water. 77) two bottles of water filled with the same amount. put some salt on top of the ice cube and then lay some string on top. when you stop shaking the balloon the penny will continue to spin. 74) penny in a blown up balloon-shake the balloon and the penny will start to spiral around. you can stick a pencil right through it. . drop water on top and watch to see what happens. 79) get a flat plate and fill it with full fat milk. 75) a plastic bag with water in with a seal. give them a minute to generate static electricity from their clothes or hair 