HOW COOL IS THIS!!

Instead of using Helium gas to fill the balloons you could use a mix of vinegar with baking soda.

You need:1 plastic bottleBalloons1 teaspoon of baking soda3 tablespoon of vinegar

How to make it:Add the baking soda in a balloon using a small funnel. Add vinegar in the bottle. Place the balloon on the bottle and then lift up the balloon letting the powder reach the vinegar. You will see some bubbles forming and the release of dioxide carbon gas.

Vinegar is acid and when it finds the baking soda (sodium bicarbonate), the CO2 is formed.