“We should start focusing on how to prevent the tsunami,” says 14-year-old Anudeep Gosal of Orlando, Fla. His teammates, all 12-to-14-year-olds, are drawing on a dry-erase board and experimenting with ways to block the giant wave. The clock keeps ticking.

Caption: Members of the red team construct a “beach” in a water tank as part of a tsunami simulation.

Emily Sohn

“There’s 7 minutes and 49 seconds to finish this thing,” Anudeep says. He shakes his head, grabs a handful of plastic zip ties, and runs to the water’s edge.

Can a teenager in jeans and a gray T-shirt stop the destructive power of a massive wave with just a bundle of plastic strips and the help of his friends? The answer is: No.

Luckily, this nightmare is just a simulation. Figuring out how to tame a tsunami’s destructive power was one of six 90-minute problems presented to finalists at this year’s Discovery Channel Young Scientist Challenge (DCYSC).

Every year, DCYSC brings the nation’s top 40 middle-school science-fair winners to Washington, D.C., to compete for thousands of dollars in scholarship money, dream science trips, and other prizes. Students work in teams of five, but judges score them individually on their ability to cooperate, communicate, and think through problems. As deadlines loom, Discovery Channel interviewers and cameramen push their way into the action.

Tsunami science

In “Tsunami Science,” the grey team’s first challenge, finalists faced a 40-foot-long tank that was 5 inches wide and filled about halfway along its length with 10 inches of water. A nearby table held strips of sheet metal, plastic boxes, wooden boards, and various tools.

First, finalists had to figure out how to create waves at one end of the tank. The grey team did it by sliding a big box into the water. Other teams used a paddle. Teams also had to make sure each wave they made was the same so that they could measure how high the water splashed at the other end. Splash height represented the wave’s power to destroy.

Blue team members use a board to create a wave powerful enough to reach the opposite end of the water tank.

DCYSC

“If we were small people in that tank, we’d feel so helpless,” said red team member Taylor Jones, who’s from Maryville, Tenn.

With these imaginary little people in mind, teams then had to work out how to tame the tsunami by building fake beaches or other types of terrain that would absorb its impact. Before their 90 minutes were up, teams needed to film a 3-minute newscast to explain their findings.

Creating the video was just as important as solving the problem, says head judge Steve “Judge Jake” Jacobs.

“We don’t have enough science communicators,” he says. “That’s why people are scared of all this stuff.”

Eye of the storm

Averting disaster and alleviating fear came up a lot at DCYSC this year. Its official theme was “Forces of Nature,” and most challenges involved dangerous situations that occur in the natural world.

In “Eye of the Storm,” for instance, teams had to create a tornado by positioning fans around a platform. Smoke came out of a hole in the floor, while a 600-pound fan sucked air upwards from a height of 30 feet. If finalists set the direction and power of the fans just right, they could create a tall, spiraling funnel cloud.

Members of the orange team have to adjust fans to turn a stream of smoke into a tornado-like funnel cloud.

Emily Sohn

Over at “Into the Thick of It,” meanwhile, finalists experienced what airplane pilots see when they have to land in thick fog. In a 16,000-square-foot test chamber filled with mist, teams compared differently colored boards to see which ones were most visible. (Yellow and white, it turns out, worked best).

Standing up to the forces of nature showed students that understanding the science behind tsunamis, hurricanes, tornadoes, and thick fog can help us protect ourselves, even if we can’t prevent them from forming in the first place.

Emergency workers

Recent disasters have also shown that just being prepared for a disaster isn’t enough. Injuries and deaths still happen.

And so, “In Case of Emergency” challenged finalists to act as emergency workers and clean up a pile of toxic medical waste, including bloody gauze pads, gooey pus, and amputated body parts. The objects were fake, but they looked nauseatingly real and smelled gross.

In one challenge, DCYSC finalists had to clean up a pile of toxic medical waste.

Emily Sohn

“Where are we going to put the bloody hand?” asked blue team member Aaron Rozon of Hawaii, as he poured a package of potato chips over it. He wanted to use the plastic bag as a wrapper for waste. Wiping his hands on his apron, he added, “I’m totally covered in this stuff.”

When the judges used a black (ultraviolet) light to reveal how completely contaminated everyone was, 14-year-old Neela Thangada of Texas looked disappointed. “We should’ve had a plan,” she said. “With division of labor, we would’ve done a much better job.”

Elijah Mena and Anudeep Gosal use ordinary table salt while trying to separate unknown substances in a mixture.

DCYSC

Teams discovered that planning ahead was important for all the challenges. Simply jumping into problems and trying to solve them through trial and error could quickly lead them off track. Making and testing hypotheses worked much better.

