can predict how fast and far the ball will roll.





A chaotic system is similarly sensitive to its initial conditions. But even tiny changes to those conditions can lead to huge changes later. So, its hard to look at a chaotic system at any given time and know exactly what its initial conditions were.



For example, have you ever wondered why predictions of the weather one to three days from now can be horribly wrong? Blame chaos. In fact, weather is the poster child of chaotic systems.





The origin of chaos theory



Mathematician Edward Lorenz developed modern chaos theory in the 1960s. At the time, he was a meteorologist at the Massachusetts Institute of Technology in Cambridge. His work involved using computers to predict weather patterns. That research turned up something strange. A computer could predict very different weather patterns from almost the same set of starting data.



But those starting data werent exactly the same. Small variations in the initial conditions led to wildly different outcomes.



To explain his findings, Lorenz likened the subtle differences in starting conditions to the impacts of the flapping wings of some distant butterfly. Indeed, by 1972 he called this the butterfly effect. The idea was that the flap of an insects wings in South America might set up conditions that led to a tornado in Texas. He suggested that even subtle air movements such as those caused by butterfly wings could create a domino effect. Over time and distance, those effects might add up and intensify winds.



Does a butterfly really affect the weather? Probably not. Bo-Wen Shen is a mathematician at San Diego State University in California. This idea is an oversimplification, he argues. In fact, the concept has been generalized mistakenly, Shen says. Its led to a belief that even small human actions could lead to huge unintended impacts. But the general idea that tiny changes to chaotic systems can have huge effects still holds up.





Maren Hunsberger, a scientist and actress, explains how chaos is not some random behavior, but instead describes things that are hard to predict well. This video shows why.



Studying chaos





Chaos is difficult to predict, but not impossible. From the outside, chaotic systems appear to have traits that are semi-random and unpredictable. But even though such systems are more sensitive to their initial conditions, they do still follow all the same laws of physics as simple systems. So the motions or events of even chaotic systems progress with almost clock-like precision. As such, they can be predictable and largely knowable if you can measure enough of those initial conditions.



One way scientists predict chaotic systems is by studying whats known as their strange attractors. A strange attractor is any underlying force that controls the overall behavior of a chaotic system.



Shaped like swirling ribbons, these attractors work somewhat like wind picking up leaves. Like leaves, chaotic systems are drawn to their attractors. Similarly, a rubber ducky in the ocean will be drawn to its attractor the ocean surface. This is true no matter how waves, winds and birds may jostle the toy. Knowing the shape and position of an attractor can help scientists predict the path of something (such as storm clouds) in a chaotic system.



Chaos theory can help scientists better understand many different processes besides weather and climate. For instance, it can help explain irregular heartbeats and the motions of star clusters.

Coral (noun, CORE-uhl)



Corals are tiny marine animals that live in clustered groups on the ocean floor. Each group contains hundreds or even thousands of individuals. An individual coral animal is called a polyp. Polyp describes a kind of body shape a long, thin body shape that often flares at one end like a vase. The corals base attaches to a solid surface, such as a rock. At the top, stinging tentacles sprout around the mouth and capture plankton drifting past.





Many coral species build porous structures called coral reefs. The kinds of coral that build reefs are often called “hard coral, stony coral or reef-building coral. The polyps of reef-building corals secrete chemicals that harden around their soft bodies. When polyps die, this hard structure remains behind and new polyps may attach to it. This cycle repeats over time, forming elaborate structures with different shapes. For example, the staghorn coral (Acropora cervicornis) gets its name from its antler-like prongs. Brain coral (Diploria labyrinthformis) looks you guessed it like a brain.



Most reef-building corals contain zooxanthellae photosynthetic microbes that live inside coral polyps. Just like plants, zooxanthellae use sunlight to make sugar, which the coral eats. In return, the zooxanthellae get protection inside the reef. But not all corals make coral reefs. Soft corals refer to non-reef builders. These are often mistaken for plants since they can sprout wildflower-like clusters of bendy, whiplike animals with feather-like tentacles.



Coral reefs are important marine ecosystems. They make up less than one percent of the entire oceans floor. But they are home to nearly one-quarter of all marine species. For example, over 4,000 fish species make their home among the coral reefs. Hundreds of other species, from shrimp to sea stars to sea grass, also live in coral reef ecosystems.   



But corals are vulnerable to changes brought about by human activity. For example, excess fertilizer washes from crop fields into our oceans, fertilizing marine algae. That causes algae growth, which clouds the water and starves the sun-loving zooxanthellae and their coral buddies. Since many other life forms depend on corals for food, shelter and other needs, the coral death can upend life in these ecosystems and beyond.



In a sentence



Scientists saved some sick coral by treating them with amoxicillin a common antibiotic.



Check out the full list of Scientists Say.

It sounds unbelievable, but scientists from Harvard University believe our entire universe may have been created in a lab by an advanced civilization with an immense knowledge of physics and how to control it.

On March 27, 2022, Troy Kotsur becamethe first Deaf male actor to win an Oscar.The 53-year-old, who won Best Supporting Actorfor his portrayal ofFrank Rossi in "CODA," isonly the second Deaf actor to attain the prestigious award. In 1987,Marlee Matlin took home the Best Actress awardfor her role as Sarah in the movie "Children of a Lesser God."

The SouthernTropical Andes, which comprisesareasof Ecuador, Peru, and Bolivia, is one of the world's most biodiverse regions especially when it comes to amphibians. The areais home to about980amphibianspecies, including over half of the 150-knownglass frog species. Now, two new membersof the tiny frogs have joined thisever-growing list.

For pranksters, there is no better holidaythan April Fools' Day. Celebrated annually on April 1, it is the only day of the year when fun, harmless hoaxesgo unpunished. Themischievous holiday has murky origins. Somebelieve itstarted in 1582when France transitioned from the Julian calendar which began the year around April 1 to the currently usedGregorian calendar. Thoseunaware, or unwilling, to accept thedate change werepranked.Others thinkthe holiday startedas a cheerful way to mark the start of spring.

