The Engineering Place (K-20 Outreach)

Ice Cream in a Bag (1st-3rd)

Lesson plan developed by Elizabeth Goodson

Objective: The students will observe matter change states using the scientific method as a tool.

Overview: This lesson will emphasize the scientific method, changes of matter and temperature.

Materials:

• Milk or cream (2 oz for each student)
• Vanilla extract or chocolate syrup
• Sugar (1 tsp for each student)
• Ice
• Salt
• Plastic re-sealable bags (large and small)
• Newspaper
• Spoons

Getting Ready: Pre-measure all ingredients.

Activity: Possible questions to ask are as follows:

1. We have talked about the 3 states of matter — What are they?
2. We have talked about how matter changes states — from gas to liquid to solid: through temperature.
3. What happens when a liquid changes temperature and becomes a gas — boiling point?
4. What happens when we change the temperature of water and it becomes a solid — that temperature is the freezing point.

• We are going to see if we can make a liquid milk turn into solid-like ice cream by lowering the temperature to the freezing point.
• I want us to approach this like scientist.
• What method do scientists use to do an experiment?
• Explain Scientific Method:
  • Scientific Method is a way to look at something like a scientist looks at it by performing an experiment.
  • The different steps are the following:
    1. Observe and ask questions.
    2. Make a hypothesis.
    3. Plan your test.
    4. Conduct your test and gather data.
    5. Draw conclusions and share results.
    6. Investigate further.

Procedure:

1. Give each student a small bag
2. Add the following ingredients for each student
   • 1 tsp of sugar
   • 2 oz of milk or cream
   • a dash of vanilla or ½ tsp of chocolate syrup
3. Seal the bag
4. Squish or Mix everything together
5. Place 3-4 students bags in a larger bag that is about half filled with ice and 5 oz of salt
6. Wrap the large bag up in newspaper and twist the ends
7. Have 2 students take each end and shake the roll for about 5 minutes

Closing:

Why did some bags of ice cream freeze quicker than others?

Would twice as much ice have made it freeze twice as fast?

What would have happened to the freezing time if we didn’t have salt?

Resources: http://askeric.org/Virtual/Lessons/Science/SCI0018.html

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