Need HELP with Ice cream questions!!!! =)

[Unregistered]

I am new at this.. Just starting to teach in the classroom. I am teaching a lesson on physical changes in matter (from liquid to solid) using ice cream to 4th graders. I don't know how I would explain those concepts to 4th graders--seems rather difficult. How the salt works to change the matter? Need help coming up with good discussion questions!!!! Thanks!! =)

[Unregistered]

Is the salt relevant to the lesson? Is this a lesson on states of matter, or chemistry?

[Instructorus Rex]

I am new at this.. Just starting to teach in the classroom. I am teaching a lesson on physical changes in matter (from liquid to solid) using ice cream to 4th graders. I don't know how I would explain those concepts to 4th graders--seems rather difficult. How the salt works to change the matter? Need help coming up with good discussion questions!!!! Thanks!! =)

Salt lowers the freezing point of water which causes the ice to "melt" by making it colder. It's a tough sell just using words so try making some ice cream in class (it's pretty easy).

1. Mix 1/2 cup milk, 1 Table spoon of sugar, & a few drops of vanilla extract in small ziplock back and seal

2. Place ice & rock salt into large ziplock bag

3. Seal the small back of ingredients inside the back of ice and mix vigorously for about five minutes until your get some ice cream!



The rock salt will drop the melting temperature of the ice, causing it to melt. The resulting liquid water/salt solution will be significantly colder than 32 degrees which will cause the milk, sugar, and vanilla to freeze into ice cream.