Dr. Madeleine Jana Korbel Albright, the firstfemale US Secretary of State, passed away on March 23, 2022. A statementreleased by her family revealed that the 84-year-oldhad been suffering from cancer.Thehighest-ranking woman in the history of the Americangovernment at the time of her appointment,Dr.Albrightplayed a crucial role in shaping USforeign policy in the 1990s.

The residents ofNew Orleans can't seem to catcha break from natural disasters. Just over a year after being battered by Hurricane Ida,the beautiful city has been hit by a powerful tornado. The twister, which boasted wind speeds of 160 mph,made landfallshortly before 8:00pm local time on March 22, 2022.

A massive plume ofdust and sandfrom the Sahara Desert engulfed parts of Europe in mid-March. Storm Celia blew into Spainon March 14, 2022, turningthe skiesinto aneerie rusty orangeand covering the ground and vehicleswith finesand particles. The thick dust layerlingered for several days,causingofficials to issue extremely poor air quality ratings in the capital city of Madrid and acrosslarge parts of Spain'ssoutheast coast.

When you see a panda at the zoo, it stands out against the green bamboo that it eats all day. But that setting is misleading. In the wild, the pandas black-and-white patches help it to blend in with its background. That keeps the animal camouflaged against predators like tigers, leopards and dholes, a type of wild dog, a new study finds.



We have been fooled into thinking that [pandas] are much easier to see than they are in the wild. If we want to understand animal coloration, we need to look at species where they live, says Tim Caro. Hes a zoologist at the University of Bristol in England. He is a co-author on the new study, which was published October 28 in Scientific Reports.



The giant panda (Ailuropoda melanoleuca), a rare species of bear, lives in remote mountain forests in southwest China. Earlier research had shown that pandas white patches help them blend into snowy areas. And their dark legs and shoulders match well with shady bits of forest. Or at least they do to human eyes.







We tend to usually overestimate how well animals can see because our own color perception is so good, says Ossi Nokelainen. He is an ecologist at the University of Jyvskyl in Finland.



For their new study, Nokelainen, Caro and their colleagues obtained 15 images of pandas in the wild. They then corrected the photos to match how domestic dogs and cats would see the images. Dogs and cats arent dholes and tigers, but their vision should be similar. And the images showed that the pandas should be well-camouflaged from their predators, at least from a distance.



This makes sense, says Nokelainen, since pandas have to stay in one place, fairly still, for a long time to eat enough bamboo. They can just evade the predators in a way that they cant be detected easily by the predators.







































JoAnna Wendel




What did you think of this comic? Let us know by taking this short survey. Thanks!

A seriesof deadly tornadoesswept across a large swath of the Midwestern and SoutheasternUS overnight onDecember 10, 2021.TheNational Weather Service (NSW)estimates that the severe storms spawned about50 twisters across eight states Arkansas, Indiana,Kentucky, Missouri, Mississippi, Tennessee, Ohio, and Illinois.

Savanna (noun, Suh-van-uh)



If you’ve ever seen The Lion King, you’ve seen a savanna. A savanna is a rolling grassland scattered with trees and shrubs. This type of ecosystem covers about 20 percent of the world’s land. That includes nearly half of Africa. The African savanna is home to lions, hyenas, zebras and other Lion King creatures. The Australian savanna hosts animals like kangaroos and wallabies. Savannas are also found in South America and Asia. And in North America, the oak savanna is one of the worlds most endangered ecosystems.



Most people may be familiar with the African savanna. But did you know North America has savannas, too? These grasslands are scattered with oak trees.Steepcone/Wikimedia Commons (CC BY-SA 3.0)



Most savannas don’t have the four seasons you might be familiar with. These areas alternate between dry winters and wet summers. During the winter, a savanna may not get rain for months at a time. That prevents many trees from growing there. Dry conditions also allow savannas to catch fire easily. Those fires prevent young trees from growing up and turning these habitats into forests. But heavy summer rains help thick grasses grow. That prevents the savanna from being a desert.



In a sentence



African savanna elephants are the largest land mammals in the world.



Check out the full list of Scientists Say.

Egyptian archaeologistshave discoveredthousandsofancientstructures and even entire cities.However, finding thesix sun templesconstructed by the Fifth Dynastypharaohshas proved elusive. Only two hadbeen found until recently,andthe last one was unearthed 50 years ago.

Low power. Your device will power down unless plugged into a power outlet.



How many of us have gotten such a warning from one of our digital devices? Looks like its time to plug it in and recharge the batteries with electricity.



But what is electricity?



Electricity is the term we use to describe the energy of charged particles. Electricity might be stored, like in a battery. When you connect a battery to a light bulb, electricity flows. This happens because electrical charges (electrons) are free to carry energy from the battery through the bulb. Sometimes electricity is described as the flow of electrons between neighboring atoms.





Several terms help us describe electricity and its potential to do work.



Current refers to the flow of electric charges. That is, how much charge is moving per second. When people talk about electricity, theyre usually referring to electric current.



Currents are measured in units known as amperes, or amps, for short. A single ampere of current is about 6 quintillion electrons per second. (Thats the number 6 followed by 18 zeroes.) For many devices, its common to see currents that are only thousandths of an amp, or milliamps.





Voltage offers a gauge of how much electrical energy is available to power devices. Voltage could be stored in a battery or capacitor. You may have seen a 1.5-volt label on AA and AAA batteries. In the United States, every regular electrical outlet supplies 120 volts. Large appliances like refrigerators and some air conditioners are powered by a special outlet. That outlet supplies 220 volts.



Current and voltage are related. To understand how, imagine water flowing downhill in a river. Voltage is like the height of the hill. Current is like the moving water. A tall hill could cause more water to flow. In the same way, a bigger voltage can yield a bigger electrical current.



But the height of a hill isnt the only thing that affects how the water flows. A wide riverbank would allow lots of water to flow. But if the river is narrow, the path is restricted. Not as much water can get through. And if the river gets clogged with fallen trees, the water might even stop flowing. Just like many factors affect the waters ability to flow, there are several ways that the flow of electric current can be helped or resisted.



