Ice Cream Lab

ICE CREAM LAB

Problem: When you make ice cream what is the purpose of the salt that is added to your ice? You will experiment different ratios with and without salt to see which is the most successful.

Pre-Lab Questions:

1. What do you think would make a “successful” ice cream in lab? What would you like your ice cream to be like before you eat it?

2. Is making ice cream a physical or chemical change? Explain why.

3. What is the change of state that is occurring when you make ice cream? Is it exothermic or endothermic? Explain why.

Make your hypothesis:

What ratio of salt to ice do you think will produce ice cream the fastest, and give the reason why you think this. 

Procedure:

1. Place 6 cups of ice in your milk jug.

2. Measure your salt on the scale as listed in your assigned ratio below. 

3. Place your salt with your ice and shake up your jug to mix it up.

4. Take your tin can to Ms. Cotta to fill with the ice cream solution.

Ratio                   Amounts

0:100                  no salt, 6 cups of ice

1:10                    40 g salt, 6 cups of ice

1:8                       50 g salt, 6 cups of ice

1:5                       80 g salt, 6 cups of ice

1:4                       100 g salt, 6 cups of ice

1:2                       200 g salt, 6 cups of ice

1:1                       400 g salt, 6 cups of ice

5. Push your tin can down into your ice and salt mixture so that it is surrounded by ice cream on the sides and underneath.

6. Put your thermometer into the ice (NOT THE ICE CREAM) and measure the initial temperature of the ice.

7. Stir your ice cream regularly with the wooden stick so that it will freeze evenly. The bottom and sides will freeze first.

8. Every five minutes check the temperature of the ice and write it in your data table.

9. Check the consistency of the ice cream and write and observation such as runny (still like milk), thin (little frozen pieces), thick (almost frozen).

10. After 30 minutes you may dish out your ice cream to you and your partner and try it out.

Data Table

Salt to Ice Ratio (write your ratio)	0 mins	5 mins	10 mins	15 mins	20 mins	25 mins	30 mins
Temperature
observation (runny, thin, thick)

Clean-Up:

1. Wash out your tin can and replace at your table.

2. Wash out your milk jug in the sink and replace at your table.

3. Wash out your bowls (IF THEY ARE PLASTIC) and recycle them in blue bin.

4. Throw out your spoons and wooden stick.

5. Wipe down your table with a sponge if needed.

Conclusion:

Use the following words to explain this experiment to someone else in a short paragraph: freezing, melting, temperature, ice cream, mixture.  Please underline each of these words in your paragraph.

Questions:

1. Why did the ice cream solution freeze? What is required to turn your liquid to a solid?

2. Which ratio makes ice cream the fastest? What is your evidence for this?

3. What is the purpose of the salt? Would this work without salt? What is your evidence?

4. What was the change of state that occurred? Is it a physical or chemical change? Why?

5. What is the variable (the thing that changes) and controls (the things that stay the same) in this experiment?

6. Draw a model showing what your ice cream mixture was like when it was first place in the ice and then a second model showing it at the end of 30 minutes. Show the speed of the molecules and explain which way the heat is flowing.