Science Activity: Balloon Blower-Upper

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Would your friends be amazed if you showed them a balloon that could blow itself up? In this activity, you'll discover how to make an automatic balloon blower-upper. When you show it to your friends, they'll wonder how it works!

1. Get Ready

Clean, empty, plastic 2 liter soda bottle
Round balloon that will inflate to at least 9 inches (about 23 centimeters) across
1 cup white vinegar
2 tablespoons baking soda
Enough aluminum foil to wrap around bottle
Funnel
Plastic bowl or tray

2. Do and Wonder

Place the bottle upright in the plastic bowl or tray. Add the vinegar to the bottle.

Inflate and deflate the balloon a few times until it becomes easy to blow up.

Using the funnel, put the baking soda in the balloon. Put the open end of the balloon over the top of the soda bottle; the part containing the baking soda should be hanging down along the neck of the bottle. Be careful not to spill any of the baking soda into the bottle. What do you predict will happen if you pull the balloon up and spill the baking soda into the vinegar?

Pull the balloon up, and then step away from it. Write down your observations.

To show your invention to your friends, first wrap the bottle in foil so no one will be able to see the vinegar and baking soda reacting.

3. Think and Write

Write a short paragraph that answers these questions: What changes did you observe in the bottle? What do you think caused the balloon to blow up? How could you make the reaction go faster or slower?

Explanation

Baking soda reacts with vinegar to produce carbon dioxide gas and other compounds. The gas increases the pressure inside the bottle, which causes the balloon to inflate.

Safety Hint

Be sure to place the bottle in the bowl or tray in order to catch any liquid that might squirt out.