Did you know that you can use play dough to do electrical experiments? Batteries depend on a difference in conductivity between the anode and the cathode to generate electricity. In the recipe for play dough, you can use either sugar or salt. The salt recipe conducts more electricity whereas the sugar variant has more resistance. Voila. You can make a circuit. Here's AnnMarie demonstrating some experiments you can do with the play dough circuit in her TED University talk.