Buy a better earth: Science World goes shopping for the environment

Science World, April 5, 2004 by Libby Tucker

How much cash did you burn through at the mall last weekend? Each year, young people spend $170 billion on food, clothing, and entertainment. But all that stuff costs more than you think.

"A lot of consumers don't realize the hidden costs behind what they buy," says Lisa Mastny of the Worldwatch Institute. "Anything from a CD or DVD to clothes and cars has a story beyond what it's used for. There's a connection between the product and its impact on the environment."

Take our shopper's quiz, (right), to find out how well you know what your money buys. Then read on to learn how to make purchases that won't add up to an expensive shopping trip for Planet Earth.

EXPENSIVE ELECTRONICS

In 1999, more than 10 percent of America's electricity was used to power gadgets like computers, alarm clocks, and cell-phone chargers (see chart, below). That's enough energy to power Ecuador for at least 10 years! The kicker: Half of all the energy an electronic device uses is sucked up in standby mode, or when it's not in use but still plugged in.

That means there's no need to give up CDs or American Idol. "Using [electronics] less is not going to make as much of a difference as unplugging them," says Karen Herter, an energy researcher at Lawrence Berkeley National Laboratories. The best thing you can do, she says, is buy Environmental Protection Agency-rated "Energy Star" electronics that are more efficient in standby mode.

YO-YO SOLUTION

A stereo gets its energy from a cord plugged into the wall. But what powers all those gadgets in your backpack or purse? Most small electronics like cell phones, PDAs, and portable CD players run on batteries. The hidden cost: Many of those batteries recharge with electricity from an outlet. That's why engineers Chris Aimone and Tomek Bartczak designed the reGen MP3 player. It uses energy from a spinning yo-yo to crank out music.

Here's how it works: Fresh out of your hand, a dropped yo-yo has potential energy (stored energy). As the yo-yo falls, some of that potential energy turns into rotational kinetic energy (energy of spinning motion), which whirls the yo-yo. As the disc nears the bottom of the string, it has converted all its potential energy into kinetic energy. "You can see when it has more kinetic energy because it spins faster," says Gordon Jones, a physicist at Hamilton College in Clinton, New York.

But the toy gets most of its power from your yo-yoing arm. "You can throw the yo-yo down as hard as you throw a ball," says Aimone. The energy from your arm muscles transfers to the yo-yo and makes it spin even faster.

A professional yo-yoer can keep the disc spinning at the bottom of the string for minutes. At this stage, the pros use the kinetic energy of the spinning yo-yo, to do tricks like "walk the dog." But in the reGen yo-yo, that energy is used to charge the MP3 player's batteries. "It's like a yo-yo trick, but you pull that energy out to do something useful," says Jones.

Only 10 to 12 swings of the yo-yo is good for up to an hour of listening. Now that's music to your ears!

GRAPH IT!

Using the chart (left), create a bar graph to compare the five most energy-hungry devices. How can you reduce your energy consumption?

PAPER DOESN'T PAY

Next tinge you pass a note to a friend or clean a spill with paper towels, consider this: You're using part of a tree. The paper for these products comes from wood that's shredded, pulverized, and mixed with thousands of gallons of water and chemicals to create wood pulp (water-and-wood mixture). The process takes precious energy and water, not to mention valuable trees.

Eighty percent of the world's original forests have already been bulldozed. That means fewer habitats for wildlife, less oxygen-producing vegetation, and more erosion (washing away) of soil no longer anchored by tree roots.

It also takes more water to make a ton of paper than it does to make any other industrial product in the U.S. And paper mills are the nation's second-largest energy consumer.

A smart shopper's job? Consider more than just the color of a notebook cover or the paper towel's pattern. Flip the package over and look for a label that says "this product contains post-consumer waste (recycled materials)." Paper made from recycled materials uses less water and energy and doesn't require more trees.

But beware: There's no standard label for eco-friendly paper products. "A label that says 'Earth-friendly' could be [made from] anything," says Mastny. "The clearer the label, the better."

SPENDER BENDER

One day futuristic electronic paper, or e-paper, could cram all of your heavy textbooks into one lightweight notebook. Flexible like a magazine, e-paper stores loads of information in its computer chips and rolls up like a pen-sized scroll to fit snugly in your pocket. "The technology allows people to carry large amounts of information with them in an easy-to-read format," says Darren Bischoff of E-Ink, one company developing the technology.

The e-paper is made of plastic coated with tiny microcapsules, or beads. The beads are filled with a clear liquid that holds thousands of tiny black and white particles. The black particles have a negative electrical charge (when atoms or molecules in a material lose or gain electrons, or particles that orbit an atom's center), and the white particles are positively charged.