Talking and thinking

Communication also emerged as a major asset. The yellow team, for example, found out during the tornado challenge that their quietest member, Garrett Yazzie, also had some of the best ideas.

“I don’t talk a lot,” says Garrett, who’s from Pinon, Ariz. “I’m more of a thinker.”

Once his team recognized the nature of their group dynamics, they were more willing to listen when Garrett spoke. “Soft voice, loud voice,” said Shireen Dhir of Georgia, “as long as you get your idea across, that’s what matters.”

As finalists gained confidence in their ability to think like scientists and communicate ideas, their fear of natural disasters seemed to slip away.

Camden Miller and Nilesh Raval of the green team watch their team’s tornado.

DCYSC

At home in Florida, Heather Foster, 15, has seen a number of frightening hurricane-caused tornadoes. Watching the tornado that she helped create, however, made her giddy.

“This is fun,” Heather said. She hopped and clapped every time a funnel formed. “Next time it might make me want to run up to a tornado and see it, because this is really cool.”

For the record, if a real tornado comes your way, head for the basement. Unless you’re on the set of a Discovery Channel event, the eye of a storm is not a safe place to be.

Going Deeper:

News Detective: A Tornado Challenge

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Word Find: DCYSC 2005

Scientists have recently tackled these questions. They found that when a person is looking at your face, she might not believe what she sees if your body language doesn’t match the feeling that your face shows.

To find out how a person’s body language affects the emotional impression given by that person’s face, scientists used pictures in which body posture matched (left) and didn’t match (right) facial expression.

Proceedings of the National Academy of Sciences

Studying such mixed messages is nothing new for scientists. Previously, they had found that the tone of a person’s voice can be more important than the words that are spoken. For example, most people tend not to believe a person who says in a flat voice, “I’m so excited.”

When it came to emotions conveyed by facial expressions and body language, most scientists suspected that the face was more important. To test if this was true, psychologists from the Netherlands and Boston showed people a number of pictures of isolated faces and isolated bodies (with faces blurred out) that showed anger or fear. They also showed pictures in which angry or scared faces were paired with angry or scared bodies.

An angry face had low eyebrows and tight lips. A scared face had high eyebrows and a slightly open mouth. An angry body had arms back and shoulders at an angle, as if ready to fight. A scared body had arms forward and shoulders square, as if ready to defend.

Using the pictures, the researchers asked people to quickly press a button that matched the correct facial emotion: anger or fear. When people looked only at faces, they chose the right emotion about 81 percent of the time. But when people looked at a mismatched picture—a scared face with an angry body, for example—they correctly guessed the emotion on the face only 64 percent of the time.

These results told the researchers that mixed signals can confuse people. Even when people pay attention to the face, body language subtly influences which emotion they read.

So, your body language is important for telling people how you feel. And if you want to be understood, it helps to avoid sending mixed messages.—K. Greene

Going Deeper:

Greene, Katie. 2005. Read my gestures: Body language can trump facial expressions. Science News 168(Oct. 29):278. Available at http://www.sciencenews.org/articles/20051029/fob7.asp .

The news isn’t all gloom and doom, however. Scientists working along the southeastern coast of India have found that trees appear to protect seaside settlements from the worst effects of a tsunami.

The December 2004 tsunami knocked down casuarina trees next to the Indian Ocean but left trees farther inland—and the villages behind them—standing.

V. Selvam/Science

When a massive tsunami swept through Asia last winter, it caused massive destruction. Villages surrounded by trees, however, suffered far less damage than did villages without protective forests.

Scientists have long suspected that mangroves (trees that grow in the water along the coast) protect the land nearby. To test this idea, ecologists started collecting data last Dec. 27, the day after the big tsunami struck.

They chose to focus on a 21-kilometer (13-mile) stretch of coast in Cuddalore, India. This stretch was perfect for the study because it was straight and uniform, so waves hit every part of it with about the same amount of force.

Other places were hit harder than Cuddalore, but the 4- to 5-meter (13- to 16-foot) waves that swept into Cuddalore were big enough to destroy two villages. Three other villages survived. The only difference was that the first two had no protective mangroves nearby, while the other three had hundreds of meters of mangroves between them and the ocean.

A few kilometers away, some other villages were surrounded by land-dwelling trees called casuarinas. The trees had been planted after a cyclone 20 years ago. These settlements survived, too, with little damage.

Healthy mangroves also emerged from the tsunami in much better shape than mangroves that had been harmed by people.

The research is important because mangrove forests have been disappearing. People use the wood and destroy the trees to make room for crops and create shrimp farms and fishponds.

