1. Ice Cream in a Bag! Estimated Time: 40 min Grade Level: 8-9 Subject: Introductory Chemistry

2. Getting Started Is the making of ice cream chemistry? What ingredients are in ice cream? Today we are going to do an experiment on the science of making ice cream. Work in pairs!

3. Materials (per pair) 1 qt. resealable bag 1 gallon resealable bag ½ c. sugar 1 c. milk 1 c. whipping cream ½ tsp. vanilla ½ c. rock salt 12 ice cubes winter gloves or mittens 2 plastic cups 2 plastic spoons

4. Procedure (1) 1. Add the sugar, milk, whipping cream, and vanilla to the quart bag. Make sure the bag is completely sealed with as little air inside as possible. 2. Add the rock salt and ice cubes to the gallon bag.

5. Procedure (2) 3. Place the sealed quart bag into the gallon bag and then seal the gallon bag. Again, make sure the bag is completely sealed with as little air inside as possible. 4. Put your gloves or mittens on… our goal is to freeze the ice cream, not your hands!

6. Procedure (3) 5. Gently shake the bag so that the ice is continually moved around the milk mixture. 6. When the milk mixture is frozen, take the quart bag out of the gallon bag and wipe it off with a paper towel. Pour the ice/salt mixture from the gallon bag into the sink.

7. Procedure (4) 7. Distribute the ice cream evenly between your two cups and enjoy your treat while you answer the following questions… Please remember to clean up your area after you are finished!

8. Questions (1) 1. How many phase changes did you observe in this experiment? 2. What would happen if you didn’t add salt to the experiment? 3. What happened to the ice in the outside bag? Why?

9. Questions (2) 4. Why do some people sprinkle salt on icy sidewalks? 5. List a question you thought of during this experiment and describe a procedure that you could do to answer the question.

10. Clean-Up! Please leave your workspace as clean or cleaner than you found it!