Here's a delightful science/cooking project for kids: turning cream into butter and whipped cream! The only equipment you need is a whisk and a jar (no churn required; though that might be more efficient.) In the video below, a group of Brownies do a bit of science and play, learning how and why cream transforms into these alternate forms. This is adorable, and you can actually learn something from it. Enjoy:

You can also download the info-sheet (PDF) for more on the activity and the science behind it.

If you're more into industrial butter production, check out this How It's Made video: