Homemade Ice Cream
Objectives: Students will learn about heat transfer by making their own homemade ice cream.
1 sandwich-size Ziploc bag
1 tennis can/cover
1 paper cup of table or rock salt
2 plastic spoons
Ice cream ingredients
1 cup homogenized milk
2 tablespoons sugar
1/2 teaspoon vanilla
chocolate syrup (optional)
- Place the ice cream ingredients in the small zip lock bag, seal with as little air as possible and mix well.
- Place some ice in the can with half of your salt.
- Place the small bag in the can.
- Fill to the top with ice, and add the rest of your salt. Record the temperature of the ice and salt before shaking.
- Shake or roll your can to mix the ice and salt. You may add more ice if needed, but no more salt should be necessary.
- After four minutes open can and record temperature of ice salt mixture.
- Continue to mix until ice cream is the desired consistency. (about 5-10 minutes more)
- Open the can and remove the small bag, rinsing it (the bag) carefully with tap water before opening.
- Rinse thermometer, open small bag and record temperature of the ice cream mixture.
- Eat ice cream!
- VARIATION: This experiment may be varied by using chocolate milk or condensed milk in place of homogenized milk or adding chocolate syrup to the milk.
Closure: Conclusions (for report)
- Draw a diagram of the baggie-ice cream freezer. Add arrows to the diagram to indicate the direction of heat transfer (i.e. from the ice cream to the salt mixture or vice versa).
- How many minutes did it take for your ice cream to freeze?
- Was the process by which the milk mixture turned into ice cream exothermic or endothermic? Explain, including what was happening to the ice and salt mixture.
- Is this process a chemical or physical change?
Evaluation: Were students able to answer the conlcusion questions?
Source: Mary Lisa