Protecting and restoring the world’s coastal forests could be the secret to survival when future tsunamis strike.—E. Sohn

Going Deeper:

Harder, Ben. 2005. Breaking waves: Mangroves shielded parts of coast from tsunami. Science News 168(Oct. 29):276-277. Available at http://www.sciencenews.org/articles/20051029/fob3.asp .

You can learn more about mangrove trees at www.epa.gov/owow/wetlands/types/mangrove.html (U.S. Environmental Protection Agency) and www.naturia.per.sg/buloh/plants/mangrove_trees.htm (Chek Jawa, Singapore).

Sohn, Emily. 2005. Unnatural disasters. Science News for Kids (Sept. 21). Available at http://www.sciencenewsforkids.org/articles/20050921/Feature1.asp .

______. 2005. Saving wetlands. Science News for Kids (April 6). Available at http://www.sciencenewsforkids.org/articles/20050406/Feature1.asp .

______. 2005. Wave of destruction. Science News for Kids (Jan. 19). Available at http://www.sciencenewsforkids.org/articles/20050119/Feature1.asp .

______. 2005. Digging into a tsunami disaster. Science News for Kids (Jan. 12). Available at http://www.sciencenewsforkids.org/articles/20050112/Note2.asp .

______. 2004. Recipe for a hurricane. Science News for Kids (Sept. 29). Available at http://www.sciencenewsforkids.org/articles/20040929/Feature1.asp .

______. 2004. An ocean view’s downside. Science News for Kids (March 31). Available at http://www.sciencenewsforkids.org/articles/20040331/Note2.asp .

Over the years, the long-armed creatures have gained mythical status. Authors have written about them. Artists have painted them.

This drawing of a giant squid was based on a specimen found on the coast of Newfoundland in 1874.

NOAA Photo Library

As myths go, however, giant squid are unusual because they actually exist. Sixty-foot-long specimens have washed up on beaches around the world. But the animals have always been dead by the time they appeared on shore.

Determined to find giant squid alive and in their home waters, a small but dedicated group of scientists has been aggressively scouring the deep sea for many years.

“For reasons we’re not quite sure of, we haven’t been able to find this guy alive,” says Lou Zeidberg, a marine biologist at the Monterey Bay Aquarium Research Institute in Moss Landing, Calif.

Until now. A group of Japanese scientists recently caught one of the elusive creatures on film. With an underwater camera, the team followed a 26-foot-long giant squid at a depth of 3,000 feet near Japan’s Ogasawara Islands.

A giant squid goes for a baited fishing line.

Courtesy of Tsunemi Kubodera and Kyoichi Mori

The photos—about 550 in all—show the giant squid lunging for bait, getting stuck, and losing one of its tentacles.

Skin displays

Giant squid, known to scientists as Architeuthis, is just one of some 700 species of squid, which belong to a larger group of animals called cephalopods. The group also includes octopuses, cuttlefish, and the nautilus.

Cephalopods are a compelling collection of creatures to study, Zeidberg says, because there’s a lot to learn about them. For one thing, they have special cells in their skin that can change color almost instantly to create elaborate patterns and displays.

A small squid known as Illex illecebrosus cruises over a sandy area of the seabed.

William Millhouser, NOS/NOAA Photo Library

“People spend a lot of money creating light shows to come close to what cephalopods can do naturally,” Zeidberg says.

Cephalopods also have highly developed eyes, similar to ours. They have long tentacles extending from their bodies. And they’re one of the few animals in the world that use jet propulsion to move. They squirt water out of their bodies in one direction in order to move in the opposite direction.

“When you see them dead in a fish market, they’re kind of disgusting,” Zeidberg says. “When you see them alive, they’re just amazing. I could stare at them forever.”

Diversity

Among squid, Architeuthis gets most of the public’s attention thanks to its size. Scientists, however, are probing the startling diversity within the squid world. There are squid so small that babies are the size of a grain of rice, and adults grow to be just 6 inches long. Jumbo squid are about 6 to 10 feet long. Giant squid can reach 60 feet. Other species fit somewhere in between.

Zeidberg and his coworkers have been catching squid to study in the lab. They want to know how much fish squid eat, how fast they swim, how much oxygen they use, how their color-changing cells work, and why their ranges have been spreading in some places but shrinking in others.

This year, for example, was a bad one for squid in California, Zeidberg says. That’s a problem because fisheries in California usually catch more squid than anything else, he says. Most of the catch gets sold to China and Japan. The rest is eaten here as calamari.

Squid for sale in a Japanese market.

Dr. Roger Mann, VIMS/NOAA Photo Library

Squid fishing is a multimillion-dollar industry. So, learning more about the animals might help scientists regulate squid numbers and prevent expensive losses.

