All of the Sophomore Chemistry classes at SKA recently had the opportunity to participate in an ice cream lab, which was a huge success. Our teachers taught us that in order to have a phase change in matter, heat must be gained or lost, which we see in our everyday lives. In this experiment, we were able to see how fast heat is lost in order to change the milk from a liquid to a solid state. This is also an example of a physical change in matter. We first took the milk, sugar, and vanilla and poured it into a small Ziploc bag. Next, we took a large Ziploc bag and filled it up with ice cubes. Then we put the small bag into the large bag and started flipping it.
My classmates had a great time throwing the bag around and around. When we saw that nothing was happening, we then added salt. Adding a solute, like salt, to water lowers the freezing point of water from 0 ̊C to about -10 ̊C or lower. The salt water then has a lower freezing point than pure water and stays liquid at very low temperatures. As 10-15 minutes went by, we saw our ice cream forming and removed the small bag from the large one.
We then took our ice cream out and put it into bowls and added our favorite ice cream toppings. Everyone grabbed a spoon, took their ice cream outside, and enjoyed! Thank you, Dr. Kimmel, for organizing this super cool and extremely yummy lab experiment!
By Naomi Sigman, SKA 10th Grade