You've probably seen a light powered by a lemon or a clock hooked up to a potato before, but a group in London recently built a similar device using a much smaller, less popular piece of produce. To promote The Big Bang UK Young Scientists & Engineers Fair, a team of designers built the world's first Brussels sprout-powered battery and hooked it up to a set of Christmas tree lights.
Every year, the fair's organizers try to find new ways to get kids interested in science and technology. So after a survey found that most children in the UK would like to take Brussels sprouts off of the traditional Christmas menu, the group came up with the idea for the vegetable-powered tree and enlisted the help of the Designworks design group to make it happen.
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The battery itself is comprised of five power cells, which are modeled after the appearance of natural Brussels sprouts stalks. Each cell is surrounded by 200 sprouts for a grand total of 1,000 Brussels sprouts in the whole battery. The sprouts are each mounted onto copper and zinc electrodes, which triggers a chemical reaction between the electrolytes in each sprout and produces a small current. A capacitor collects and stores the energy from all the sprouts before releasing it to the tree's lights. A digital display on top of the battery also shows how much voltage it is producing in real-time.
Even with a huge amount of Brussels sprouts though, the battery can only produce about 62 volts and 10mA of current, which is low but still enough to power the tree's 100 high-efficiency LEDs. According to the organizers, the sprouts should be able to light up the tree for several weeks, though they will need to be exchanged for fresh ones at some point to keep the tree lit over the holidays.
It may not be the most practical source of energy in the world, but most kids would probably prefer to see Brussels sprouts lighting a Christmas tree instead of landing on their plates.
Be sure to check out the video below to see the moment of truth when a group of school children switches on the sprout-powered Christmas tree.