Sweet and Salty: Scream for Ice Cream
Source: NOAA National Weather Service
[31-May-2022] Who doesn't want ice cream while concurrently conducting science experiments? During this 30-minute challenge, students will have a sweet chance to learn about the basics of salinity, the freezing and melting points of a liquid, and ice and salt crystal formation. Fresh water freezes at 32°F (0°C), but adding salt to water lowers the freezing point of the solution. How low the freezing point dips depends upon the amount of salt in water. The students will make homemade ice cream but the "freezing times" will vary using different amounts of salt to lower the freezing point of water. A directed discussion afterwards helps students apply their new knowledge to a range of salty bodies of water around the world (from the Great Salt Lake to the Dead Sea), as well as speculate on the winter-time practice in more Northern climes of adding salt to icy roads.
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