Resistance describes how easily current can flow. A bigger voltage can lead to a bigger current, but more resistance lowers that current. Resistance varies from material to material. It also depends on the condition of a material. For instance, dry skin has a high resistance. Electricity does not easily pass across it. Getting skin wet, however, drops the resistance to almost zero.



Its important to realize that any amount of resistance may be overwhelmed by too much current trying to pass through it. As an example, electricity will not flow through wood if you simply hold the electrode of a small battery against the trunk of a tree. But a powerful bolt of lightning packs enough energy to split the tree in half.



In this simple circuit, you can see how the circuit is a loop. When the orange copper switch is open (as shown), the loop is not complete and electricity will not flow. When it is closed, electricity can flow from the battery through the circuit to turn on the light bulb.haryigit/iStock/Getty Images Plus



Circuits describe the paths that electrical currents take. Think of a circuit as a loop. In order for electricity to flow, this loop must remain closed. That means it has no gaps. When you connect a light bulb to a battery, the electricity flows from one end of the battery, through a wire, to the light bulb. Then it flows back to the battery through another wire. The circuit will continue to light the bulb as long as the loop is closed. Cut the wire and theres no longer a circuit because the path is broken.



Conductors and insulators are types of materials that respond differently to electricity. Conductors have very low resistance, so they can easily transmit a current. Most metals are very good conductors. So is saltwater. (This is why its dangerous to go swimming during a lightning storm! The chemicals in a swimming pool and the salts on our bodies make the water an especially good conductor of electricity.)



Insulators, in contrast, strongly resist the flow of electricity through them. Most plastics are insulators. Thats why electrical cords are jacketed in a layer of plastic. Electricity will flow through the copper (metal) wire inside a power cord, but the plastic coating outside makes the cord safe for us to handle.



Electricity flows through the copper wires bundled inside a power cord. The plastic coating jackets the wires so that we can safely touch the cord.Jose A. Bernat Bacete/Moment/Getty Images Plus



Semiconductors are materials that are in between conductors and insulators. In semiconductors, the flow of electricity can be precisely controlled. That makes these materials useful for directing electrical current, like tiny traffic guards, inside electronics. Computer chips depend on the ability of semiconductors to interact in complex circuits. The most common semiconductor material is the element silicon. (Not to be confused with the silicone found in flexible ice cube trays and baking tools!)



Transformers, as their name suggests, are devices that transform electrical voltage. They can be found in the box-shaped plugs at the end of device chargers. Most of these transformers convert a wall outlets 120 volts into a much, much lower level. Why? Household outlets are primed to run high-power appliances such as lamps, toasters, vacuum cleaners or space heaters. But that voltage is far more than smartphones and computers can handle. So the transformer in a charge cord steps down the electricity to a safe level that can run your device without frying it. Each device has its own specific needs for how much voltage it can handle. Thats why its important to use the right charging cable for each electronic device.



Electricity can safely power our homes and our devices when used properly. Keep in mind, however, that even common household electricity can cause severe injury or death. Always tell an adult about any broken plugs or cracked electrical wires. Dont overload circuits by plugging in too many devices at once. Never use electricity near water. And make sure that a devices power is turned off when changing its batteries. Finally, follow all of the safety warnings that come with electrical devices. Its better to be safe than to risk injury or fire.

Bacteria can have superpowers. Some flourish in almost any environment. Others can transform toxic materials into harmless sludge. A bacterium called Shewanella oneidensis can do both. But this microbe also has a much rarer superpower: It absorbs and produces electricity. In fact, new research suggests, these bacteria may be able to use energy collected from wind or solar sources to make fuels to run vehicles and more.



I think of these organisms as eating electricity, says Annette Rowe. Shes a microbiologist at the University of Cincinnati in Ohio. Her team has just identified which genes the microbe uses to gobble electricity.



Explainer: Understanding electricity



Electrons are negatively charged particles. A moving stream of them creates an electric current. Scientists already knew that Shewanella can move electrons back and forth across its cell wall. But they didnt know exactly how the microbes controlled their current, Rowe says.





The pathway for getting the electrons in and out of the cell is like a wire, says Rowe. It allows current to flow from the inside to the outside. Reverse the flow, she says, and you can drive electrons into the cell. The cell could then use those electrons to do some other job, such as generate current. Or it could store the energy to use later. Those electrons could later be used to make fuel, for example.



Rowe knew that Shewanellas cellular wire had to be controlled by genes. But which ones?



Buz Barstow was able to help. He is a biological engineer at Cornell University. Its in Ithaca, N.Y. Earlier, he had made a list of nearly 4,000 of this bacteriums genes. That list also included mutations, or changes, in those genes. Rowe tested these mutants to find the genes that made up Shewanella’s cellular “wire.”



Explainer: What are genes?



Within a cell, a gene can deleted. For the new study, Rowe and her colleagues tested groups of bacteria with groups of deleted genes. Their goal: to see which deleted genes allowed the bacteria to pull in electrons. These were likely genes involved in making the cell’s “wire.”



That was no easy task. It was really tricky to look for electron flow and track the electrons, she says. But in time they devised a clever test. They grew the different mutated bacteria on glass covered by a thin metal film. Then they attached a wire to the bacteria. When they sent an electric current through the wire, they could measure how much the bacteria absorbed or added. If electrons didnt flow, the scientists knew the deleted genes must have been the ones needed for electron flow. 



In time, they narrowed in on five such genes that Shewanella apparently uses to absorb electrons. Each gene tells the cell how to make a protein. Some of those proteins likely grab electrons and bring them into the cell. Others may send signals within the cell that guide the process. Still others can likely expel electrons from the cell.





Bacterial biofuels



Scientists see many ways to use electric microbes. One would be to make biofuels. These differ from fossil fuels, such as coal and natural gas. (Fossil fuels are rich in carbon from decayed remains of ancient living things.) Ethanol, which can be made from corn or sugarcane, is a biofuel that can be added to standard gasoline. Cars that run on diesel can be adapted to run on another biofuel. Called biodiesel, it is fuel made from vegetable oil or animal fats.



