Electric Circuit Experiments: Lemon Battery

Video Transcript

"Let me show you how to make a battery with some lemons and a potato here. This is one of the simplest experiments you can do with electricity and food. I'm just going to take a knife and I'm going to cut two slits right here on either end if my lemon here. And lemons probably make the best batteries, because they have some acid in them, which helps conduct electricity a lot. It's why we have acid in batteries. Now, I'm going to take my battery here, which is just like a nine volt battery, and I'm going to take the positive ends and I'm going to connect it up to a copper penny. And I'm going to take that penny and I'm going to put it into one of these little slits that I just cut. So, the penny is touching the inside of the lemon and the alligator clip is connected up to the penny. It travels over to the positive side of my batteries and I've got a connection. Now, I'm going to take a silver coin -- these are usually made with some zinc in them -- a nickel, a dime, a quarter, it doesn't matter. But, you've got to use two different metals to get the best results. And I'm going to put the nickel on the other side. And once again, I'm going to make it so that it touches the inside of the lemon, carries any electricity in there up through the lead. And then we've got some conduction happening. And actually what I'm doing, my batteries right now are here. I'm just showing you this is a conductor. So, let's check it out with the multi-meter. We're just checking to see if this is a good electrolyte. So, always take the black lead of my multi-meter and put it toward the negative side and the positive side. I'm going to connect up the ground. And, indeed, it's conducting across my battery signal of 2.5 volts. The amazing part, though, if I remove these, the negative side becomes the silver coin, my zinc coin, and the positive side is now the copper coin. And we are now registering, albeit a kind of weak voltage, we've got a battery that's producing about .05 volts right now. And if I squeeze it and I break it up and I get more juice going, then my voltage is going to go up. It's going to register more voltage. So, right now, it's showing about .22 right now, .24, .25. Every once in a while you get a really good lemon. If you smash them up, you can get about a maximum of .1, .2, .3 volts out of it. But you can see there's definitely electricity here. If I let go, I don't measure any electricity. If I connect it up, I get electricity. And this is what runs the potato clock, or lemon clock or an apple clock or any kind of device that's powered by fruit or vegetables."