The Science of Root Beer Floats

In this lesson, children will combine two simple ingredients—root beer and vanilla ice cream—to observe a reaction between a liquid and a solid that releases a gas.

Content Area:

Curiosity and Wonder
Physical Properties

Learning Goals:

This lesson will help toddlers and preschoolers meet the following educational standards:

  • Demonstrate curiosity about the world and begin to use the practices of science and engineering to answer questions and solve problems
  • Explore concepts and information about the physical, earth and life sciences
  • Understand important connections and concepts in science and engineering

Learning Targets:

After this lesson, toddlers and preschoolers should be more proficient at:

  • Developing and using models to represent their ideas, observations and explanations through approaches such as drawing, building or modeling with clay
  • Deriving meaning from experience and information by describing, discussing and thinking about what happened during an investigation
  • Experimenting with the changes that matter undergoes when combined with other substances
  • Using nonstandard and standard tools for scientific investigation
toddler planting

The Science of Root Beer Floats

Lesson plan for toddlers/preschoolers

Step 1: Gather materials.

  • The book, Change It!: Solids, Liquids, Gases and You by Adrienne Mason
  • Root beer
  • Vanilla ice cream
  • Ice-cream scoop
  • Clear plastic cup
  • Clear spoons

Note: Small parts pose a choking hazard and are not appropriate for children age five or under. Be sure to choose lesson materials that meet safety requirements.

Step 2: Introduce activity.

  1. Read the book, Change It!: Solids, Liquids, Gases and You by Adrienne Mason
  2. Explain that today we are going to make predictions, hypothesize and test out our theories on states of matter.
  3. Explain that root beer is a carbonated beverage. Root beer is a liquid that takes the shape of a container. When you add ice cream (a solid) to the root beer, the ice cream reacts with the root beer and releases carbon dioxide (gas) bubbles. Since the root beer is trying to free up the air bubbles in the ice cream, it creates a bubbly foam that rises to the top of the jar. Ask: “How is a solid different than a liquid?”
  4. Tell the children: “From this experiment, you will learn that there are three forms of matter:
    • Solids have their own shape and form (like the scoop of ice cream in our experiment). The molecules in solids are tightly coupled.
    • Liquids take the shape of their container (similar to the root beer in our experiment). Liquids have molecules that are close together, but not as close as the molecules in solids.
    • Gases have no shape or form (like the carbon dioxide released in our experiment). The molecules in gases are loosely coupled and farther away from each other than the molecules in liquids and solids.
    • A root beer float is made up of all three states of matter: a solid (ice cream), a liquid (root beer) and a gas (creamy foam).

Step 3: Engage children in lesson activities.

As you follow the steps below, ask the children to predict what will happen:

1. Put a scoop of ice cream in your cup. (You can prep for this step before class: Fill the cups, place them on a tray and put them back into the freezer.)

2. Slowly add the root beer until the cup is three-quarters full.

3. Observe the foam as it rises. Discuss your observations and enjoy your root beer float!

Step 4: Vocabulary.

  • Freeze: To harden nto a solid 
  • Gas: A form of matter that has no fixed shape and tends to expand without limit
  • Liquid: A form of matter that flows  freely like water
  • Solid: A form of matter that keeps its size and shape
  • States of matter: The three most familiar states are solid, liquid and gas 

Early Science Glossary

Step 5: Adapt lesson for toddlers or preschoolers.

Adapt Lesson for Toddlers
Toddlers may:
  • Prefer less root beer and more ice cream
  • Not comprehend the concept behind the experiment, but they can still enjoy the ice cream!
Child care providers may:
  • Take this activity outside and have water play nearby for clean up
  • Realize that this topic is too complex young brains
Adapt Lesson for Preschoolers
Preschoolers may:
  • Investigate variables such as: “Does it make a difference if the root beer is warm or cold? What happens if you put root beer in the glass first? What happens if you use glasses of different shapes and sizes? What happens if you use root beer that has lost its fizz?
Child care providers may:
  • Conduct this experiment on the final day of an academic calendar year or another day of celebration

Suggested Books

  • Curious Pearl Explains States of Matter: 4D An Augmented Reality Science Experience by Eric Mark Braun (author) and Stephanie Dehennin (illustrator)
  • What is the World Made Of?: All About Solids, Liquids and Gases by Kathleen Weidner Zoehfeld and Paul Meisel


Music and Movement

  1. Gather the children together and ask them to hold hands very tightly and say: “Solids are made of particles that are very close together.”
  2. Then ask them to stretch their arms out while continuing to hold hands and say: “Liquids are made of particles that are farther apart.”
  3. Finally, ask the children to stand with their fingertips barely touching and say: “Gases are made from particles that are barely touching one another.”
  4. By turning this into a game, you can teach young children about the states of matter. Organize the children into small groups.  Call out “Solid” and direct the children to move in close while holding hands tightly. Call out “Liquid” and direct the children to move outward while still holding hands. Call out “Gas” and instruct the children to move farther apart so that their fingertips are just touching.


Outdoor Connections

This is a great outdoor activity for a hot summer day!

Web Resources

View “States of Matter for Kids” for a fun introduction to the different states of matter.


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