To learn about the currency used to represent precious metals head to the Chicago Fed's Money Museum. Economics is an intangible concept and can be difficult to learn so the Money Museum attempts to put the concepts into an interactive format. There are games and simulations that show how the Federal Reserve works and how money changes over time. It's a great place to take kids to pique their interest in how money works. They'll learn about inflation, paying bills, and saving cash. Admission is free which is a great way to start teaching the kids how to keep spending to a minimum.