text: project lemon light nutural batteries? i need to know how this work i dont under stand this my mom said she dont know too. this is for school i am in 4grad.please help me apples or potatoes could also work, but a lemon works better because it is more acidic. the acid in a lemon is what makes it taste sour, by the way.  the idea is that if you stuck two objects made of different kinds of metal (like a penny and a zinc-coated nail) into different ends of the lemon, you have something that acts like a battery, with a negative and postive pole. the lemon gets its electricity from the chemical reactions between the acid and the metal, which creates a small negative charge on one end, and a small positive charge on the other.   if you do this, you should never try to eat the lemon or drink its juice because the chemicals created by the reaction between the juice and the metal are poisonous.   all batteries are basically made in the same way. most batteries don't have a peel, but they usually have something solid which holds in an acid.    the acid in a car battery is much stronger than lemon juice, and you do not want it anywhere near your skin or your eyes! if any kind of battery is leaking, you  want to throw it away very carefully.   if you throw away batteries in the regular trash, they often end up buried in a landfill, leaking poison into the earth. we hope these chemicals don't end up in your drinking water.   that's why it's not only cheaper to use rechargeable batteries, but also better for the earth and the people who live there. rechargeable batteries are even more poisonous than other batteries, but since you use them much longer, you don't throw away as many batteries.  now, the lemon battery isn't a very good battery. you could not light a light bulb with it because the charge is very weak. i saw one that was hooked up to a clock for about a year. the clock was running the whole time, but the time was wrong because the lemon battery was weaker than the kind you usually buy in the store.   the websites below may help you or your mom understand the lemon battery better.