I wanted to make the clock run on grass, so I tried it, and it worked, but it was dim and only lasted for about a minute. So i tried other stuff, that worked but it was expensive fruit, and for that price you could by a small battery. Later in the week we had a party with soda and i tried soda, clearly because it is called SODA clock it worked, and it was bright. And because you can get soda for 40 cents (food max) I used soda.
Two glass or plastic bottles
lemon clock kit (or pottato etc.)
To make it you will need a/some:
(The blue green dots in the picture are the bottles/soda)
The red wire goes to the copper(in mine).