Question

Okay so in our class we did an ice cream lab where we use Ziploc bags to make ice cream. We made an ice cream mixture and then put it into a smaller Ziploc bag. Then we got a large Ziploc bag and placed ice in it and placed the bag with the ice cream mixture into the large bag and were told to put salt into the bag and then shake it until it forms ice cream?

Anyway I was wondering what caused the rapid increase in the amount of water in the bags.

Answer 1

salt draws out the water

Answer 2

first off, the ice was colder than OC. Adding salt lowers the freezing point of the "water". But it so the heat from the ice cream mixture melted some of the ice, making more salt solution in the outer bag. But melting that ice requires heat, so heat was taken from the ice salty water, making it colder, reducing temp, and causing the icecream to get colder. As long as the process goes, adding salt and cold ice, it will take heat from the ice cream mixture. Next time you do this, you need a thermometer in the ice cream mix, and a thermometer in the ice bag. You will be amazed how cold it gets as the ice melts in the salt mixtxure.