Biofuels get their carbon from sources like plants or animal wastes. One day, they may even get their carbon with the help of bacteria, says Rowe.



This technician holds a biofuel sample, an alternative to fossil fuels. One day bacteria may be able to supply the power or the carbon needed to unleash a new wave of such renewable fuels.Sue Barrt/Image Source/Getty Images Plus



Shewanella is among bacteria thatcan pluck carbon atoms out of carbon dioxide. They can use it to create other, larger molecules that could be burned as a biofuel. And powered by the electrons it gobbles, Shewanella could keep making these molecules, Rowe says.



Knowing which genes drive the electron-eating could help scientists develop new biofuels, says Rowe. Even better would be if the electrons that feed the bacteria come from wind or solar power. Such sources could power the biofuel-making process without adding warming carbon dioxide to the air.



Elad Noor is an environmental scientist. He works at the Weizmann Institute of Science. Its in Rehovot, Israel. There, hes helping to develop new ways to fix carbon that is, to pull carbon from carbon dioxide to build other chemical compounds. Using bacteria to create biofuels is attractive because the bacteria can regenerate and should be able to repurpose the carbon. Soring energy in bacteria also would be green, he adds. After all, the microbes dont need dangerous metals, as a normal battery would.



However, working with living organisms is complicated, he warns. Biological systems are hard to predict, he says. There are ways to store energy that are much more efficient.



The genes that Rowes team found in Shewanella show up in other bacteria. The group plans to search for others that can store or release electrons. Rowe also wants to try to improve Shewanellas abilities, because these are the organisms we know the most about.

E. Toby Kiers rarely wore shoes as a kid. She loved the feeling of soil between her toes. I always felt like something was under there, something secret and hidden, she says.



Now, as an adult, shes revealing that hidden world. Its a tangled network of fungus and plant roots. They all trade resources and even messages. People walk over this network all the time without even realizing its there. Yet understanding its mysteries could help us better cope with Earths changing climate.



Its pretty much the last frontier in understanding how our planet works, says Kiers. She studies fungal networks as an evolutionary biologist at Free University Amsterdam. Its in the Netherlands.



These are the mushrooms of the honey fungus. Its underground mycelia can grow to massive sizes. One individual that lives in Michigan is around 2,500 years old and has mycelia as heavy as three blue whales!Dan Molter (shroomydan) at Mushroom Observer/Wikimedia Commons (CC BY-SA 3.0)



When you think of fungus, mushrooms may come to mind. But the mushrooms that pop up above ground are temporary. The main body of a typical forest fungus remains underground. It is a vast, branching network of very thin, thread-like structures called mycelia (My-SEE-lee-uh). In just one teaspoon of soil there may be enough of these threads to span 10 kilometers (6.2 miles), writes Merlin Sheldrake in his 2020 book, Entangled Life.



All fungi need carbon to grow. Fungi that form networks may feed on the carbon in decaying wood or dead plant matter. Or they may form relationships with living plants. Some fungal networks grow around root tips, like tiny socks. These are known as EM, short for ectomycorrhizae (EK-toh-my-koh-RYE-zee). Others grow into the cells of plant roots. Known as AM, they have an even longer name: arbuscular mycorrhizae (Ar-BUS-kew-lur MY-koh-RYE-zee).





Plants get carbon from photosynthesis. But to grow, they also need nitrogen and phosphorus. Mycelia can range farther than roots to find these nutrients. So fungi and plants regularly trade with each other to get what they need. Almost all the plants in the world share resources through a network of mycelia. Mostly, plants give carbon and receive nitrogen and phosphorus. But mycelia also distribute carbon among plants and carry messages between them. Its almost like the internet or a highway system.



Suzanne Simard is a forest ecologist in Canada at the University of British Columbia in Vancouver. She was the first to show that trees could exchange carbon through fungal networks in a natural setting. A 1997 news report about that work called this the wood wide web. (Its a play on the world wide web, an early name for the internet.) This isnt a perfect metaphor, however, because a fungal system is alive and has its own agenda. But her work opened peoples eyes to the fact that a forest is a highly interconnected ecosystem.



How do networks of mycelia grow and explore? How do they connect with plants? And can their carbon-trading skills help us cope with climate change? Researchers are just starting to find answers.



This stunningly beautiful animation reveals how fungal networks grow underground. E. Toby Kiers team created the video using data captured as a real network grew in the lab.C. Biost/L. Galvez/S. Spacal



Memory without a brain



A fungus is not a plant. It also is not an animal. It belongs to its own taxonomic kingdom. Though mushrooms remain in one place like plants, mycelia can sense and explore their world. Sheldrake writes, Mycelium is a living, growing investigation. Imagine if you could divide your body in two, each side walking through a different door at the same time, then eventually rejoin with yourself. Mycelia do this. They grow in many directions in search of food. Unsuccessful ventures die off while successful ones thicken and branch further. Mycelia have no brain. Yet they fight with other fungi and with critters that graze on them. They even seem to have a basic form of memory, according to new research by Yu Fukasawa and Lynne Boddy.



At Cardiff University in the United Kingdom, Boddy studies fungi that break down things like wood and dead plants. In the 1980s, she showed how a fungal network searches for food and then re-forms itself after it finds something yummy. Last year, Fukasawa and Boddy tested the memory of a typical fungus that likes to feast on wood. They placed blocks of wood containing this fungus onto trays of soil. Then they let the fungus explore until it found a nearby block of fungus-free wood.



Next, the researchers lifted out the original block and carefully shaved off every bit of mycelia growing from it. They placed it into a new tray, with no new block of wood to discover. As the mycelia in the block began to grow again, they sent out extra threads from the side that had faced food in the past. We did this on lots of different trays and with lots of different sizes of wooden blocks, says Boddy. Almost always, you get much more growth on the side where the new food resource had been.



