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Science Experiments for Kids: Bottle Balloon Blow-Up

Observing Air Pressure

Science Experiments for Kids: Bottle Balloon Blow-Up

If your child jumps for joy at the thought of blowing things up, she will really enjoy the Bottle Balloon Blow-Up experiments. Though her excitement may die down temporarily when she realizes the only thing getting blown up is the balloon, it will be quickly reignited when she realizes that she can blow up balloons using various forces, none of which include forcing air from her lungs into the balloon. These experiments work best with latex balloons. However, before you begin, make sure none of your participants have latex allergies.

Skills Being Practiced

• Scientific inquiry
• Observation of the power of carbon dioxide gas
• Observation of the power of air pressure

Baking Soda Balloon Blow-Up Experiment

This experiment demonstrates the power of the chemical reaction created by combining baking soda and vinegar. It's powerful enough to blow up a balloon!

What You Need

• Empty water bottle
• Medium-sized balloon
• Funnel
• Vinegar
• Baking soda

Create a Hypothesis

Ask your child to predict what will happen when you combine baking soda and vinegar in a bottle. If she's ever seen a science-fair volcano, it's a good time to remind her that these are the same ingredients used in the volcano. Ask her to predict what will happen if you combine the same ingredients, but cover the top of the bottle with a balloon.

How to Play

1. Fill a clean, empty water bottle about one-third full with vinegar.
2. Place a funnel in the neck of the balloon, and hold onto it as your child pours in enough baking soda to fill the balloon about halfway.
3. Slip the funnel out of the neck of the balloon. Ask your child to hold the portion of the balloon with the baking soda in it to the side and downward as you stretch the neck of the balloon up over the neck of the bottle, being careful to not let any of the baking soda slip into the bottle. Make sure it is secure.
4. Help your child slowly lift the balloon over the bottle, and let the baking soda pour inside.
5. Ask your child to move aside. Have her listen and watch the bottle carefully. As you begin to hear the fizzing and crackling noise the baking soda and vinegar solution makes, hold tight to the neck of the balloon.
6. Watch as the balloon begins to inflate!

What's Going On

When the baking soda and vinegar are combined, the acetic acid in the vinegar breaks down the chemical composition of the baking soda (calcium carbonate). The carbon combines with some of the oxygen in the bottle to create carbon dioxide gas, which then rises and inflates the balloon.

Balloon in a Bottle Experiment

This experiment demonstrates that changing the air pressure inside a bottle with a little heat can make enough of a change to completely change the position of a balloon on the top of the bottle. This experiment requires precise timing and moves very quickly, so it's more suited for your child to be an observer, not an active participant. In order to help him feel more involved, you can designate him as the "official experiment recorder." Give him your cell phone or video camera to film the experiment as you do it.

What You Need

• Large glass jar (like a pickle jar)
• Balloon
• Water
• Tissue, or half a piece of paper towel
• Tongs
• Matches

How to Play 1. Place the neck of the balloon over the neck of a faucet. Turn the water on low and fill the balloon with just enough water so that it is a little too big to fit through the mouth of the jar. Tie off the neck of the balloon.
2. Grasp the piece of paper towel or tissue with a pair of tongs, and light it on fire. Drop it into the jar.
3. Very quickly, put the water balloon on the top of the jar, and watch what happens. The balloon will dance, and then be sucked right into the jar.

What's Going On At the beginning of the experiment, the air pressure inside and outside the jar is the same, but as the paper burns, it heats up the air inside the jar. The heated air expands, taking up more room, but the balloon is impeding the air's escape route. As the heated air pushes around the balloon to get out of the jar, the balloon "dances" out of the way. Once the fire goes out, the air in the jar cools, but since the water balloon is blocking the opening, no new air can get into the jar. That means the air pressure in the jar is lower than that of the pressure outside the jar. The outside air pressure exerts force on the balloon, pushing it into the jar.