How to Make Ice Cream for a Science Experiment

Salt plays an important role in ice cream making.

While it may sound strange, the ice cream making process can be used as a science experiment to show the effects of a chemical reaction. A traditional method of making ice cream uses salt and ice as the cooling agent. When salt is added to ice, it lowers the ice freezing point and ultimately causes a temperature drop, which makes the ice feel colder. This temperature change enables the liquid ice cream mixture to freeze in less than half the time it would take in a conventional freezer.

Things You'll Need

• 1 gallon plastic jar
• Crushed ice
• 6 tbsp rock salt
• Towel
• 2 quart-sized sealable plastic bags
• ½ cup cream
• 1 tbsp white sugar
• ½ tsp vanilla extract

Instructions

1. Fill a 1 gallon plastic jar half way with crushed ice. You can also use snow if you happen to have some in your yard.

2. Add 6 tbsp of rock salt to the jar. Screw the lid on the jar.

3. Wrap a towel around the jar to protect your hands from the cold. Shake the jar vigorously for five minutes to thoroughly combine the ingredients. During this time, the temperature can drop by almost 20 degrees Fahrenheit.

4. Add ½ cup of cream, 1 tbsp of white sugar and ½ tsp of vanilla extract to a quart-sized sealable plastic bag. Squeeze as much air out of the bag as possible and seal it.

5. Place the bag inside a second sealable bag of the same size. Again, squeeze out as much air as possible and seal the bag.

6. Add the bags to the jar with the ice and salt mixture. Screw the lid back on the jar.

7. Wrap the jar in a towel. Shake the jar for 15 to 20 minutes, or until the cream mixture thickens. The final result should look like soft-serve ice cream.

References

• Steve Spangler Science: Making Ice Cream With Snow