The fungus had somehow remembered which part of itself had faced toward food in the past. So it sent out more growth in that direction. Boddy thinks that the more researchers look, the more examples of fungal memory they will find.



This is not a mushroom. Monotropa uniflora, often called a ghost pipe, is a plant that cannot make its own food from photosynthesis. It mooches off underground mycelia for all the carbon it needs. The mycelia get that carbon from other plants in the forest.egschiller/iStock/Getty Images Plus



Hoarding and trading



A fungus that networks with living plants doesnt feast on them to get the carbon it needs. It trades. Kierss team in Amsterdam has studied how this works in AM networks. Theyre the ones that grow inside plant root cells. These mycelia regularly move nutrients through the soil. And they seem to do so with the shrewdness of a bartering salesperson.



It isnt easy to watch trading inside those microscopic threads below the ground. So the researchers developed a way to put a chemical tag on phosphorus. They added tiny dots that glow when ultraviolet light strikes them. They can make these dots glow in different colors. This lets them watch how phosphorus moves through a network.



In one 2019 study, Kierss team grew mycelia and carrot roots in small dishes. Some regions in each dish were rich in the nutrient phosphorus. Other areas had little of this fertilizer. The fungus moved phosphorus from the rich area to the poor area. Kiers thinks this happens because plants growing in a nutrient-poor area cant get phosphorus on their own through their roots. So compared to plants growing in a nutrient-rich area, those at a nutrient-poor site will trade more carbon to the mycelia for phosphorus.



In 2020, Kiers showed that mycelia will also hoard nutrients when they are plentiful. This makes those nutrients temporarily unavailable to plant roots. Then, plants have to pay [the mycelia] more carbon to get at it, says Kiers.





It seems like aliens, says E. Toby Kiers. In fact, this video shows nutrients moving through an underground network of thread-like fungus. Similar networks link plants and support ecosystems all around the world.



Invisible messages



Mycelia dont just trade with plants. They also carry their messages. Plants may seem like they sit there doing nothing. In fact, they constantly chat among themselves using chemicals. Anything that makes plants smell nice or have a flavor, thats stuff plants are making, says Kathryn Morris. And theyre most likely making it to kill other things, such as insects or disease-causing microbes, she says. Or they could make it as a signal. Morris is a biologist at Xavier University in Cincinnati, Ohio.



Plants can broadcast scent messages through the air. But they also send some through the soil. Consider when aphids attack a broad bean plant. The besieged plant blasts out chemicals that attract wasps to eat the aphids. A 2013 study showed that a broad bean plant that isnt under attack but that taps into the same fungal network as one that is will also send out these warnings. This happens even when researchers separate the plants with plastic barriers so they cant detect signals floating through the air. This suggests the plants must be sending messages underground.



It may seem like the plant in trouble is helping its neighbor. But maybe not. The plant that hasnt been attacked yet may be eavesdropping to detect when it needs to take action and protect itself. Or perhaps the fungal network carries these messages because this helps the survival of all the plants on which it depends for carbon.



Morriss research with AM networks has shown that plants chemical signals reach much farther through the soil if mycelia are there than when they arent. What she wants to know now is how this happens. How do the mycelia broadcast messages? We really dont know, says Morris. Her team is working on a method that will detect where chemicals are and how they move through fungal networks.





Yummy carbon



For a fungus, the whole point of networking with plants is to get the carbon it needs to grow. Plants get their carbon from the atmosphere. They take up carbon-dioxide gas during photosynthesis. Then they turn it into carbon-based sugars that they use to grow. Along the way, those plants will trade some of their sugars with fungi.



The globe is warming, in part, because of all the greenhouse gases that human activities spew into the air as we power our cars, electricity-generating plants, electronics and other machines. Carbon dioxide is the most common greenhouse gas. As you may already know, planting trees and boosting the health of forests can help suck extra carbon dioxide out of the air.



EM fungi form fuzzy socks around plant roots. You can sometimes see them if you look closely at roots (see upper image). Andy Taylor



But not all forests do equal work when it comes to combating climate change. The types of trees and the types of fungi that these trees communicate with can make a big difference in how much carbon a forest absorbs.



The AM fungal networks that Kiers and Morris study are by far the most common type in the world. They are ancient, says Kabir Peay. He is a biologist at Stanford University in California. These networks evolved some 500 million years ago. The mycelia in them tend to network with only one or a few trees or other plants at a time.



EM networks the type that form tiny socks around plant roots are newer. Some EM fungi can decompose dead wood or plants or network with living plants. EM networks tend to be larger and more interconnected than the AM types. Trees also find them more expensive, says Peay. By that he means they charge trees higher prices for nutrients. To make those payments, trees that trade with EM mycelia tend to absorb more carbon from the air, says Peay.



New lab research looked at how much carbon European beech trees take in when connected to an EM network. Bruna Imai is a PhD student in microbiology at the University of Vienna in Austria. After venturing into a nearby forest to collect tree seedlings, she set up pairs of baby trees in her lab. She let an EM network grow to connect some pairs. She kept other pairs from linking up.



To measure the amount of carbon the trees absorbed during the experiment, she exposed them to a special form of carbon that isnt common in nature. She found that plants that were connected to a fungal network took in nearly twice as much carbon dioxide as did plants not connected to any network. This would suggest those fungal networks can play a role in slowing climate change.



A world map of fungi



Fungal networks could be an important ally in the fight against climate change. Thats the goal, says Kiers. But first, researchers need to learn more about the complex sharing of resources and messages underfoot. Trillions of tiny worms, amoebas and microbes live in soil. Hundreds of thousands of fungal species live there, too. All of these species interact with plants and move carbon around. And they do this in ways we dont fully understand right now, says Peay at Stanford.



Explainer: What is a computer model?



Researchers also need to map fungal networks. In 2019, Peay and his team decided to start on this. Another group had already done a global tree survey. It had counted 3 trillion trees. Those data came from hundreds of researchers who went out into forests to identify individual trees and estimate their total across the planet.



