Hot, Cold, and Squishy: Exploring States of Matter

Materials Needed

• Ice cubes
• Clear cup or bowl
• Water
• Adult-supervised source of heat, such as a kettle or saucepan
• Clear heat-safe cup or bowl for observing steam
• Cornstarch
• Water for making oobleck
• Large tray or shallow bin
• Spoon or measuring cup
• Food coloring, optional
• Towel or wipes for spills
• Paper and crayons, or a simple observation sheet

Lesson Overview

Age: 4 years old

Time: 35–45 minutes, with the option to divide the lesson into two shorter activities

Big Idea: Matter can change when it is heated or cooled. Some materials behave in surprising ways.

Learning Objectives

By the end of the lesson, the child will be able to:

• Name three familiar states of matter: solid, liquid, and gas.
• Describe what happens when ice is warmed.
• Observe that water can become water vapor, or steam, when heated.
• Make and explore oobleck safely.
• Use simple scientific-method words: question, guess, test, observe, and tell.
• Share one observation using words, gestures, drawing, or demonstration.

Success Criteria

The child is successful when they can:

• Point to or name a solid, liquid, and gas.
• Say, “Heat can melt ice into water.”
• Explain that warm water can make water vapor that rises.
• Describe oobleck as feeling hard when squeezed or tapped and runny when held gently.
• Make a guess and tell what happened after testing it.

Safety Notes

• An adult must handle hot water, the kettle, saucepan, and steam.
• Keep the child’s face and hands away from steam. Steam can burn.
• Do not let the child taste oobleck. Keep it away from eyes and mouth.
• Oobleck may clog sinks. Throw it in the trash after it dries or follow local disposal guidance.
• Wash hands after the activity.

Introduction: Hook and Objectives

Hook: Hold up an ice cube and ask, “What do you think this cold, hard ice will become if we keep it warm?”

Let the child touch the ice briefly and describe it. Say:

“Today we are matter detectives. We will look at ice, water, and steam. We will also make a goo called oobleck. We will ask a question, make a guess, test our guess, watch carefully, and tell what we learned.”

Child-Friendly Scientific Method

Use these five simple steps throughout the lesson:

1. Question: What do we want to find out?
2. Guess: What do we think will happen?
3. Test: What can we do to find out?
4. Observe: What do we see, feel, or hear?
5. Tell: What happened?

Body: Activity 1—Heat Changes Ice and Water

I Do: Model the Investigation

Place an ice cube in a clear cup or bowl. Say:

“Our question is: What will happen to ice when it gets warm? My guess is that it will become water.”

Model looking closely without tasting. Point out that the ice is hard and keeps its own shape.

Explain:

• “Ice is water in a solid state.”
• “A solid is hard and keeps its shape.”
• “When heat warms ice, the ice melts and becomes liquid water.”
• “A liquid can flow and take the shape of its container.”

We Do: Watch and Talk

Place the cup in a warm area and check it every few minutes. Ask:

• “What does the ice look like now?”
• “Is it still hard, or is some of it turning into water?”
• “Does the water keep its own shape, or does it take the shape of the cup?”

Invite the child to draw the ice before and after it melts or make marks on an observation sheet.

I Do and We Do: Observe Water Becoming Steam

An adult heats water in a kettle or saucepan. The child watches from a safe distance. The adult may hold a cool, clear cup near—but not touching—the steam so the child can see tiny water drops form on the outside or inside of the cup.

Say:

“When water gets very hot, some water goes up into the air. We call this water vapor. We can sometimes see it as steam. Water vapor is a gas.”

Explain:

• “A gas spreads out and can move through the air.”
• “Heat can change solid ice into liquid water and liquid water into gas.”

Quick Check

Ask the child to match each word with an action:

• Solid: “Show me something hard that keeps its shape.”
• Liquid: “Show me how water flows.”
• Gas: “Show me how water vapor moves up and spreads out.”

Body: Activity 2—Make and Explore Oobleck

Question and Guess

Show the cornstarch and water. Ask:

“What do you think will happen when we mix this powder and water? Will it be runny, hard, or something different?”

Let the child make a guess using words, pointing, or a drawing.