Light attraction

Most types of squid are easy to spot in the wild because they regularly come to the surface, and they’re attracted to the lights on cameras that researchers use. “Jumbo squid just love us,” Zeidberg says. “They use our lights to hunt other animals.”

Giant squid are much harder to see. For one thing, they live at extreme depths, where the environment is cold and harsh. The only practical way for people to get a glimpse of what’s down there directly is with remotely operated vehicles (see “Explorer of the Extreme Deep“).

Such vehicles, however, are not ideal for squid hunting. They’re expensive to operate. They’re noisy. Their lights are blindingly bright. And they move at only a few miles per hour, Zeidberg says. Giant squid, on the other hand, can probably swim up to 15 miles per hour.

“Architeuthis lives its whole life in the deep sea,” he says. “When it sees something bright and doesn’t know what it is, it probably doesn’t want to find out.”

Knowing that sperm whales feed on giant squid, Japanese researchers started setting out cameras where whales gather near islands south of Japan. The scientists dangled the cameras above hooks baited with small squid and mashed shrimp.

On Sept. 30, 2004, one of these cameras recorded the pale form of a giant squid as it attacked the bait. Giant squid have eight arms plus two extralong tentacles. The photographed creature wrapped the ends of its paired tentacles around the bait, and one tentacle snagged on the hook. The camera caught images of the squid fighting to free itself.

The photographed giant squid lost part of one of its tentacles before it escaped. This tentacle section was then hauled to the surface.

Courtesy of Tsunemi Kubodera and Kyoichi Mori

After more than 4 hours, part of the tentacle tore off, and the squid vanished. When the tentacle section was hauled to the surface, its suckers could still grab the boat and even people’s fingers.

Inspiring images

By bringing attention to squid, the images of a live giant squid may inspire people to care more about the animals, their relatives, and the oceans they live in, Zeidberg says.

At the same time, actually finding something that has been sought for so long may have a downside, too. “When a mystery finally gets solved, there’s one less thing to wonder about,” Zeidberg says.

Perhaps that’s what author John Steinbeck meant in his 1941 book The Log from the Sea of Cortez. “Men really need sea monsters in their personal oceans,” Steinbeck wrote. “An ocean without its unnamed monsters would be like a completely dreamless sleep.”

Going Deeper:

Additional Information

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Word Find: Giant Squid

Get used to the idea. Living gadgets may be on their way.

A bacterium coated with tiny gold particles.

© Angewandte Chemie/Wiley

Two chemical engineers from the University of Nebraska in Lincoln have turned simple bacteria into electrical devices that measure humidity. The craziest part of all is that the bacteria must be alive for the gadgets to work at first. After they get going, the sensors work even when the tiny microbes die.

To build the devices, the researchers started with a basic electrical device called a silicon chip. The chip contained gold electrodes, which are good at conducting electricity.

Next, the engineers grew a coating of a type of bacteria called Bacillus cereus. These microbes grouped together and formed bridges between the electrodes. Finally, the researchers dipped the chips into a solution that contained minuscule gold beads with a coating that made them stick to the bacteria.

Coated with gold particles, these rodlike bacteria act as a living humidity sensor. The top and bottom bars are electrodes.

© Angewandte Chemie/Wiley

To test their living sensors, the researchers passed electricity through the gold beads on the backs of the microbes that formed bridges. When humidity drops (which means that moisture levels in the air go down), the bacteria shrink. The distance between beads then decreases, so more electricity flows.

This humidity detector is extremely sensitive. Lowering humidity from 20 percent to zero causes 40 times as much electricity to flow across the bridge.

Now that researchers have figured out how to make a sensor out of living bacteria, they have set their sights on other devices. In the future, they hope to hitch microbes to electronic devices so that feeding these tiny captives results in a flow of electricity from the critters into the devices. Maybe microbe-powered batteries will someday run the really tiny iPods that your kids will use.—E. Sohn

Going Deeper:

Weiss, Peter. 2005. Bionic bacteria: Gold nanoparticles make gadgets of living microbes. Science News 168(Oct. 22):259-260. Available at http://www.sciencenews.org/articles/20051022/fob2.asp .

Other animals are known for their slowness. Sloths move only when they have to. Snails edge along at a glacial pace.

A sea lily, or stalked crinoid, rests on the seafloor. About 5 inches (13 centimeters) across, this animal uses its feathery crown to capture food.

National Oceanic and Atmospheric Administration

Now, sea animals known as stalked crinoids have joined the ranks of those that can run.

Crinoids, also called sea lilies, are relatives of starfish and sea urchins. They live on the seafloor, and they spend most of their time standing around and catching food. Stalked crinoids look like flowers because they have feathery arms arranged in a circle on top of a long stalk.

