8 Really Fun Heat Experiments for Kids | Easy Science Activities by Age

Heat is everywhere—it warms our homes, cooks our food, and even powers engines. But for kids, heat can be an abstract concept.

Why does ice melt?

Why do metal objects feel hotter than wooden ones?

Why does a balloon inflate when placed in warm air?

The best way to answer these questions is through hands-on experiments.

This guide offers age-appropriate heat experiments that will turn science into an adventure. Each activity is designed to be safe, engaging, and packed with “wow” moments that help kids see and feel heat in action.

🔥 Experiments for Ages 3-5: Discovering Heat Through Play

At this age, kids are curious. So they need simple, hands-on experiences to understand abstract ideas.

These two experiments introduce heat in a fun, visual way.

1. Color-Changing Spoon Experiment

What it teaches: Some materials change when they absorb heat.

🔬 What You Need:

• A heat-sensitive color-changing spoon (or a regular metal spoon)
• A cup of warm water
• A cup of cold water

🔍 How to Do It:

1. Let your child hold the spoon at room temperature and describe its color.
2. Dip the spoon in cold water—does anything change?
3. Now dip it in warm water and watch the magic!

💡 Why It Works: Some spoons are coated with a heat-sensitive material that changes color when warmed. Even with a regular spoon, kids can feel how it warms up in hot water and cools down in cold water.

2. Ice vs. Warm Water Experiment

What it teaches: Heat moves from warm objects to cold ones.

🔬 What You Need:

• Two small bowls
• Ice cubes
• Warm water

🔍 How to Do It:

1. Place one ice cube in an empty bowl and another in a bowl of warm water.
2. Ask your child to guess which will melt faster.
3. Watch as the ice in warm water melts almost instantly!

💡 Why It Works: Heat always moves from hot to cold. The warm water transfers its heat to the ice cube, making it melt much faster than in the air.

🔥 Experiments for Ages 6-8: Exploring Heat and Movement

Kids at this age start asking “why” and “how” more often. These experiments help them see heat’s effects on air and materials.

3. Expanding Balloon Experiment

What it teaches: Warm air takes up more space than cold air.

🔬 What You Need:

• A balloon
• An empty plastic bottle
• A bowl of warm water
• A bowl of cold water

🔍 How to Do It:

1. Stretch a balloon over the mouth of the plastic bottle.
2. Place the bottle in warm water—watch the balloon slowly inflate!
3. Move the bottle to cold water, and the balloon deflates.

💡 Why It Works: When air heats up, its molecules move faster and spread out, causing the balloon to expand. Cooling the air makes it contract.

4. Melting Chocolate Race

What it teaches: Some materials conduct heat better than others.

🔬 What You Need:

• Chocolate pieces
• A metal spoon
• A wooden spoon
• A plastic spoon
• A warm, sunny spot (or warm water)

🔍 How to Do It:

1. Place a chocolate piece on each spoon.
2. Leave them in the sun or warm them over warm water.
3. Observe which chocolate melts the fastest.

💡 Why It Works: Metal conducts heat faster than wood and plastic, transferring warmth to the chocolate more quickly.

🔥 Experiments for Ages 9-12: Science Gets More Exciting

Older kids can start exploring air pressure, heat measurement, and real-world science concepts.

5. Rising Water Magic Experiment

What it teaches: Heated air expands, and cooling air contracts, creating suction.

🔬 What You Need:

• A small candle
• A plate
• A glass
• Water

🔍 How to Do It:

1. Pour water onto the plate.
2. Light the candle and place it in the center.
3. Cover the candle with the glass and watch the water rise!

💡 Why It Works: The flame heats the air inside the glass. When the flame goes out, the air cools and contracts, pulling water up.

6. DIY Thermometer Experiment

What it teaches: How a thermometer works.

🔬 What You Need:

• A clear plastic bottle
• Rubbing alcohol
• Water
• A straw
• Food coloring

🔍 How to Do It:

1. Mix equal parts alcohol and water, adding food coloring.
2. Insert a straw into the bottle and seal the opening with clay.
3. Warm your hands around the bottle and watch the liquid rise!

💡 Why It Works: Liquids expand when heated, which is how thermometers measure temperature! (We have an article on how to make your own weather station here.)

🔥 Experiments for Ages 13-16: Advanced Heat Concepts

Teens can experiment with convection currents and thermal expansion, essential in physics and engineering.

7. Convection Currents in Water

What it teaches: How heat moves in liquids and gases.

🔬 What You Need:

• A large clear container
• Cold water (blue food coloring)
• Warm water (red food coloring)

🔍 How to Do It:

1. Fill the container with cold water.
2. Slowly pour warm, red-colored water into one side.
3. Watch the warm water rise while cold water sinks!

💡 Why It Works: Warm fluids rise while cold fluids sink, driving currents in oceans and the atmosphere.

8. Bimetallic Strip Bending Experiment

What it teaches: Different metals expand at different rates.

🔬 What You Need:

• A bimetallic strip (or two different metal strips joined together)
• A candle or lighter

🔍 How to Do It:

1. Hold the strip with tweezers over the flame.
2. Watch how it bends as it heats up!

💡 Why It Works: Metals expand when heated, but some expand more than others, causing the strip to bend.

🚀 Science is even more fun when kids experience it firsthand! Try these experiments and turn your home into a mini science lab! 🚀