Name ____________________________________ Date __________________ Computer

15B

Middle School Science with Vernier 15B - 1

Ziplock Ice Cream

As you have just learned, the freezing temperature of water is lowered when salt is added. You are going to make ice cream by cooling a milk, sugar, and vanilla mixture in a bag surrounded by a bag with an ice and salt mixture. The ice cream mixture will be cooled enough to freeze as heat is transferred from it to the ice and salt mixture.

MATERIALS Ice Cream Bag Ice Bag 1 liter-size (1 quart) Ziplock freezer bag 4 liter-size (1 gallon) Ziplock freezer bag 250 mL (1 cup) milk 90 mL (6 tablespoons) table salt 30 mL (2 tablespoons) sugar, or equivalent 2 double handfuls of ice

sweetener for diabetics 250 mL (1 cup) water 5 mL (1 teaspoon) vanilla Also Needed cup or bowl spoon

PROCEDURE CAUTION: If you have medical problems with any of these ingredients, see the teacher.

1. Put the milk, vanilla, and sugar into the smaller bag.

2. Seal this bag after squeezing out most of the air.

3. Put the ice, salt, and water into the larger bag.

4. Place the “ice-cream” bag into the “ice” bag and seal the “ice” bag.

5. Hold the top corners of the “ice” bag and gently slosh it side to side. Do this gently, or the bag could break.

6. Slosh until the contents of the bag start to get firm.

7. Mix the contents of the “ice-cream” bag by squeezing it to keep the ice cream from being both frozen and runny.

8. Slosh until the “ice cream” has the feel of play dough.

9. Remove the “ice cream” bag. Empty the “ice” bag into a sink.

10. Very quickly rinse the “ice cream” bag with cold water to wash off some of the salt.

11. Do not open the bag! Cut off one of the lower corners and squeeze the ice cream into a cup and enjoy it. Note: Do not eat directly from the bag. This melts the ice cream quickly and causes a mess!

Evalua

tion co

py

Vernier Lab Safety Instructions Disclaimer

THIS IS AN EVALUATION COPY OF THE VERNIER STUDENT LAB.

This copy does not include:

� Safety information

� Essential instructor background information

� Directions for preparing solutions

� Important tips for successfully doing these labs

This lab is intended for students ages 13 and older. For students ages 12 and under, we recommend that teachers perform the experiments as demonstrations.

The complete Middle School Science with Vernier lab manual includes 38 labs and essential teacher information. The full lab book is available for purchase at:

http://www.vernier.com/cmat/msv.html

Vernier Software & Technology

13979 S.W. Millikan Way • Beaverton, OR 97005-2886 Toll Free (888) 837-6437 • (503) 277-2299 • FAX (503) 277-2440

info@vernier.com • www.vernier.com