Scientists have known for a while that some stalked crinoids move. But they usually creep along so slowly that it’s hard to tell they’re actually going anywhere. Previously, researchers aboard submersibles had noticed that crinoids appeared in different positions from dive to dive. Still, the creatures had never been measured moving faster than about 0.6 meter per hour (2 feet per hour).

A stalked crinoid can move as fast as 140 meters per hour.

Tomasz Baumiller and Charles Messing

Now, analysis of an old video has revealed a record-breaker. In the 1990s, a submersible off Grand Bahama Island filmed a stalked crinoid moving at a speedy 140 meters per hour (459 feet per hour). The video was taken at a depth of about 400 meters (1,300 feet). It showed the creature lying on the bottom, pulling itself along with its arms. It’s the sort of crawling you might do using your elbows to pull you along.

Researchers suspect that crinoids “run” to get away from hungry predators.

What’s next—scampering mushrooms?—E. Sohn

Going Deeper:

Milius, Susan. 2005. Great galloping crinoids: Lilylike sea animal takes a brisk walk. Science News 168(Oct. 22):261-262. Available at http://www.sciencenews.org/articles/20051022/fob6.asp .

To see a movie of a stalked crinoid in motion, click here.

You can learn more about stalked crinoids (sea lilies) and their relatives at www.ucmp.berkeley.edu/echinodermata/crinoidea.html (University of California, Berkeley), www.nova.edu/ocean/messing/crinoids/w3introduction.html (Nova Southeastern University), and tolweb.org/tree?group=Crinoidea&contgroup=Echinodermata (Tree of Life Project).

Twice a year, however, many people must make an adjustment for daylight saving time (DST). In the spring, they have to set their clocks forward 1 hour. In the fall, they have to turn them back 1 hour.

There are lots of different ways to find out what time it is.

In most of the United States, DST presently begins on the first Sunday in April. It ends on the last Sunday in October, when clocks return to official standard time. That’s about to change. In 2007, according to a law passed earlier this year, DST for most of the United States will begin 3 weeks earlier—on the second Sunday in March. And it will end 1 week later—on the first Sunday in November.

The change may sound minor, but the difference will be noticeable in our experience of dark and light and, some experts say, in the size of our energy bills and in our impact on the environment.

Extending DST will mean that winter mornings will be darker for a while, but late afternoons with daylight will last longer into fall and start earlier in spring. “There’s hope that there will be more time when daylight overlaps with normal activities,” says Tom O’Brian. He heads the time and frequency division at the National Institute of Standards and Technology (NIST) in Boulder, Colo.

A lot of people are up and about in the late afternoon, the idea goes, so we’ll probably use less energy for lighting if there’s more daylight during those hours. That would be better for both the environment and our pocketbooks.

Earth’s tilt

We tend to take for granted the way we measure time. A day has 24 hours, divided into 1,140 minutes or 86,400 seconds. Each day begins and ends at midnight.

As natural as the system seems, however, there’s little that’s natural about it. Although the length of a day is set by the time it takes Earth to make a complete rotation on its axis, 24 hours, 60 minutes, and 60 seconds are simply numbers and units that people chose long ago to measure the passage of time. We could just as easily have days with 117 short hours or 15 very long minutes. Or, we could set our clocks so that it gets light at midnight and dark at 8 a.m.

The fact that a minute has 60 seconds, as shown on this stopwatch, was a choice made by people long ago.

To prevent confusion, governments worldwide have gotten together to standardize the way we tell time and to establish a system of time zones. In the United States, the National Institute of Standards and Technology (NIST) keeps an extremely accurate clock that sets an official time for the whole country and keeps us in sync with the rest of the world.

Earth is tilted in relation to its orbit around the sun. As a result, winter days have fewer hours of sunlight than do summer days in the northern and southern hemispheres. On the equator, days and nights are the same length, all year round. The further north or south you go from the equator, the bigger is the seasonal difference in hours of daylight.

DST began as a way to save energy by matching daylight hours during different seasons with people’s typical schedules. Nowadays, countries in different parts of the world often have different rules about when it starts and ends and how big the time change is. In Australia and other parts of the southern hemisphere, where summer arrives in December, DST runs from October to March.

Countries that lie close to the equator typically don’t observe DST because daylight hours in these regions are similar all year. For this reason, clocks are also not changed in Hawaii, American Samoa, Guam, Puerto Rico, and the Virgin Islands. There are also exceptions, for other reasons, for part of the state of Indiana and most of Arizona.

Up and about

In the summer where I live in Minnesota, the sun comes up at 5:30 a.m., long before we wake up, and it can stay light as late as 10:30 p.m. We hardly ever have to turn on the lights at home.

