B.C. teenager’s ‘hollow flashlight’ takes her to the Google Science Fair

There are some exceptional young scientists going to the Google Science Fair this year, and among the finalists is 15-year-old Ann Makosinski, from Victoria, B.C., who invented a hollow flashlight that can generate light right from the palm of your hand.

This very cool new flashlight uses a principle called the thermoelectric effect — using temperature difference to make electricity or vice versa — which has been used to make heat pumps or thermoelectric coolers.

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If you hooked up one of the 'Peltier tiles' in this flashlight to a battery, one side of the tile would heat up and the other side would get cold (and it's always the same sides). This would eventually reach a point where it stopped, maintaining the same temperature difference between the two sides. If you cooled the 'hot' side of the tile or heated the 'cold' side of it (or both), the tile would draw more current from the battery to push more heat from the 'cold' side to the 'hot' side, to try to keep the same temperature difference.

What Makosinski did was to leave out the power supply, and instead hook up a set of wires and a power transformer, and run the whole thing in reverse. She put the 'cool' side of these tiles against the outer shell of the flashlight handle, and the 'hot' side of the tiles against a hollow aluminum tube inside the handle. As the heat from the hand holding the flashlight warms the 'cool' side of the tile, the tile moves that heat to the other side, generating an electric current. When the heat reaches the other side, the room-temperature aluminum pipe draws the heat away, and this sets up a continuous current that runs through the transformer and makes the LEDs light up. As long as there's a temperature difference between the two sides of the tile, the electricity will flow and the greater the temperature difference, the brighter the flashlight will be.

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This flashlight is just one of the latest ideas in the field of 'energy harvesting' — generating electricity from the things we do all the time. Every step you take on a sidewalk could be turned into electricity if that sidewalk was made from a piezoelectric material (generating electricity through compressing crystals). Every swing of your arms as you walk could generate electricity if your jacket was made of a material (or was laced with a material) that turned kinetic energy into electricity. Even the heat from your body is a wasted energy source as it just radiates into the air.

It's unlikely that we'd end up replacing all the other power generation sources through this, but we could reduce our burden on those other sources, and it wouldn't take up any more effort on our part, other than what we normally do on a day-to-day basis.

Makosinski will have to wait until September 23rd to find out if she's this year's Google Science Fair winner, but it's worth the wait. Top prize is a $50,000 scholarship, a 10-day National Geographic Expedition to the Galapagos Islands, plus an amazing chance to work with either Google, LEGO or CERN.

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