You thought lemon only goes with food and beer? You were wrong. It can even run a clock, effortlessly. The theory behind the lemon clock is based on the principle of electrolysis. The combination of zinc and copper, (basically the plug under the lemon), when reacts with any acidic medium (in this case, the lemon) causes oxidation, ultimately resulting in electricity. The device below allows you to keep the clock active for over a week using just 1 lemon. Good old chemistry, makes me remember my school days.