When winter comes, however, it’s usually dark when we get up and dark by the time we get home, so we end up using more electricity.

The arrival of daylight saving time in the spring means that some kids end up having to wait for the school bus when it’s still dark out.

Shifting the clock forward 1 hour makes it seem as if we’ve moved an hour of daylight from the morning to the evening. In this case, 6 a.m. is suddenly what 7 a.m. was before. In other words, DST makes it appear as if the sun rises later and sets later. The arrival of DST in the spring means that some kids end up waiting for the school bus while it’s still dark out, but afternoons and evenings have more sunlight.

The whole system emphasizes the power that time has gained over us, O’Brian says. “Hundreds of years ago, hardly anyone had a clock,” he says. “They based the day on when the sun rises and sets. We don’t do that anymore. We’re driven by the clock, and we try to make the sun rise when we want it to.”

Energy use and the demand for electricity for lighting are directly connected with when we go to bed and when we get up. In a typical home, 25 percent of all electricity is used for lighting and small appliances, such as TVs, VCRs, and stereos. Much of that use occurs in the evening. When we go to bed, we turn off lights and TV. By moving the clock ahead 1 hour and taking advantage of daylight, we can cut the amount of electricity that we use later in the day.

Saving energy

In 1973, as an energy-saving measure, the U.S. Congress passed a law temporarily extending DST. In 1974, DST lasted 10 months, and, in 1975, it lasted 8 months instead of the usual 6 months. The U.S. Department of Transportation studied the effect of these changes and estimated that observing DST in March and April reduced electricity use by about 1 percent, saving the equivalent in energy of 10,000 barrels of oil each day.

The study also found that, because more people traveled home from work and school in daylight, having DST in March and April apparently saved lives and reduced traffic accidents.

At present, daylight saving time for most of the United States begins at 2 a.m. on the first Sunday in April.

Newer studies, however, have challenged these claims. And times have changed. So, some people aren’t sure that extending DST nowadays will actually save energy. With many more people using air conditioning during warm afternoon hours, for example, increased energy use for air conditioning may outweigh decreased energy use for lighting.

Extending DST also worries people for other reasons. The change would put the United States out of step with Canada and Mexico, its North American neighbors. Airlines flying to those countries would have to make schedule adjustments not only for time zone changes but also for differences in DST.

There are also safety concerns. The late sunrise in the spring would mean that children might be traveling to school in darkness more often.

With the DST change in 2007, many businesses and institutions will have to reprogram time clocks, security systems, timed safes, traffic lights, computers, and other devices that rely on built-in clocks.

In the United States, NIST uses atomic clocks that are accurate to within 1 second every 60 million years to set the official time. To handle the DST extension, “we can just change a couple lines in a computer program,” O’Brian says. “It’s a trivial thing. It would take 2 seconds to change that.”

Your computer probably already automatically adjusts for DST. But when the dates for DST change in 2007, you may have to download new software for your computer’s clock or remember to make the change manually.

Some people even question the idea of having daylight saving time at all. Is it worth going through the hassle of adjusting clocks twice a year? And some people have a tough time adjusting their sleeping habits when the time changes.

In 2007, at least in the United States, we’ll be at the start of a new experiment to see if daylight saving time does really make a difference and can help us save energy.

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An extensive series of tests has shown for the first time that these spiders don’t just eat the blood of vertebrates. They like it more than other types of food.

This small jumping spider prefers to stalk and pounce on blood-engorged mosquitoes.

Robert Jackson, University of Canterbury, New Zealand

There are at least 5,000 species of jumping spiders. Unlike many of their relatives, these spiders don’t build webs. Instead, they hunt the way cats do. They stalk midges, ants, spiders, and other prey, creeping to within centimeters of a victim. Then, in a tiny fraction of a second (0.04 second), they pounce.

One East African species of jumping spider (called Evarcha culicivora) doesn’t have the mouthparts to get through vertebrate skin to suck blood. Instead, it preys on female mosquitoes that have recently taken blood from animals. The spider eats the blood-filled insects.

Robert Jackson of the University of Canterbury in Christchurch, New Zealand, was one of the scientists who discovered and named E. culicivora 2 years ago. He noticed lots of these spiders living in and near houses in Kenya. To find out why, he launched a series of experiments.

First, Jackson and his coworkers presented the spiders with different types of prey. The spiders were quick to attack mosquitoes. This showed that the eight-legged creatures find mosquitoes to be yummy.

To find out whether E. culicivora prefer mosquitoes to other food, the researchers put spiders in clear boxes. From each of the four sides of the box, the animals could enter tunnels that led to dead-ends. The scientists placed prey outside each tunnel. They put one type of prey at two of the tunnels and a different type at the other two. The prey were dead, but they were mounted in lifelike poses.

