Electricity's Spark of Life

Electricity's Spark of Life

Lots of kids get scared when their bedroom lights go out at night. When an entire city goes dark, many more people start to worry.
Government and utility officials are still scrambling to explain a blackout that hit much of the northeastern United States in late summer. From Detroit to New York, lights went out. Refrigerators, traffic signals, elevators, and subway trains stopped working. Computers went dead.

Without electricity, people had trouble getting to work, shopping for groceries, and communicating with each other. Normal life pretty much shut down for a few days.
Electricity also plays a crucial role within the human body. A lightning bolt or shock can disrupt or shut down that flow, causing disability or death.
"Electricity is life," says David Rhees, executive director of the Bakken Library and Museum in Minneapolis. The Bakken museum is dedicated entirely to the history and applications of electricity and magnetism in biology and medicine.
The museum has a lot to keep up with. As scientists learn more about the electrical signals that whiz through our bodies and the electrical pulses that tell our hearts to beat, they are finding new ways to use electricity to save lives.
Research on the nervous systems of animals and people are helping scientists design machines that help diagnose and treat brain conditions and other problems. New drugs are being developed to regulate the body's electrical pulses when things go wrong in response to injury or disease.
Electricity everywhere
Electricity is everywhere, thanks to the unique structure of the universe. Matter, which is basically everything you see and touch, is made up of tiny units called atoms. Atoms themselves are made up of even tinier parts called protons and neutrons, which form the atom's core, and electrons, which move around outside the core.
Protons have a positive electrical charge, and electrons have a negative electrical charge. Normally, an atom has an equal number of electrons and protons. The positive and negative charges cancel each other out, so the atom is neutral.
When an atom gains an extra electron, it becomes negatively charged. When an atom loses an electron, it becomes positively charged. When the conditions are right, such charge imbalances can generate a current of electrons. This flow of electrons (or electrically charged particles) is what we call electricity.
The first person to discover that electricity plays a role in animals was Luigi Galvani, who lived in Italy in the late 18th century. He found that electricity can cause a dissected frog's leg to twitch, showing a connection between electrical currents traveling along an animal's nerve and the action of muscles.
Quick signals
All animals that move have electricity in their bodies, says Rodolfo Llinas, a neuroscientist at New York University's School of Medicine. Everything we see, hear, and touch gets translated into electrical signals that travel between the brain and the body via special nerve cells called neurons.
Electricity is the only thing that's fast enough to carry the messages that make us who we are, Llinas says. "Our thoughts, our ability to move, see, dream, all of that is fundamentally driven and organized by electrical pulses," he says. "It's almost like what happens in a computer but far more beautiful and complicated."
By attaching wires to the outside of the body, doctors can monitor the electrical activity inside. One special machine records the heart's electrical activity to produce an electrocardiogram (EKG)—strings of squiggles that show what the heart is doing. Another machine produces a pattern of squiggles (called an EEG) that represents the electrical activity of neurons in the brain.

One of the newest technologies, called MEG, goes even further. It actually produces maps of magnetic fields caused by electrical activity in the brain, instead of just squiggles.
Recent observations of patterns of nerve-cell action have given scientists a much better view of how electricity works in the body, Llinas says. "The difference between now and 20 years ago is not even astronomical," he says. "It's galactic."
Now, researchers are looking for new ways to use electricity to help people with spinal injuries or disorders of the nervous system, such as Parkinson's disease, Alzheimer's disease, or epilepsy.
People with Parkinson's disease, for example, often end up having tremors and being unable to move. One type of treatment involves drugs that change the way nerve cells communicate with each other. As part of another new treatment, doctors put tiny wires on the head that send electrical impulses into the patient's brain. "As soon as you put that in," Llinas says, "the person can move again."
Philip Kennedy at Emory University in Atlanta has even invented a kind of "thought control" to help severely paralyzed people communicate with the outside world. His invention, called a neurotrophic electrode, is a hollow glass cone filled with wires and chemicals. With an implanted electrode, a patient who can't move at all can still control the movement of a cursor across a computer screen.
Looking to the past
One way to help keep the medical field speeding into the future might be to cultivate an appreciation for the past. At least, that's what the folks at the Bakken museum think.