Peays team wrote a computer program that looked at the mix of tree species tallied and the climate in each forest. Then it determined what type of fungal network would most likely thrive there. The result was the first world map showing where EM and AM fungal networks likely dominate. AM networks tend to prefer warm, tropical areas. EM networks prefer colder forests.



A pine forest (left) hosts mainly EM fungal networks while a tropical forest (right) hosts mostly AM networks. EM fungal networks can store higher amounts of carbon. But both types of forest store more carbon than soil in a city, farm or pasture.Kabir Peay



As Earths climate warms, forests filled with AM fungi could take over areas that are currently filled with EM fungi. Then those forests would trap even less carbon dioxide than they do now. Peay says that many EM forests are already on the edge of this sort of transformation. Plus, most land used for farming and grazing ends up with poor soil that lacks healthy fungal networks. It end up releasing carbon rather than trapping it.



Peays study didnt directly confirm the presence of particular types of fungal networks under the soil across the globe. In 2021, Kiers launched a new organization called SPUN (The Society for the Protection of Underground Networks) to take that next step. She calls it an underground climate movement.



Its goal is to protect fungal networks and use them to help heal ecosystems. It also runs a youth group called SPUN Youth (@spun.youth on Instagram and TikTok). Eventually, teens will be able to get involved. Theyll be asked to help identify fungal networks in the natural areas near their homes.



When the protection of nature only focuses on plants and animals above the ground, says Kiers, were missing half of the picture. There are ecosystems not being saved because we cant see them, she says.



She hopes that as people learn more about the living world beneath our feet, they will care more about protecting the fungal species that help trees, plants and even people thrive.

WestJet Airlines' annual "Christmas Miracle"videos,which capture employees providingmuch-needed holiday cheer to those in need, are legendary. Past "miracles" includeflyingin gifts and snow to the DominicanRepublicand hostingaholiday party for a town devastated by a forest fire. In 2020, WestJetemployees delivered 12,000care packageswith essentials and giftstofamilies hurtby the COVID-19 pandemic.This year, the company wants to reunite familiesfor the holidays.

Mention foraging bees, and most people will picture insects flitting from flower to flower in search of nectar. But in the jungles of Central and South America, so-called vulture bees have developed a taste for flesh. Scientists have puzzled over why the stingless buzzers seem to prefer rotting carcasses to nectar. Now one group of researchers thinks it has cracked the riddle. The key came from looking into the bees guts.



Bees are vegetarian, notes Jessica Maccaro, so these ones are a very large exception. In fact, shed go so far as to say these are kind of the weirdos of the bee world. Maccaro is a PhD student in insect biology. She works at the University of California, Riverside.



Laura Figueroa watches as meat-eating bees swarm a piece of rotting chicken in the Costa Rican jungle. Despite being a vegetarian, this PhD student helped string up the meat. She was part of a research team that examined the insects guts.Credit: Q. McFrederick



To study these bees, she worked with a team of scientists who travelled to the Central American nation of Costa Rica. In its jungles, vulture bees usually feed on dead lizards and snakes. But theyre not too picky. These bees will eat any dead animal. So the researchers bought some raw chicken at a grocery. After cutting it up, they suspended the flesh from branches in the trees. To deter ants, they smeared the string it dangled from with petroleum jelly. 





The funny thing is were all vegetarians, says entomologist Quinn McFrederick, who also works at UC-Riverside. Entomologists are scientists who study insects. It was kind of gross for us to cut up the chicken, he recalls. And that gross factor intensified pretty quickly. In the warm, humid jungle, the chicken soon rotted, turning slimy and stinky.



But the bees took the bait within a day. As they stopped by to dine, the researchers trapped some 30 of them in glass vials. The scientists also captured another 30 or so of two other types of local bees. One type feeds just on flowers. Another type dines mostly on flowers but sometimes snacks on rotting meat. Central and South America are home to all three types of these stingless bees.



The bees were stored in alcohol. This immediately killed the insects but preserved their DNA. It also preserved the DNA of any microbes in their guts. This allowed the scientists to identify what types of bacteria they hosted.



Microbes live in the guts of animals, including people. Certain of those bacteria can help break down food. They also can protect animals from some toxin-producing bacteria which often live on rotting meat.



The guts of vulture bees had a lot more of a particular type of bacteria than did vegetarian bees. Those bacteria are similar to ones found in the intestines of vultures and hyenas. Like vulture bees, these animals, too, feed on rotting meat.



Maccaro and her teammates described their new findings November 23 in the journal mBio.





Acid protection against rotten meals



Certain bacteria make the guts of vultures and hyenas very acidic. This is important because acid-producing bacteria kill toxin-producing bacteria in rotting meat. In fact, these microbes keep vultures and hyenas from getting sick. It probably does the same thing for the meat-eating bees, Maccaro and her team now conclude.



The meat-eating bees had between 30 and 35 percent more acid-producing bacteria than the strictly vegetarian bees. Some types of the acid-making microbes showed up only in the meat-eating bees.



Acid-producing bacteria also reside our intestines. The human gut doesnt, however, have as many bacteria as do the guts in vultures, hyenas or meat-eating bees. That may explain why the bacteria on rotting meat can give people diarrhea or make us throw up.



Maccaro says its hard to know which evolved first the gut bacteria or the bees ability to eat meat. But, she adds, its likely the bees turned to meat because there was so much competition for flowers as a food source.



Two types of vulture and a stork dine on a carcass in Kenyas Maasai Mara National Reserve. High levels of acid-making microbes in the gut of such carrion-feeders can kill otherwise sickening bacteria in rotting flesh. Similar acid-making microbes appear to aid meat-eating bees, a new study finds.Anup Shah/Stone/Getty Images Plus



The role of a meaty diet



David Roubik is the evolutionary ecologist who described how meat-eating bees find and devour their meals. He works for the Smithsonian Tropical Research Institute in Panama. Scientists knew the bees were collecting meat, he says. But for a long time, he adds, nobody had the foggiest idea that the bees were actually consuming flesh.



