There’s no need for expensive, high-tech lab equipment to conduct chemistry experiments—you probably have all you need in your home junk drawer. Turn an old LED flashlight into an Energy Drink Tester using aluminum foil and electrical tape. Mix cornstarch and water to make Non-Newtonian Goo. Use a 9-volt battery and thumbtacks to break water molecules into hydrogen and oxygen. Create edible Sweet Crystals from a saturated sugar solution. Or construct your own Three-Penny Battery from galvanized washers, pennies, vinegar, and scrap cardboard.             Here are more than 50 great hands-on experiments that can be performed for just pennies . . . or less. Each project has a materials list, detailed step-by-step instructions with illustrations, and a brief explanation of the scientific principle being demonstrated—atoms, compounds, solutions, mixtures, reactions, thermodynamics, acids and bases, and more.