When I recently visited the museum, Rhees and Kathleen Klehr, the museum's public relations manager, took me down to a huge padlocked room in the basement called "The Vault." Row upon row of shelves were crammed with rare, old books about electricity, early versions of pacemakers and hearing aids, and all sorts of weird devices. One was a shoe-store X-ray machine, powered by electricity, that showed you whether your foot fit comfortably into a new shoe.
Upstairs, the exhibits included a tank of electric fish and Hopi dolls dedicated to the spirit of lightning.
There's also a whole room dedicated to a monster made famous in a book titled Frankenstein. Made from assorted human parts, the monster was brought to life by an electrical spark. When Mary Shelley wrote Frankenstein in 1818, electricity was still a relatively new idea, and people were fascinated by the possibilities of what they might be able to do with it.
Even today, the Frankenstein room, with its scary multimedia presentation, remains one of the Bakken's most popular exhibits, Klehr told me. "It's been centuries," she says, "and everyone is still excited about Frankenstein."
That's something you might keep in mind the next time a blackout strikes. Without electricity, those monsters under your bed might have a lot less power over you!

Einstein's Skateboard

Einstein's Skateboard

Albert Einstein never rode a skateboard. Last month, however, skateboarders caught big air on a halfpipe in honor of the famous physicist.
In a field house on the campus of the University of Maryland in College Park, near Washington, D.C., a handful of skaters and a BMX biker took turns pulling tricks on the pipe. Off to the side, five middle-school students watched intently. With video cameras bearing down on them and a deadline approaching, the students worked frantically to solve the team's first problem of the day.

Our challenge," said David Westrich, 14, of Cape Girardeau, Mo., "is to find the points along the halfpipe where skaters experience the most and least gravitational force."
"Skateboard Physics" was one of six activities that eight teams tackled as part of this year's Discovery Channel Young Scientist Challenge (DCYSC). Every year, the competition brings the nation's top 40 middle-school science-fair winners to Washington, D.C., to battle for thousands of dollars in scholarship money, dream science trips, video cameras, and other prizes.
Finalists are judged individually on their ability to work as part of a team and to solve problems in clever ways. Students also need to be good at explaining their ideas. Swarms of video cameras follow contestants everywhere they go. When the week is over, the Discovery Channel produces a TV special about the event.
Star of the show
This year at DCYSC, although the students received plenty of attention, Albert Einstein was the star of the show.
Nearly 100 years ago, in one "miraculous year," Einstein wrote three research articles that changed the face of physics forever. In one article, he showed how light could be viewed as waves of radiation or as a beam made up of particles—little bundles of energy. In another, he introduced relativity theory and later showed that energy can be converted into matter and matter into energy. Finally, he explained how tiny particles get bounced around in a liquid.
To mark the 100th anniversary of Einstein's amazing work in 1905, the year 2005 has been designated the "World Year of Physics." In 2000, Time magazine had named Einstein "Person of the Century."

So, it's not surprising that Einstein became the theme of this year's DCYSC competition. "Einstein is the man," said challenge designer Steve "Judge Jake" Jacobs. "He's a legend."
Einstein's scientific achievements involved thinking in new ways. He spent his time doing "thought experiments" rather than mixing things together in a lab.
"Einstein was able to focus his thinking so perfectly," Judge Jake said. "Here, the kids have to focus their thinking to achieve their goals."
Judge Jake's hope was that finalists would go home with a sense of appreciation for how brilliant Einstein really had been and a drive to be just as successful. "I hope that, just for a moment, they'll think the way Einstein thought," he said.
Radar guns
Four out of six challenges this year had direct connections to physics and Einstein.
In the "Skateboard Challenge," teams had to figure out that the gravitational force was greatest as the skaters accelerated downhill and that it was smallest when the skaters reached the top, just before starting down again. They used a computer program and data from a high-definition video camera and a device called an accelerometer to test their predictions.
One of the other physics-related activities was called "Radar Gun Luge." In it, students checked out the notion that the speed of an object, as measured by a moving observer, depends on the observer's speed.
Finalists used radar guns to measure the speed of two luge carts. One cart held a wild-haired Einstein doll. The other carried a remote-controlled radar gun.