People had thought the bees somehow used it to make their nests.



He showed, however, that they were actually eating flesh, biting into it with their sharp mandibles. He described how once the bees find a dead animal, they deposit a trail of pheromones signaling chemicals on plants along their flight back to the nest. Their nest mates then use these chemical markers to track down the carcass.



A large dead lizard placed 15 meters [about 50 feet] from one nest was located by bees within eight hours, Roubik reported in a 1982 Science paper. It described some of his research in Panama. Groups of 60 to 80 bees removed the skin, he says. After then entering the body, they reduced much of the carcass to a skeleton during the next 2 days.



The bees consume some of the meat for themselves. They regurgitate the rest, storing it in their nest. There it will serve as a food source for developing bees.



The large numbers of acid-loving bacteria in the vulture bees guts end up in this stored food. Otherwise, destructive bacteria would ruin the food and release enough toxins to kill the colony, says Roubik.



Meat-eating bees also make surprisingly good honey by turning partly digested dead animal material into sweet honey-like glucose, observes Roubik. I have tried the honey a number of times, he says. It is sweet and delicious.

A raremanuscriptco-authored byGerman-American physicistAlbert Einstein and Swiss-Italian engineer Michele Bessojust became themostexpensiveautographed scientific paper ever sold.The final price which added up to more than13.3 million euros ($15 million)with fees far exceededthe3.5 millionEuros ($3.9 million)expectedbyChristie's Auction House Parisoffice, which hosted the sale.

Excess nutrients, such as nitrogen and phosphorus, can harm coastal ecosystems. In the past researchers have mostly focused on excess nutrients from farms, usually from fertilizer that runs off fields instead of sticking around in the soil. Now, a new model explores the global impact of nitrogen from sewage and finds that nutrients in our poop and pee are also causing harm.



Explainer: The fertilizing power of N and P



Coastal areas face dangers ranging from climate change to overfishing to pollution. And sewage may pile on to these problems. An influx of nutrients can lead to eutrophication. That process causes oxygen levels in the water to drop to low levels that can kill fish and other creatures.



Coral reefs and seagrass beds are important ecosystems that are home to many creatures. Researchers at the University of California, Santa Barbara wanted to explore which coastal areas receive the most nitrogen and determine the risks to these key ecosystems. So they created a computer model.





However, theres a lot scientists dont know about the flow of nutrients from sewage into the ocean. And what they do know isnt spread evenly around the world. For example, researchers have more data on nutrients from sewer systems. But many places lack sewers.





To get past that data shortage, the researchers looked at what people eat. Protein from food is a major source of nitrogen in wastewater. The scientists used protein consumption and population size and density to calculate how much nitrogen people excrete in various locations. They then accounted for how wastewater treatment removes nitrogen.



The researchers combined this data with a high-resolution map of watersheds worldwide. That showed where the nitrogen flows. Overall, wastewater dumps 6.2 teragrams (13.7 billion pounds) of nitrogen into the ocean, according to the model. Thats equal to about 40 percent of the nitrogen that comes from agriculture, the scientists report November 10 in Plos One.  



The new results suggest that 58 percent of coral reefs and 88 percent of seagrass beds receive wastewater nitrogen. And the model allows researchers to zoom in on specific areas. This could help guide conservation efforts, the authors suggest.




Coral reefs and seagrass under threat



These maps show where nitrogen may threaten coral reefs (A) and seagrass (B). (Use the arrows at left and right to switch between the images). They are based on a computer model that researchers developed. The model simulates how nitrogen gets into coastal environments. First, the model estimates how much nitrogen ends up in sewage based on what people eat and where they live. Then it adjusts the nitrogen levels in the sewage based on wastewater treatment. Finally, using a very detailed map of the worlds watersheds, the model simulates how the nitrogen flows out to sea. These maps take results from the model and label whether nitrogen concentrations are high (High wastewater impact) or low (No wastewater impact) at areas with corals (A) and seagrass (B). Click here to see both graphs in one image.



Tuholske et al/Plos One 2021 (CC BY 4.0)Tuholske et al/Plos One 2021 (CC BY 4.0)




Data dive:



Open up a visualization of the model here. Its easiest to see the nitrogen data when Dark mode is selected. Make sure theres a check mark next to Location Names and Nitrogen Plumes. Zoom in on the coastal area closest to where you live. What is the concentration of the nitrogen there?Can you find any places that receive 100,000,000 grams of nitrogen/year? (Hint: you may have to zoom in a lot.) How about 1,000,000,000 grams?Check the box next to Nitrogen Source. What do you notice about the places that light up?Look at Map A above. Some areas are hotspots for coral wastewater impact. These have lots of red dots clustered together. Where are these areas? What do they have in common?Where are corals less likely to experience risks from nitrogen?Look at Map B. What are hotspots for seagrass wastewater impact?Where is seagrass less likely to experience risks from nitrogen?

Hunting for aliens might sound like science fiction. But it’s a serious science. Alien-seeking researchers don’t chase down UFOs, though. Some use telescopes to listen for messages broadcast by alien civilizations. Others peer at distant words for evidence of life.



No aliens have been found yet. But it’s a big universe. Astronomers have found thousands of planets orbiting other stars. And there may be billions more worlds still to be discovered. Some may even have moons that can support life. That’s a lot of potential alien real estate. Over the last 60 years, astronomers have scoured only a tiny bit of it for interstellar messages. The area searched so far is like a hot tub’s worth of water out of all the world’s oceans.



See all the entries from our Lets Learn About series



Some people think we’d have a better chance of meeting aliens if we introduce ourselves. That is, beam our own messages into space. These messages could be written in mathematical patterns. (Math is thought to be a universal language.) One such message was sent from the Arecibo telescope in Puerto Rico in 1974. But other scientists say this is a bad idea. We might not want to advertise our existence to unfriendly aliens.





