World’s Easiest DIY Electric Train

One of the things that I like about physics is the benefit of tactile interaction when learning a new concept. At least for Newtonian physics, it's better to get out and "play" by doing physics demonstrations before sitting down and doing the math. Virtual environments can also work well as a playground. Want to learn orbital mechanics? Play with Kerbal Space Program first, then go learn the equations. It's a faster and better way to understand the concepts, and makes it easier to use the math properly.