Team members had to drag the carts to the top of two steep tracks, then release the carts at the same time. Altogether, they had 90 minutes to confirm that the doll's measured speed was twice as fast when measured from the other cart moving toward it as when it was measured by an observer standing at the side.
If this sounds confusing to you, you're not alone. More than halfway through the activity, the red team was looking visibly shaken. "All of our data is useless," said Nicholas Ekladyous, 14, from Imlay City, Mich., with a hint of panic in his voice.
"We have no data," answered his teammate Rebecca Chan, 13, from Encinitas, Calif.

Discussion about what to do next rapidly turned sour. With just 10 minutes left, Nick was trying to persuade his teammates that they should abandon their original strategy and make a new plan. "Nick," Rebecca said, "it's going to take you longer to talk us out of this than for us to just do it."
After that temporary breakdown, it was on to the next challenge.

A New Basketball Gets Slick

A New Basketball Gets Slick

Basketball players need more than strength, speed, and skills to be on top of their game. Technology, too, can make the difference between a slam dunk and a stolen ball.
Now, technology and basketball seem to have collided, and some players are calling foul. At the center of the debate is a new type of ball introduced over the summer by the National Basketball Association. The NBA season began last week.

Basketballs used in NBA games have long had a leather cover. The new balls, however, are covered with a special kind of plastic. Spalding, the company that makes the new balls, insists that thorough tests during development showed that the synthetic covering performs better than leather does.
Experiments by scientists in Texas, however, seem to show otherwise. The researchers suggest that the plastic balls are less bouncy, more likely to bounce off course, and more slippery when moistened with sweat. These early experimental results suggest that this change in ball design could have a big effect on the quality of game play.
To compare friction, or the ball's ability to stick to surfaces (such as hands), the scientists took measurements as they slid both old and new balls against sheets of silicon. Silicon is similar to the palms of our hands in its degree of stickiness.
When dry, the old leather balls slid more easily than did the new plastic balls. When moistened with just one drop of a sweat-like liquid, however, the plastic balls became a lot more slippery than when they were dry.
Leather balls actually became stickier with sweat. And they absorbed moisture about eight times more quickly than the plastic balls did.
"When the balls are dry, the synthetic ball is easier to grip, and when they're wet, the leather one is much easier to grip," says physicist James L. Horwitz of the University of Texas-Arlington.
To keep professional players from dropping the ball, it may be necessary to change and clean balls throughout a game.
Some scientists are urging the NBA to reconsider the switch until scientists finish further testing.
John J. Fontanella, a former college basketball player and now a physicist at the United States Naval Academy in Annapolis, Md., belongs to that group. "The NBA," he says, "should stick with the leather basketball for another year."

Powering Ball Lightning

Powering Ball Lightning

Ball lightning is one of the strangest objects you might never see. The rare, basketball-sized fireballs occasionally form in nature after lightning strikes soil. They can float or bounce and last for several minutes before disappearing.
In recent years, scientists have learned something about the science behind ball lightning. But questions remain. A new study helps illuminate the picture.

Researchers at Tel Aviv University in Israel began the study after making ball lightning by mistake in their lab. Vladimir Dikhtyar and Eli Jerby had just invented a new type of drill that was made partly from pieces of microwave ovens.
The tip of the drill concentrates microwave radiation into a spot that measures just 2 millimeters wide. Such concentrated radiation allows the drill to pierce many materials.
About 10 years ago, Dikhtyar and Jerby were testing their new device when a glowing blob suddenly blew out of the material they were drilling. The blob eventually reentered the drill, causing a lot of damage.
Hoping to find out what had ruined their fancy tool, the engineers experimented until they could reliably make fireballs on purpose. The trick, they found, was to drill into glass.
They found a way to cage the glowing blobs for up to several minutes. To make the trap, they used a tissue-box-sized container with glass walls. They kept the glowing orbs alive by zapping them with extra microwaves.
The lab-made blobs were different from ball lightning that occurs in nature. For one thing, the artificial balls were much smaller—just a few centimeters across, instead of basketball-sized or bigger. They formed in a different way too. And if left alone, the manmade blobs vanished within 30 milliseconds. (There are 1,000 milliseconds in 1 second).
Still, the scientists thought their blobs were realistic enough to help test one of the leading theories about what causes ball lightning in nature.
In 2000, researchers from the University of Canterbury in Christchurch, New Zealand, proposed that ball lightning forms when lightning strikes soil. Under the right conditions, the strike creates a charged gas that glows and contains dust that is full of microscopic particles. Chemical reactions within the dust then create energy that keeps the gas glowing, the scientists suspected.
Using an intense X-ray beam, Dikhtyar and Jerby found evidence to support that theory. Their tests showed tiny particles within the artificial blobs. These particles were similar in size to the particles that may exist in natural ball lightning