Experiments with 1,432 spiders showed that more than 80 percent of the spiders chose tunnels leading to mosquitoes that had eaten blood. The rest chose to approach other species of prey.

In other tests, about 75 percent of spiders chose to approach female mosquitoes that had eaten blood rather than males (which don’t eat blood). They also chose female blood-eaters over the same kind of mosquitoes forced to feed on sugar instead.

Finally, the scientists pumped the odors of various prey into the arms of a Y-shaped test chamber. They found that spiders moved toward arms holding the scent of female blood-fed mosquitoes over other scents.

Even spiders that were raised in the lab and had never tasted blood were drawn to the sight and smell of blood-fed mosquitoes. This suggests that the taste for blood is something that this kind of jumping spider is born with.

The studies also mean that when a mosquito in East Africa bites you, your blood might eventually end up in the belly of a hungry jumping spider.—E. Sohn

Going Deeper:

Milius, Susan. 2005. Proxy vampire: Spider eats blood by catching mosquitoes. Science News 168(Oct. 15):246. Available at http://www.sciencenews.org/articles/20051015/fob8.asp .

You can learn more about Robert Jackson’s research on spiders at www.biol.canterbury.ac.nz/people/jacksonr/jacksonr_res.shtml (University of Canterbury).

The top three finishers in the 2005 Grand Challenge race for driverless vehicles (from left to right): Stanford University’s 2004 Volkswagen Touareg sports utility vehicle (nicknamed Stanley) and Carnegie Mellon University’s pair of Humvees, Highlander an

Carnegie Mellon University

Last year, 15 teams made it to the finals of the first Grand Challenge, a 142-mile (228-kilometer) road race across the desert (see “Robots on a Rocky Road“).

Any type of vehicle could enter the contest, but there was one big twist. Drivers were not allowed. Neither were passengers nor remote controls. Vehicles had to drive themselves over rugged terrain and around obstacles, with no help from people. None of the entries made it.

After watching vehicle after vehicle stall, crash, or burn, competitors refined their strategies and learned their lessons. This year, five out of the 23 finalists completed the 130-mile (210-kilometer) course through the Mojave Desert along the California-Nevada border.

About to cross the finish line, the driverless vehicle dubbed Stanley traversed more than 200 kilometers of rough terrain without human assistance.

D. Orenstein/Stanford

The winner of the $2 million prize was a blue 2004 Volkswagen Touareg sports utility vehicle, nicknamed Stanley. Customized by researchers at Stanford University with help from industry partners such as Volkswagen, Stanley easily beat a 10-hour time limit on the race. It breezed past the finish line in just under 6 hours, 54 minutes, and its average speed was slightly more than 30 kilometers per hour (19 miles per hour). At times, it topped 60 kilometers per hour (37 miles per hour).

Two vehicles developed by Carnegie Mellon University, Highlander and Sandstorm, came second and third. An earlier version of Sandstorm had competed in the first race and had traveled farther than any other entry.

Race veteran Sandstorm finished third in this year’s Grand Challenge.

Carnegie Mellon University

A U.S. government agency called the Defense Advanced Research Projects Agency (DARPA) created and sponsored the Grand Challenge. Given a boost by DARPA’s race, robotic vehicle technology is coming closer to fulfilling a government requirement that one-third of future army vehicles be driverless. The military would like to find better ways to transport goods during wartime without endangering soldiers.

This year’s resounding success was a result of recent advances in sensors and computer software, experts say. Stanley had five laser-beam sensors on its roof. It also had a specialized system for avoiding obstacles that was trained on data collected as human drivers navigated the car over a variety of terrain.

Soldiers aren’t the only ones who stand to benefit from the new technology. Someday, all cars and trucks might incorporate similar strategies to make our own road adventures safer and easier.—E. Sohn

Going Deeper:

Weiss, Peter. 2005. Road warriors: Robotic vehicles triumph over desert obstacles. Science News 168(Oct. 15):244. Available at http://www.sciencenews.org/articles/20051015/fob3.asp .

Sohn, Emily. 2004. Robots on a rocky road. Science News for Kids (April 21). Available at http://www.sciencenewsforkids.org/articles/20040421/Feature1.asp .

You can learn more about the DARPA Grand Challenge at www.darpa.mil/grandchallenge/ or www.grandchallenge.org/ (U.S. Defense Advanced Research Projects Agency).

The Stanford University team has a Web site at www.stanfordracing.com/ (Stanford University).

The two Carnegie Mellon University teams have a Web site at www.redteamracing.org/ (Carnegie Mellon University).

