Lab # 2-3
Title: I Scream, You Scream, We All Scream for Ice Cream!
Materials: Each group needs the following supplies:
1 small plastic bag
3 tablespoons of sugar
1 large plastic bag
ice
1 cup of milk
salt
½ teaspoon vanilla
cups, spoons and GLOVES
Purpose: To reinforce the concepts relating to Solid, Liquid, Mixture, Pure Substance, Compound,
Chemical and Physical Properties, Chemical and Physical Changes, Freezing Point, Condensation, States of
Matter, Energy changes involved in changes of matter.
Procedure:
1.
Into your small zipper bag pour 1 cup of milk, ½ teaspoon of vanilla, and 3 tablespoons of
sugar. Carefully seal the bag and swish it around to mix thoroughly.
2.
Place the small sealed bag into the large bag.
3.
Add enough ice to the large bag to surround the small bag and add ¼ - ½ cup of salt to the large
bag. Seal the bag.
4.
Carefully knead, or continually flip the large bag so that you “churn” the ice cream. The ice
should be continually moved around the ice cream mixture. Caution: be sure not to add too
much pressure or you may break the bags and you will need to clean up your mess. Make
observations of your ice cream.
5.
Continue this for the next 10-15 minutes. While you take turns and wait for this time to pass
review the definitions of the terms listed above in the Purpose. Also, try to determine why
each of these terms is important for this activity.
6.
Quickly rinse the small bag in cold water to remove the salt from the outside of the bag. Cut off
one corner of the small bag and squeeze ice cream into some cups.
7.
Make observations of your ice cream and then EAT IT with spoons!
8.
Clean up by throwing cups and spoons into the trashcans. Also, throw away the small plastic
bag and any towels you used to clean up. Please place the empty, large plastic bag on the drying
rack if there are no holes in it, if there are any holes, throw it away as well.
Questions:
1.
Why was it necessary to swish the milk after adding the other ingredients?
2.
What type of mixture is ice cream?
3.
What was the purpose of the salt?
4.
Why do we use ice in making ice cream?
5.
Why did you end up with a greater volume of ice cream than what you started with?
6.
What state of matter was the milk when you began?
7.
What state of matter was the milk when you were done?
8.
In order to change milk into ice cream, what had to be removed?
9.
If you had left out the sugar, would the ice cream have frozen faster or slower?
10.
How could you make your ice cream taste better?
11.
Assuming your large bag was not leaking, why did the outside bag come wet?
12.
What would happen if you didn’t add salt to the ice?
13.
Why do ice cream makers have two containers, one that fits inside the other?