Washington County 4-H: STEM at Home

---

1. Balloon-Powered Car 🚗

STEM Areas:

Engineering, Physics

Materials:

• 1 balloon
• 1 drinking straw
• Tape
• Cardboard (for car body)
• 4 bottle caps or cardboard circles (wheels)
• 2 wooden skewers or pencils (axles)
• Scissors

Instructions:

1. Cut a rectangle from cardboard for the car base.
2. Attach two skewers underneath the cardboard to act as axles.
3. Attach bottle caps to the ends of the axles as wheels.
4. Tape a straw to the top of the car.
5. Stretch the balloon opening over one end of the straw and secure with tape.
6. Blow up the balloon through the straw.
7. Pinch the straw closed, place the car on the floor, and release.

Challenge:

Can you redesign your car to travel farther?

STEM Connection:

The air rushing out of the balloon pushes backward, causing the car to move forward.ite reaction.

Challenge Question

How can you change your car to make it travel farther without using a larger balloon?

Family Discussion Prompt

What parts of real cars help them move efficiently? How is a balloon-powered car similar to or different from a gas-powered or electric vehicle?

2. Homemade Lava Lamp 🌋

STEM Areas:

Chemistry

Materials:

• Clear plastic bottle or jar
• Vegetable oil
• Water
• Food coloring
• Alka-Seltzer tablet

Instructions:

1. Fill the bottle about ¾ full with vegetable oil.
2. Add water until the bottle is nearly full.
3. Add 5 to 10 drops of food coloring.
4. Wait for the food coloring to sink through the oil.
5. Break an Alka-Seltzer tablet into pieces.
6. Drop one piece into the bottle and watch.
7. Add more pieces as desired.

Challenge:

Try different amounts of water and oil. Does it change the effect?

STEM Connection:

Oil and water have different densities and do not mix. Gas bubbles carry colored water upward before it sinks back down.

Challenge Question

What do you think would happen if you used more water than oil? Would the lava lamp still work the same way?

Family Discussion Prompt

Can you think of other liquids that don’t mix together? Why do some liquids stay separated while others blend?

3. Marshmallow Toothpick Structures 🏗️

STEM Areas:

Engineering, Math

Materials:

• Toothpicks
• Mini marshmallows or gumdrops

Instructions:

1. Use marshmallows as joints.
2. Connect toothpicks to create shapes.
3. Start with triangles and squares.
4. Build a tower, bridge, or house.
5. Test how tall or strong your structure can be.

Challenge:

Can your tower stand for 30 seconds without support?

STEM Connection:

Engineers use shapes like triangles because they provide strength and stability.

Challenge Question

Can you build a structure that is both tall and strong enough to support a small toy?

Family Discussion Prompt

Why do engineers use certain shapes, like triangles, in bridges and buildings? Which shapes seemed strongest during your experiment?

4. Walking Water Rainbow 🌈

STEM Areas:

Chemistry, Earth Science

Materials:

• 6 clear cups
• Water
• Paper towels
• Red, yellow, and blue food coloring

Instructions:

1. Arrange six cups in a row.
2. Fill cups 1, 3, and 5 halfway with water.
3. Add red coloring to Cup 1, yellow to Cup 3, and blue to Cup 5.
4. Leave Cups 2, 4, and 6 empty.
5. Fold paper towels into strips and place one end in a full cup and the other in an empty cup.
6. Wait several hours and observe.

Challenge:

Predict what colors will appear in the empty cups.

STEM Connection:

Water moves through paper towels by capillary action, the same process plants use to move water.

Challenge Question

Which color combinations do you think will create the most surprising new colors in the empty cups?

Family Discussion Prompt

How do plants move water from their roots to their leaves without using pumps?

5. Egg Drop Challenge 🥚

STEM Areas:

Engineering, Physics

Materials:

• Raw egg
• Tape
• Straws
• Paper
• Cotton balls
• Recyclable materials

Instructions:

1. Design a container to protect your egg.
2. Use available materials to create cushioning.
3. Place the egg inside.
4. Drop it from a safe height.
5. Check if the egg survived.
6. Redesign and test again if needed.

Challenge:

Can your egg survive a drop from a second-story height?

STEM Connection:

Engineers design products and vehicles to absorb impact and protect what’s inside.

Challenge Question

If you could add only one more material to your design, what would you choose and why?

Family Discussion Prompt

How do engineers protect people and valuable items from crashes, falls, or impacts in everyday life?