A new look at Saturn's rings

A new look at Saturn's rings

Many students know that to figure out the age of a tree, you count the number of rings that make up its trunk, one ring for each year. But what if you wanted to know the age of the rings that surround the planet Saturn?
It's a tricky question that scientists have tried to answer for decades. In the late 1970s, the National Aeronautics and Space Administration, or NASA, sent a pair of spacecraft called Voyager 1 and Voyager 2 into outer space. Part of their mission was to fly past Saturn while taking pictures of and collecting data about the planet, then send all this information back to Earth.
Based on the data collected on those missions, scientists first estimated that the rings surrounding Saturn were only 100 million years old. Even though that sounds very old, 100 million years is actually quite young when compared with the solar system, which is 4.6 billion years old.
Looking at the physical characteristics of the particles that make up the rings is partly what helped astronomers determine the age. They reasoned that because the rings appear shiny and reflective, the particles in them, and the rings themselves, were fairly young. The scientists thought that the particles were young because they had not been around long enough for their surfaces to become darkened and less reflective. Things like dust and craters left from collisions with small meteorites can get particles dirty.
But a team of researchers in Colorado thinks Saturn's rings might be much older, closer to the age of the solar system itself. These researchers used a combination of computer simulations, which mimic events, and data from the Cassini spacecraft, which is currently orbiting Saturn and collecting data.
In the computer simulation, the team estimated the gravitational pull, a force that pulls objects together, between each of the particles making up the rings. Big particles in the rings may pull smaller particles to themselves, where they stick and make one larger particle. In their simulations, the researchers found that the particles making up Saturn's rings stick together in clumps and are not uniformly distributed, as previously thought.
The formation of new, larger ring particles from older, smaller ones could erase any surface darkening from previous collisions with meteorites, the researchers reasoned. They suggest the particles may look younger than they really are because they constantly clump together, possibly burying the cratered, dusty surface of the older particles beneath the surface of the new clumped particles.
Because of these clumped particles, scientists may have also underestimated the mass of the rings. Previously, astronomers calculated the mass of the rings by measuring how much starlight their particles blocked. The thinking was that the amount of blocked starlight could tell the amount of material in the rings. The more starlight was blocked, the more mass was present in the rings, the scientists reasoned.
But the older calculation assumed the particles were fairly evenly spread out in the rings. These newer data suggest the particles in the rings are clumped together with large empty spaces between them. In that arrangement, more light passes through than if the same mass of particles was spread evenly, as previously thought. This new understanding suggests Saturn's rings contain much more mass than scientists first estimated.
Taken together, the findings raise new questions about the estimated age of Saturn's rings, says Mark Lewis, a computer scientist at Trinity University in San Antonio, Texas. But until astronomers know more about what material the ring particles are made of, and details about how they clump together, the age of Saturn's rings will remain an astronomical puzzle.

