What happens when you mix vinegar, baking soda and dish detergent in a plastic soda bottle? 

Do the Foaming Bottle Model experiment and find out.

About the experiment:  you will generate carbon dioxide gas to propel the dish detergent out of the bottle.  This model works on the principle that a gas will move from an area of high pressure to an area of low pressure.

or try The Gelatin Party experiment with some friends

About the experiment:  this experiment demonstrates gas expansion and volumetric changes of a product (whipped cream) under pressure.  And, best of all, you get to eat your experiment when you're done!