After making ice cream, students will be able to show how salt lowers the freezing
point of water.....
You will need:
Milk, Cream, or Half & Half
Vanilla extract or Chocolate syrup
baggies (ziplock) (large and small sizes)
Start introducing the lesson by talking about the freezing point of water. Speculate if there is any way
to make that lower. Ask if students know what the stuff is that they put on the road in the winter
here in Minnesota.
Discuss the fact that we put salt on the roads to help melt ice and prevent slippery conditions. (Salt
lowers the freezing point of water.) You can also describe how this allows us to make ice colder by
adding salt. You can demonstrate this, or do small group investigations by using a thermometer in a
plain cup of water, then adding just ice, then salt to it.....the students can record the temperature for each step.
Making ice cream:
Each student gets a sandwich size ziplock baggie to which these ingredients will be added...
One teaspoon of sugar
2 oz. of milk, cream, or Half & Half
a dash of vanilla extract or about 1/2 teaspoon of chocolate syrup.
After the ingredients have been added, seal the baggie and squish everything around to mix it up.
Put three or four of the students baggies into a large ziplock baggie about half full of ice, and with
about 5 oz. of salt... then wrap the big baggie up in newspaper so that it looks like a tootsie roll.
Have two students take one end each, and shake the 'tootsie roll' for about 5 min.
You now have ice cream!!!! Pass out spoons and eat!