There may also be aliens that aren’t able to send or read messages. Some planets may be home to simple, even microscopic life forms. To find those worlds, astronomers look for new worlds in the so-called habitable zone. This is the area around a star where a planet would be just warm enough to have liquid water. That’s important because water is essential for all known life. One such planet may orbit the nearest star to our sun.



A planet may not have to look just like Earth, though, to be a good home for aliens. Some hardy creatures on our own planet thrive in seemingly unlivable conditions. Microbes at the seafloor bask in scalding water. Meanwhile, microbes nestled in Antarctic ice withstand freezing cold. Other critters slurp up toxic chemicals or bathe in acid. Learning about these “extremophiles” broadens our view of what places in the cosmos might be livable.





Microbial aliens might also be found closer to home. Saturn’s moon Enceladus is a good place to look. So is Jupiter’s moon Europa. Both have oceans of liquid water encased in their icy crusts. Mars could even host life in a lake near its south pole. A recent survey suggested that most Americans would welcome finding alien microbes.



The question of whether we are alone in the universe has captured peoples imaginations for millennia. And the answer has two equally mind-blowing possibilities.  In all the vast expanse of outer space, either we are completely alone or we are not.



Want to know more? Weve got some stories to get you started:



Worlds deepest zoo harbors clues to extraterrestrial life Scientists have found a wide range of life deep below Earths surface. Those discoveries could inform the search for life on other planets. (6/15/2017) Readability: 6.6



Only a small fraction of space has been searched for aliens How little? A volume equivalent to a hot tubs worth of the Earths oceans. (10/24/2018) Readability: 8.2



Should we call out to space aliens? To speed up the search for extraterrestrials, some scientists recommend sending signals to space. Others disagree. (3/21/2017) Readability: 8.0





Heres how astronomers can tease out what gases exist in an exoplanets atmosphere and find clues about whether that world might be habitable.



Explore more



Scientists Say: Exomoon



Explainer: What is a planet?



Lets learn about exoplanets



Profile: Looking for life beyond the solar system



Keeping space missions from infecting Earth and other worlds



Finding living Martians just got a bit more believable



Most Americans would welcome a microbial E.T.



Will we know alien life when we see it?



A trail of cosmic dust may lead to alien life



Planets with hydrogen skies could harbor life



Cool Jobs: Reaching out to E.T. is a numbers game



Activities



Word find



The message to alien civilizations sent out by the Arecibo Radio Telescope in 1974 was a picture. It included a basic sketch of a person, the solar system and other information. But in order to beam that picture into space, scientists had to translate it into binary code. Thats a series of 1s and 0s. Learn how to read and create your own binary code messages with this activity from the Rio Tinto Alcan Planetarium in Montreal, Canada.

Explorers from Europe made their home in North America longer ago than we had realized. Vikings settled in Canada exactly 1,000 years ago, a new study finds. Details preserved in wood were key to the discovery.



Researchers had evidence that Norse Vikings built the structures and lived there roughly 1,000 years ago. But until now, they hadnt been able to find an exact date for the settlement.



Newfoundland is part of Canadas easternmost province. A team of scientists examined wooden objects at a site on site on its northern coast. By counting tree rings preserved in the wood, they discovered that the objects were made from trees cut down in the year 1021. That gives the oldest precise date for Europeans in the Americas.



Indeed, its the only one from before Christopher Columbus and his ships came to North America in 1492. Margot Kuitems and Michael Dee are geological scientists who led the study. They work at the University of Groningen in the Netherlands. Their team shared its findings October 20 in Nature.





The site where archeologists found the wooden objects is known as LAnse aux Meadows. Thats French for meadow cove. Discovered in1960, it is now a historic site protected as part of the United Nations Educational, Scientific and Cultural Organization. The Newfoundland site hosts the remains of three houses and other structures. All were made from local trees.





Signature spike



The new study focused on four wooden objects found at LAnse aux Meadows. Its not clear how the objects were used, but each had been cut with metal tools. On three of the finds, Kuitems, Dee and their team identified an annual growth rings in the wood that showed a signature spike in radiocarbon levels. Other researchers have dated that spike to the year 993. Thats when a surge of cosmic rays from solar activity bombarded Earth and increased the planets atmospheric levels of radioactive carbon.



The scientists used the signature spike to help them count the growth rings in each of the wooden objects. Each year that a tree lives, it adds a ring of woody tissue around the outer layer of its trunk. Counting those rings would tell the researchers when the tree was cut down and used to make the object. They started at the year 993 ring and worked their way out to the edge. All the objects yielded the same year 1021.



Despite its precision, that date doesnt answer the question of when Vikings first set foot in the Americas. Some scientists believe LAnse aux Meadows might have been part of a larger area in eastern Canada called Vinland. That region is described in 13th century Icelandic texts as having been settled by Vikings.

Experiment (noun, Ex-PAIR-uh-ment)



The word experiment might make you think of scientists wearing white coats in a lab. But anyone, anywhere can do an experiment. An experiment is a procedure used to test an idea about the world.



In an experiment, a person manipulates one thing and observes how that may affect another thing. The thing that the person manipulates is the independent variable. The thing that may change in response is the dependent variable.





For example, Science News for Students did an experiment to test the five-second rule. The rule states that food dropped on the floor will collect fewer germs if its picked up quickly. To test this rule, you need to compare two things: how long food lays on the floor, and how germy the food gets. In this case, the person doing the experiment manipulates the amount of time the food spends on the floor. How long the food lays on the floor is the independent variable. The dependent variable the thing that may change in response is how dirty the food gets.



Measurements of the number of germs on different pieces of food are experimental data. Analyzing data can lead to a conclusion about the idea being tested. In this experiment, the data suggest that time spent on the floor does not affect how many germs get on food. Conclusion: the five-second rule is a myth.



But don’t take our word for it. A crucial part of science is replication. Thats when many scientists do the same experiment to confirm or deny the results. Join the scientific process by doing the five-second rule experiment for yourself. Or try another experiment from our collection.



In a sentence



If you have a question, like which parts of the body are most sensitive to touch, an experiment can help you find out the answer.



Check out the full list of Scientists Say.