Learning to experiment and observing what happens is a core part of science. It is said that Thomas Edison tried hundreds of materials in the light bulb (even a strand of his own hair) before he found that tungsten filament lit up. Always supervise children when doing science experiments.
What you need:
– 2 lemons
– 3 copper wires
– 2 large paper clips
– 2 one-cent coins
– A digital clock
– Scissors
– Knife
What to do:
1.) First, attach one of the paperclips to a wire.
2.) Then attach a one cent coin to a second wire.
3.) Attach another one cent coin to one end of the third wire, and a paperclip to the other end.
4.) Squeeze and roll two lemons to loosen the pulp inside.
5.) Make two small cuts in the skins of both lemons an inch or so apart.
6.) Put the paper clip that is attached to the wire and the one cent coin into one of the cuts until you get to the juicy part of the lemon.
7.) Stick the one cent coin into a hole in the other lemon.
8.) Put the other paper clip into the second hole of the lemon with the one cent coin.
9.) Then put the last one cent coin into the last open hole.
10.) Connect the free ends of the wires to the terminals of the digital clock.
11.) Watch how the lemons make enough electricity to turn the clock on. If you’ve hooked everything up and the clock isn’t running, try switching the wires.
The science:
Here’s how this lemon battery works. There’s a chemical reaction between the steel in the paper clip and the lemon juice. There’s also a chemical reaction between the copper in the one cent coin and the lemon juice. These two chemical reactions push electrons through the wires.
Because the two metals are different, the electrons get pushed harder in one direction than the other. If the metals were the same, the push would be equal and no electrons would flow. The electrons flow in one direction around in a circle and then come back to the lemon battery. While they flow through the clock, they make it work. This flow is called electric current.
This is hard to understand. So, go through it slowly with kids and don’t expect them to grasp it at first but over time. Understanding the experiment and the outcome is great.
Now you can experiment:
1.) Do you think your lemon battery will still work if you change the lemons?
2.) Try cutting the lemons in half, or squeezing them and putting the wires in the lemon juice. Does your battery still work?
3.) Since lemon juice is an acid, think about how you can make batteries out of other acids, like orange juice or cola. Or see if your battery will work using a base, like soapy water.
4.) Choose one thing to change (that’s the variable) and predict what you think will happen.
5.) Then test it and if you come up with some cool discoveries.
In his lifetime, Edison invented more than a thousand devices including the phonograph and the light bulb. He also originated the proverb “Genius is one percent inspiration and ninety-nine percent perspiration.”
