Ice Cream in a Baggie by Bryce Hixson
This is a slam-dunk, four-star, tell-Mom-about-it-the-minute-you-hit-the-back-door lab activity. The kids combine three liquids and two solids in a bag. The contents are then mangled, agitated, cooled, and eventually frozen into a friendly pile of homemade ice cream. Great for teaching solids, liquids, and gasses.