Have you ever made homemade ice cream in a bag? It’s a BLAST – and oh so delicious! And the best part? It’s not even difficult. You can find the easy-peasy (and oh so fun) instructions HERE!
It’s an educational opportunity!
So, what is the science behind this activity? From the College of Engineering at Oregon State University –
Salt lowers the freezing point of ice. Ice will melt at 32 °F (0°C), but when salt is added, the freezing point is depressed: a 10% salt solution melts at 20 °F (-6°C). Ice must absorb energy in order to melt. Heat is transferred from the environment (which includes your ice cream mixture) to the ice, making the ice cream mixture colder. You can control how fast the ice cream forms, by modifying the amount of salt you use. You could try rock salt which, with larger crystals, takes longer to dissolve and may result in a smoother ice cream.