Galaxies on the go

Galaxies on the go

Scientists have a mystery of cosmic proportions on their hands. Recently astronomers noticed something strange. It seems that millions of stars are racing at high speeds toward a single spot in the sky.
Huge collections of stars, gas and dust are called galaxies. Some galaxies congregate into groups of hundreds or thousands, called galaxy clusters. These clusters can be observed by the X-rays they give off.
Scientists are excited about the racing clusters because the cause of their movement can't be explained by any known means.
The discovery came about when scientists studied a group of 700 racing clusters. These clusters were carefully mapped in the early 1990s using data collected by an orbiting telescope. The telescope recorded X-rays created by electrons located in the hot core of a galaxy cluster.
The researchers then looked at the same 700 clusters on a map of what’s called the cosmic microwave background, or CMB. The CMB is radiation, a form of energy, leftover from the Big Bang. Scientists believe that the Big Bang marks the beginning of the universe, billions of years ago. The CMB provides a picture of how the early universe looked soon after the Big Bang.
By comparing information from the CMB to the map of galaxy clusters, scientists could measure the movement of the clusters. This is possible because a cluster’s movement causes a change in how bright the CMB appears.
As a galaxy cluster moves across the sky, the electrons from its hot core interact with radiation from the CMB. This interaction creates a change in the radiation’s frequency, or how often an event occurs in a certain amount of time. Scientists can then measure the frequencies to detect movement.
As a galaxy cluster moves toward Earth, the radiation frequency goes up. As a cluster moves away from Earth, the frequency goes down. This shift in the frequencies creates an effect similar to the Doppler effect.
The Doppler effect is commonly used to measure the speed of moving objects, such as cars. Scientists can use this method to measure the speed and direction of moving galaxies by looking at changes in the radiation frequencies.
What the scientists found surprised them. Though the frequency shifts were small, the clusters were moving across the sky at a high speed — about 1,000 kilometers per second. Even more surprising, the clusters were all moving in the same direction toward a single point in the sky.
Researchers don’t know what’s pulling this matter across the sky, but they are calling the source “dark flow.”
Whatever it is, scientists say the source likely lies outside the visible universe. That means it can’t be detected by ordinary means, such as telescopes.
One thing is certain. Dark flow has shown that we don’t understand everything we see in the universe and that there are still discoveries to be made.

Earth from the inside out

Earth from the inside out

Scientists have long known this strange fact: It’s easier to look deep into space than into the center of Earth. Light can pass through most of space, so the light from distant stars can easily be seen with the naked eye. But Earth is opaque, which means that light cannot pass through it.
If light cannot pass through it, then we cannot see what’s on the inside of our planet. So if we can’t use light to see inside our own planet, what can we use?
Recently, some scientists have been trying to use neutrinos — tiny particles smaller than an atom that zip through space. Neutrinos come from the sun or other distant stars, and astronomers have studied them for years. Now, a team of geoscientists — “geo” means Earth — think a kind of neutrino may have something to say about the Earth, too.
Not all neutrinos come from outer space. Special neutrinos called geoneutrinos are generated from within the Earth. (Remember that “geo” means Earth.) Most of these local neutrinos come from either the crust or the mantle. The crust is Earth’s outermost shell, what we stand on, and the mantle is five to 25 miles below the crust. Certain elements within the Earth can send off geoneutrinos when undergoing a process called radioactive decay.
During radioactive decay, a material loses some of its energy by sending out particles and radiation. An element that goes through this process is said to be radioactive, and radioactive elements occur naturally in the Earth. Some radioactive elements produce geoneutrinos.
After they are produced, geoneutrinos pass straight through the solid Earth without being absorbed or bouncing around. If they’re not stopped, they go straight into outer space — and keep going, and going and going. Geoscientists hope to catch a few of these particles on their way out, but it’s not going to be easy.
There are two big problems: There aren’t that many geoneutrinos, and they’re hard to find. To catch these elusive particles, scientists have designed special geoneutrino detectors. These strange-looking scientific instruments are giant, metal spheres buried deep underground.
In an abandoned mine in Canada, for example, scientists are preparing a geoneutrino detector that is four stories tall and more than a mile underground. The detector will be filled with a special liquid that flashes when a geoneutrino passes through. The liquid “produces a lot of light, and it’s very transparent,” says Mark Chen, the director of the project. When it’s up and running, probably in 2010, the detector will find only about 50 geoneutrinos per year. Other detectors are being planned all over Earth — one of them is even supposed to sit on the bottom of the ocean!
The geoscientists who study geoneutrinos hope that the particles will help answer an old question about the Earth. The interior of the Earth is blistering hot, but where does the heat come from? They know that part of the heat — maybe as much as 60 percent — comes from radioactive decay, but researchers want to know for sure. By measuring geoneutrinos, scientists hope to figure out how radioactive decay helps heat Earth.