Summer is raging on and its getting hot out there! Want to cool down with a yummy treat, and still learn a new thing or two? Believe it or not, creating homemade ice cream involves a great deal of chemistry. Put your STEM skills to the test for this chilly science experiment with a sweet result!
Materials:
- 1 cup of half-and-half
- 2 tablespoons sugar
- ½ teaspoon of vanilla extract
- 3 cups ice
- 1/3 cup kosher salt
- Gallon-sized bags
- Sandwich-sized bags
- Ice cream toppings of your choice
Step One
Using your sandwich-sized baggie, combine the half-and-half, sugar, and vanilla. Be sure to combine it well by shaking it, and then squeeze out the extra air and seal it well.
Ice Cream Chemistry: Even though the half-and-half might already be slightly cold, it isn’t enough to make the ice cream take its desired solid form. These three ingredients all need to be cooled down further. But how?
Step Two
Place the ice in the gallon-sized baggie and add the salt.
Ice Cream Chemistry: The salt lowers the temperature at which water freezes. This bag of salt ice will melt even when the temperature is below the normal freezing point of water. This is the same principle in the wintertime when trucks put salt on slick, icy roads.
Step Three
Place the small bag into the ice-filled bag. Shake it vigorously for 7-10 minutes.
Step Four
Check ice cream to see if its consistency has hardened.
Ice Cream Chemistry: You might need a towel or oven mitts when you shake the bag because it becomes so cold. Due to the vigorous shaking and the ice that is now several degrees below freezing, the liquid has been cooled enough to harden it.
If you tried this experiment without the salt, the liquid would have remained in that liquid state simply because the ice wasn’t cold enough. Who knew the most important ingredient in making bagged ice cream would be salt?
Step Five
Remove from bag, add toppings, and enjoy!
Yum! We love the Summer of Science!
DIY Ice Cream in a Bag!