Living on Earth’s Cynthia Graber reports on a way to use electricity to put the brakes on at the ski slopes.
CURWOOD: Just ahead, browsing for a better bird book. First, this environmental Technology Note from Cynthia Graber.
GRABER: Those who enjoy the rush of skiing down the slopes but worry about uncontrollable speed, may soon be able to get a little help slowing down from electricity. Victor Petrenko, an engineer at the Dartmouth College Ice Research Lab, has developed brakes for skis and snowboards. He's placed two wires under the length of the ski or board. The main wires have branches off them, so the ski or snowboard is covered with a grid of positive and negative charges. These wires are connected to a small battery embedded in the ski and activated by a computer chip. The system works because ice has an unusual property. It forms the opposite charge of the surface it comes in contact with. So, when a wire has a negative charge, the ice forms a positive charge. When the wire is positive, the ice becomes negative. And, since opposite charges attract and stick together, friction increases and the board or ski slows down.
There's another way these wires help control speed. There are tiny ridges on the surface of ice. Applying electrical current melts these ridges, but as soon as contact is broken the ice freezes again. This melting and freezing adds additional friction to slow skis down. Victor Petrenko hopes to have electrically braking skis on the market by 2003. That's this week's Technology Note. I'm Cynthia Graber.
CURWOOD: And you're listening to Living on Earth.
[MUSIC: Trans Am, "Cologne", ENJOY THE NIGHT (Thrill Jockey - 1997)]
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