More ideas from Az
Here's a great experiment for collecting gas (and showing one of the signs of a chemical reaction).

Helium balloons without helium -- water & vinegar in bottle, baking soda in balloon

Need to fill balloons with helium? A DIY cheap way: vinegar and baking soda!

No helium needed to fill balloons for parties.just vinegar and baking soda! I NEED TO REMEMBER THIS! this is important since helium is not a renewable source and is in such short supply-kid science project