Since then, you’ve grown into a complicated organism with many trillions of cells grouped into specialized tissues and organs. The cells in your brain do the thinking. The cells in your heart pump blood. The cells in your tongue let you taste food. And so on.

In recent years, scientists have made an amazing discovery. Even though most cells have specific jobs, some primitive cells—called stem cells—exist in everyone’s body. Stem cells are unspecialized cells that can develop into nearly any type of body cell.

These images show human embryonic stem cell colonies, as grown in 1998 by researchers at the University of Wisconsin–Madison, in different stages of development.

© Science

Embryos—babies in the earliest stages of growth before they are born—have stem cells. Certain tissues in adults also contain stem cells, although the range of cells into which they can develop is limited.

In 1998, scientists at the University of Wisconsin–Madison figured out how to collect human embryonic stem cells and make them grow. Since then, researchers have learned to mix stem cells with combinations of proteins called growth factors to make the cells grow into different types of cells. Now, the search is on for ways to use stem cells to treat injuries and cure diseases.

For example, stem cells could be extracted, turned into new bone cells, and then injected into weak or broken bones. Or, they could become nerve cells that could heal spinal cord injuries, skin cells that could replace badly burnt skin, or brain cells that could help people who have suffered brain damage. The possibilities are endless.

“At this point, the ability to create all the different cells in the body has been pretty much proven to be real,” says Gary Friedman. He’s director of the Center for Regenerative Medicine in Morristown, N.J. “All the focus now is on getting new cells to behave the way we want them to and to go where we want them to go.”

Living better

Treating heart disease is one promising area of research. In dishes in the laboratory, scientists have already turned stem cells into heart cells, which gather into a group and throb in synch with one another, just like cells do in your heart.

At the University of Texas Health Science Center in Houston, researchers are now taking stem cells from a patient’s own body and injecting them into the heart to rebuild heart tissue and combat heart disease.

Human embryonic stem cells can turn into a variety of different cell types, including (A) gut, (B) neural cells, (C) bone marrow cells, (D) cartilage, (E) muscle, and (F) kidney cells.

© Science

Elsewhere, scientists are working to battle spinal cord injuries, diabetes, cancer, and more. But stem cells can’t cure all our ills. Some health problems are proving harder to treat this way than others.

Hearts, nerves, and livers are simple, Friedman says. Kidneys and lungs, on the other hand, are organs are tougher to repair. In kidneys, for example, stem cells have to not only specialize but also move into appropriate positions.

The goal of stem cell research is to help people live better, Friedman says.

“If kids are looking at their grandparents, maybe they see somebody who can’t walk well or somebody who is partly paralyzed because of a stroke,” he says.

“If you could take an older person and give that person cells to regenerate heart muscle or part of the brain that died during a stroke, or inject cells into joints to take away arthritis, all of a sudden you’re going to have a pretty vibrant person there,” Friedman says.

“This will help society,” he says. “People will be more functional instead of being in a weakened state and having to be cared for.”

More than science

As promising as the research may seem, discussions about stem cells often involve more than just science. Ethics is also involved, along with politics and religion, especially when it comes to stem cells taken from embryos.

So far, embryonic stem cells appear to be more useful than stem cells that come from adults. Because an embryo’s cells are still dividing and specializing anyway, its stem cells can still become almost anything. By the time we grow up, however, our stem cells have a more limited ability to diversify.

To repair heart muscle in a mouse, researchers inject adult stem cells into the muscle of the damaged wall of a mouse heart.

National Institutes of Health

The problem with embryonic stem cells, for some people, is that they originally come from destroyed embryos. Many scientists argue that stem cells are our best hope for curing a huge number of diseases. They also argue that fertility clinics end up with a surplus of embryos that are never born anyway.

Nevertheless, critics think its wrong to use cells from dead embryos. It’s a very complicated issue that involves basic beliefs about when life begins, and these are the types of beliefs about which people tend to feel passionate.

Some recent research may help put an end to the debate, Friedman says.

A new technique called “somatic cell nuclear transfer” has given scientists the ability to create embryonic-like stem cells out of a person’s own cells. This strategy is especially appealing to doctors, because it’s always better to use a person’s own cells for transplants and injections. Our bodies often reject cells that come from someone else, even if that someone else is an unborn embryo.

Scientists have also found embryonic-like stem cells in umbilical cord blood. About 100 million babies are born each year, and every one of them has an umbilical cord that connects it to its mother. If umbilical cords prove to be a reliable source, the supply of stem cells could be enormous and controversy-free.

All this may sound a bit confusing, but it’s worth learning more. Stem cells are big news in medicine right now. “I don’t think a day goes by when there aren’t articles or something on the Web about it,” Friedman says.

As you get older, you’re bound to hear more and more about stem cells.

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