What household objects can you apply physics to?

I'm doing a project for my High School Physics class, and I was wondering if anyone can give me some ideas. I have to find 12 items (any kind, but I chose household items), and find out how physics applies to it. If you could give me a list of items you know physics applies to, and if possible how it applies that would be great. Thank you!

Most every household device applies an area of physics in one way or another. For example, the speakers on your sterio use an expanding and collapsing magnetic field to vibrate the air and produce sound. Go through your home and look at all of the mechanical and electrical devices that make things work. They all have springs, relays, latches and motors. How does an air conditioning system change the temperature of air? How does a microwave oven heat food? What about a refrigerator or washing machine? A really cool one is a smoke detector that will detect gas in the air. There's enough physics in the computer you're using to write a book but if your name is going on the project, you should do the thinking, not Ehelp.