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Making Ice Cream

1. Overview
2. Introduction
3. Materials
4. Instructions
5. Activity Questions
6. Assessment
7. Suggestions for Expanding the Activity
8. Learning Standards
   • Early Elementary
   • Late Elementary
   • National Standards

Overview

During this hands-on activity, students will be able to make their own ice cream. This activity demonstrates concepts related to states of matter and the inclined plane, a simple machine. This activity is simple and inexpensive, yet it provides endless possibilities for lesson expansion and fullfillment of learning standards. This lesson will take approximately 90 minutes. Lesson design by Rachel Jordan and Brian McMillan.

Introduction

The concepts that will be focused on for this lesson are states of matter and the inclined plane.

Background Information:

Molecules with a lot of energy move faster and take up more space than molecules with a smaller amount of energy. Heat is a form of energy that can be used to study this phenomenon. For example, in the diagram below, the gas molecules are taking up more space than the solid or liquid molecules.

In this activity, salt is used to help make the ice cream. Salt dissolves in water and decreases the freezing point (the temperature when water turns to ice). Salt water will freeze below 32 degrees Fahrenheit (0 degrees Celcius).

Here are some potential discussion questions:

1. 1. What provides energy for molecules to move?
2. 2. Do gasses, such as steam, have more or less energy (heat) than liquids, such as water?
3. 3. Do liquids have more or less energy (heat) than solids, such as ice?
4. 4. If energy (heat) is reduced, can we convert a gas into a liquid? A liquid into a solid?
5. 5. Why do road workers put salt on the roads after it snows?

To make ice cream, you will need the following materials for each student:

• one teaspoon of sugar
• 1/4 cup milk
• 2 drops vanilla extract
• measuring cups and spoons
• 1 locking sandwich bag
• 1 locking quart-size bag
• 2 cups of ice
• 1/2 cup of rock salt
• one sheet of newspaper
• metal coffee can with lid
• inclined plane (ramp, slanted board, table)

Note: Newspaper and rock salt are not shown

Instructions

Put one teaspoon of sugar, 1/4 milk, and 2 drops of vanilla extract in the locking sandwich bag.

Seal the sandwich bag. From the outside of the sandwich bag, squish the bag repeatedly to mix the contents.

Put 2 cups of ice, 1/2 cup of salt, and the sandwich bag in the quart-size locking bag.

Wrap the quart-size bag in a sheet of newspaper and place it in the metal can. Place the lid on the can.

Roll the cans up and down the inclined plane to mix up the milk, sugar, and vanilla further. Continue rolling until the mixture hardens. The time required for the mixture to harden will vary depending on the temperature of the surroundings.

Enjoy!!!

Activity Questions

1. Which ramp made the can roll the fastest? Why?
2. Why did we put salt in the large locking bag?
3. Was the water a gas, liquid, or solid when it formed on the metal can? Where did this water come from?
4. Why did water condense on the outside of the metal can?
5. What does adding salt to water do to the freezing point?
6. How can you turn a gas into a liquid?
7. How can you turn a solid into a liquid?
8. Do solids have more or less energy than gases?
9. What do you think the molecules of liquid milk would look like? Draw a picture below.
10. What do you think the molecules of solid ice cream would look like? Draw a picture.

Assessment Background

Our assessment methods were the same for Illinois and National Standards.

Our assessment methods were the same and for Early and Late Elementary School students. What changed was the level of the questions asked and the discussion.

During the Lesson

The participants used inquiry strategies to successfully determine how to make ice cream. To broaden the activity, participants tested different flavors ans aldo varied the time they rolled the can. Throughout the lesson, the participants discussed the inter-relationships between science, technology, and society.

At the End of the Lesson

At the conclusion of the lesson, a discussion was held to determine the level of participant understanding of how ice cream is made. The discussion also encouraged students to think critically about how ice cream is used in society.

Here is a sample of questions from that discussion:

• Why did water condense on the outside of the can?
• Where did this condensed water come from?
• Why did the contents in the bag harden into ice cream?
• How could the temperature or humidity effect this activity?

Each of the children who participated in the lesson was able to answer these questions at his/her own level.

Here are some suggestions to add variety to the activity.

1. Vary the flavoring. Other flavors besides vanilla can be used. For example, try adding chocolate syrup, lemon juice, fruit juice, mint extract, etc. Caution: adding a large amount of liquid (i.e. chocolate syrup) may affect the formation of the ice cream.
2. Use different inclined planes. Using planes of different shapes, sizes, and inclines will allow students to make conclusions as to the effectiveness of varying planes.

Here are some sites for additional ways to make ice cream, or to get ideas for exotic flavors!

• The Ice Cream Parlour: A good site for exotic flavors and things to add to your ice cream.
• Make Ice Cream.com: This site focuses on making ice cream mith a machine. If you have one, you will enjoy this site!
• 4 Ice Cream.com: This site has recipes for ice cream, and also talks about what flavors are the most popular today.

Illinois State and National Learning Standards that Apply to this Lesson

The following standards are from the Illinois Learning Standards, adopted by the Illinois State Board of Education on July 25, 1997. Take a look at the complete Illinois Learning Standards for Science, and for English/Language Arts.

Early Elementary

Late Elementary

National Learning Standards that Apply to this Lesson