I scream. You scream. We all scream for ice cream!
We had our best turn out for Science Saturday. The park was full of little chemists learning how to cool their ice cream mixture using salt + ice (it works by lowering the freezing point of water). Here's the basic ice cream in a bag lesson. We tried reducing the amount of cream and tried a single baggie for the ice cream mixture (instead of double). The recipe worked very well with all milk and with milk/cream combination. Some parents opted to go with a reduced sugar recipe (using 1 T instead of 2 T), and there were no complaints.
If you're doing this on a larger scale: For about 30 kids, we needed about 30 pounds of ice (1 lb/person), 12 lbs (three 4 lb boxes) of ice cream rock salt, 2 gallons of milk, and 1/2 gallon of cream. Since we used the remainder of our bulk vanilla, so I can't tell you how much. It was probably at least 2 oz. The recipe uses a pretty minimal amount of sugar, so a small box/bag of sugar will definitely suffice. We also had some mix-in like sprinkles and mini chocolate chips.
Experiment on your own! You can try other ice cream recipes. This method to make quick ice cream should work in theory on anything you'd put in an ice cream maker. Enjoy a cool summer treat while learning about science.
Sorry, I was too busy with ice cream making that I didn't get a chance to take pictures of the event. Trust me, we all had a good time!