Smash Pumpkins DIY

This Halloween pumpkin balloon experiment for kids hides baking soda and a sealed bag of orange vinegar inside a clear balloon, then puffs it up into a jack-o’-lantern.

 

Materials you’ll need

• clear balloon
• marker
• sheet of paper (to fold into a funnel)
• baking soda
• vinegar
• orange food coloring
• small dish
• small clear plastic bag
• twist tie
• green paper
• scissors

 

Step-by-step tutorial

Step 1: Use a marker to draw a jack-o’-lantern face and curved pumpkin lines on a clear balloon.

Step 2: Fold a sheet of paper into a narrow funnel and slide it into the neck of the balloon. Pour 1 tablespoon of baking soda through the funnel into the balloon.

Step 3: Pour some vinegar into a small dish and add a few drops of orange food coloring.

Step 4: Put 2 tablespoons of the orange vinegar into a small plastic bag. Twist the top closed and seal it tightly with a twist tie.

Step 5: Stretch open the balloon’s neck and push the vinegar bag inside. Tie the balloon closed. A grown-up can help with the stretching and tying, and grown-ups should supervise kids under 8 whenever balloons are out.

Step 6: Set the balloon on a table and smash it with your hand to burst the bag inside. Watch your pumpkin grow!

Step 7: Fold a piece of green paper in half and cut out a leaf shape with a small hole at the fold. Slip the leaves over the balloon’s knot for a stem. If the balloon pops, pick up every piece and throw them away.

Learn more

Your pumpkin grows thanks to an acid-base reaction. Vinegar is an acid and baking soda is a base, so when you smash the bag and they mix, they react and make carbon dioxide gas, plus a little water and sodium acetate, a type of salt. The tied balloon traps all that gas, so it pushes out on the stretchy walls and puffs your pumpkin up.

If you had a blast with this chemistry experiment, Bottle Rocket Blaster takes gas-making reactions further with a hydraulic detonator and launch pad kids build to send a bottle rocket flying.