Ice Cream

My Physical Science kids got a real treat today. They got to make homemade ice cream. The unit we are covering now is all about elements and bonding so I pieced together a totally awesome lab on making homemade ice cream. The lab went in to the differences between ionic bonding (the rock salt you need to freeze the ice cream), and covalent bonding. I also talked about freezing points, melting points, and the differences between compounds and mixtures. (Once you lower the temperature of the ice cream, it changes state.)

The lab was a big set-up. We don't have our own ice machine so I had to make 3 different trips to the cafeteria to get garbage bags full of ice and haul it back to my room. No biggie, extra exercise for me!

Once the lab was written, it was pretty easy to do in class. It took the entire 50 minute class period and the kids really enjoyed it. Some of the girls were not too keen on getting their hands that cold (since the temperature of the bag drops to -12 degrees Celcius) and can be painful. The boys LOVED it. They were acting all macho and kneading the girls ice cream bags for them. It was pretty funny. The lab was a DISASTER at the end of the day and I offered extra credit to anyone who stayed late or came in after school to help me clean up..... no one showed. So, I spent quite awhile cleaning up!

If you even want to do it at home, it is so simple. Follow the mixture below and if you are a teacher, email me or respond to this post and I will send you the lesson plan.

1 Gallon size Ziploc Bag
1 Quart size Ziploc Bag
1/4 c. Rock Salt
5 C. Ice
1 C. Whole Milk
1/4 tsp. Vanilla - (or you could substitute chocolate syrup, strawberry syrup, or any flavoring you like)
6 sugar cubes (I am so glad I used sugar cubes because they didn't make such a huge mess!)

In the quart bag, mix your milk, vanilla, and sugar. Get as much air out as possible and seal the bag tightly. In the gallon size bag, mix the ice and rock salt. Place your quart size baggie inside the gallon baggie with the ice & salt mixture. Get as much air out as possible and seal the bag. Shake the bag and knead it like crazy for about 7-10 minutes. Some of my kids had gloves or used their jacket to wrap the ice cream bag in so they could knead it without freezing their hands. If your ice cream doesn't harden, add more ice and KEEP KNEADING. Knead it like crazy consistently without stopping! Once your ice cream starts to harden, get a spoon and dig in!

They LOVED the lab = awesome day + a lot of work for me!

P.S. The analysis/conclusion questions they were supposed to answer in complete sentences and turn in at the end of the lab...... out of a class of 32, I am ball-parking that I got 6 who actually turned them in for each class.