6. Baking Soda Rocket 🚀

STEM Areas:

Chemistry, Physics

Materials:

• Film canister or small plastic container with tight lid
• 1 tablespoon baking soda
• 2 tablespoons vinegar

Instructions:

1. Pour vinegar into the container.
2. Add baking soda.
3. Quickly snap on the lid.
4. Place the container upside down on a flat outdoor surface.
5. Step back and wait for launch.

Challenge:

Experiment with different amounts of baking soda and vinegar.

STEM Connection:

The chemical reaction creates carbon dioxide gas. Pressure builds until the lid pops off and launches the rocket.

Safety Note:

Always perform outdoors and wear safety glasses.

Challenge Question

How can you make your rocket launch higher while using the same materials?

Family Discussion Prompt

What are some examples of gases creating force in real-world applications, such as airplanes, rockets, or car engines?

Adult supervision recommended.

7. DIY Water Filter 💧

STEM Areas:

Environmental Science, Engineering

Materials:

• Plastic bottle
• Coffee filter
• Cotton balls
• Sand
• Small rocks or gravel
• Dirty water

Instructions:

1. Cut the bottle in half.
2. Turn the top upside down into the bottom half.
3. Place a coffee filter in the neck.
4. Add cotton balls.
5. Layer sand and gravel on top.
6. Slowly pour dirty water through the filter.
7. Observe the water collected below.

Challenge:

Which material removes the most dirt?

STEM Connection:

Water treatment plants use multiple filtration stages to clean water.

Challenge Question

Which filtering material removed the most dirt, and how could you improve your design?

Family Discussion Prompt

Why is access to clean water important? What steps do communities take to make drinking water safe?

Important:

Filtered water is not safe to drink.

8. Paper Helicopters ✈️

STEM Areas:

Physics, Engineering

Materials:

• Paper
• Scissors
• Paper clips

Instructions:

1. Cut a strip of paper about 1 inch by 8 inches.
2. Cut halfway down the center from the top.
3. Fold the cut sections in opposite directions to create blades.
4. Fold the lower section as a body.
5. Attach a paper clip for weight.
6. Drop from a safe height.

Challenge:

Try longer blades or heavier paper clips and compare results.

STEM Connection:

The spinning blades create drag, slowing the fall.

Challenge Question

How does changing the size of the blades affect how quickly the helicopter falls?

Family Discussion Prompt

How do helicopters, airplanes, and parachutes use air resistance in different ways?

9. Solar Oven 🍫

STEM Areas:

Energy Science

Materials:

• Pizza box
• Aluminum foil
• Plastic wrap
• Black construction paper
• Tape
• Marshmallows or chocolate

Instructions:

1. Cut a flap in the pizza box lid.
2. Cover the underside of the flap with aluminum foil.
3. Cover the opening with plastic wrap.
4. Line the bottom of the box with black paper.
5. Place food inside.
6. Angle the foil flap to reflect sunlight into the box.
7. Wait and observe.

Challenge:

Measure how long it takes different foods to melt.

STEM Connection:

Solar ovens use sunlight as renewable energy to produce heat.

Challenge Question

What changes could you make to trap more heat and cook food faster?

Family Discussion Prompt

What are some advantages and challenges of using solar energy instead of electricity or fossil fuels?

10. Catapult Challenge 🎯

STEM Areas:

Engineering, Physics

Materials:

• 8 popsicle sticks
• Rubber bands
• Plastic spoon

Instructions:

1. Stack six sticks together and secure with rubber bands.
2. Attach one stick above and one below the stack.
3. Insert the stack between the top and bottom sticks to form a lever.
4. Attach a spoon to the top stick with a rubber band.
5. Place a marshmallow in the spoon.
6. Press down and launch.

Challenge:

Create a target and score points.

STEM Connection:

The catapult stores potential energy, which becomes kinetic energy when released.

Challenge Question

Which adjustment has the biggest effect on how far your catapult launches: spoon position, arm length, or launch angle?

Family Discussion Prompt

Where do we see levers used in everyday life? How do simple machines help make work easier?

Bonus STEM Reflection Questions

These can be used with any activity:

🔍 Before You Start

• What do you think will happen?
• Why do you think that?

🧪 During the Activity

• What changes do you notice?
• What surprised you?

💡 After the Activity

• What worked well?
• What would you change next time?
• What did you learn?
• How does this relate to something in the real world?

---

---