Lab Activity 7: We All Scream for Ice Cream

Purpose:

To observe the freezing point depression of salt water and its effect on the milk, sugar, and vanilla mixture.

Materials:

-One-cup containers of whole milk -Vanilla extract

-Plastic container of pure cane sugar -Plastic spoons

-Small plastic storage zip-lock bags -Wide mouth plastic cups

-Plastic container of pure table salt

Procedures:

Place one cup of milk, two tablespoons of sugar, and one teaspoon of vanilla extract into a zip-lock storage bag. Make sure that you seal it completely. Shake it up until all the sugar dissolves.
Place crushed ice sprinkled generously with salt into a plastic refrigerator bottle along with the bag containing the milk. Screw on the cap making sure that it is water-tight.
Agitate (shake) the bottle by turning it in different directions continuously until the mixture turns to a solid.
Take out the bag. Place it inside a plastic cup for support. Open the bag and enjoy your “ice cream.”
On your own paper, make a diagram illustrating your ice-cream-making method. Describe your observations in complete sentences. Compare the end result to commercially produced ice cream.
Describe what was happening to the crushed-ice-and-salt mixture in the plastic bottle, and what was simultaneously happening inside the zip-lock-bag. To the best of your ability, explain each change.