I Do: Model the Mixture

In a tray or shallow bin, mix:

• 2 cups cornstarch
• About 1 cup water, added slowly

Add a few drops of food coloring if desired. Stir slowly until the mixture feels thick but can still flow. Add a little more water or cornstarch as needed.

Say:

“This mixture is called oobleck. It is made from cornstarch and water. Oobleck does not act like an ordinary liquid all the time.”

We Do: Test Oobleck

Try each test together:

1. Tap: Tap the oobleck quickly. Ask, “Does it feel soft or hard?”
2. Squeeze: Pick up a small amount and squeeze it. Ask, “What does it do?”
3. Relax: Open the hand and let it sit. Ask, “What happens when we stop squeezing?”
4. Pour: Slowly let it slide from one hand into the tray. Ask, “Does it flow?”

Introduce the term:

“Oobleck is a non-Newtonian fluid. That is a big name for a goo that can act hard when we push it quickly and act runny when we move it slowly.”

You Do: Oobleck Investigation Choices

Let the child choose one or more tests:

• Make a handprint in the oobleck.
• Try to roll it into a ball, then stop moving it.
• Use a spoon to stir slowly and quickly.
• Place a small toy on top and see whether it sinks or stays on the surface.

After each test, ask the child to complete one sentence:

• “When I moved it quickly, it…”
• “When I moved it slowly, it…”
• “I noticed…”

Scientific Method Review

Use the child’s experiences to review the five steps:

1. Question: What happens when ice gets warm? What does oobleck do when we push it?
2. Guess: What did you think would happen?
3. Test: We warmed ice, watched hot water, and pushed oobleck.
4. Observe: We used our eyes, hands, and words to notice changes.
5. Tell: We shared what happened.

You Do: Final Demonstration

Invite the child to choose one way to show learning:

• Draw ice, water, and steam and explain each picture.
• Sort word cards or household examples into solid, liquid, and gas.
• Demonstrate how oobleck acts when pushed quickly and moved slowly.
• Tell a family member what happened using the sentence frame: “First ___, then ___, because ___.”

Assessment

Formative Assessment

• Listen for the child’s guess before each test.
• Ask the child to point to or name solid, liquid, and gas.
• Observe whether the child notices changes in the ice and oobleck.
• Use prompts such as “What do you notice?” and “What happened when you changed one thing?”

Summative Assessment

Ask the child to answer or demonstrate:

1. “What does ice become when it gets warm?”
2. “What can hot water make?”
3. “How does oobleck feel when you push it quickly?”
4. “What happens when you move oobleck slowly?”
5. “What was your guess, and what did you observe?”

Accept spoken answers, gestures, drawings, demonstrations, or home-language responses.

Differentiation and Adaptations

For a Child Who Needs More Support

• Use only the words hard, wet, runny, hot, cold, and gooey at first.
• Offer two choices: “Did the ice become water or a rock?”
• Use picture or object cards for solid, liquid, and gas.
• Let the child observe without touching the oobleck.
• Repeat the same test several times and model the answer.

For a Child Ready for More

• Ask what might happen if there is more water or more cornstarch.
• Test whether a slow push and a fast push feel different.
• Invite the child to create a simple prediction chart with “I think” and “I saw.”
• Ask the child to find examples of solids, liquids, and gases around the home.
• Introduce the idea that heating and cooling can change matter back and forth.

Conclusion: Closure and Recap

Gather the child’s drawings or observations and say:

“Today we learned that matter can be a solid, liquid, or gas. Ice is a solid. Heat melts ice into liquid water. Very hot water can become water vapor, a gas. We also discovered that oobleck can feel hard when we push it quickly and flow like a liquid when we move it slowly.”

Ask the child:

• “What was your favorite thing to test?”
• “What surprised you?”
• “What is one thing you learned about matter?”

Finish with the child’s choice of a recap: draw the three states, act them out with body movements, or explain the oobleck experiment to someone else.

Optional Follow-Up

Place a small cup of water in the freezer and another cup in a warm area. Check both later and ask, “What changed? What helped it change?” Record the child’s prediction and observation using words or drawings.