All you need is:
- some baking soda
- a sink
- bubble soap, and blowers
- and a child, or two (optional)
Pour about 1/2 cup of baking soda into the sink, or into a pie plate placed in the sink.
Add vinegar, to create the fizzy foam, of homemade volcano fame.
When the fizz begins to die down, blow a few bubbles over the sink, and watch them hover, mysteriously, in mid-air. It's pretty cool.
Of course, what is happening, is the carbon dioxide gas, produced by the baking soda/vinegar reaction, is staying at the bottom of the sink, because carbon dioxide is heavier than air. The invisible gas, holds up the bubbles, as they start to fall into the sink. Eventually the gas will dissipate, and the bubbles will fall, as usual.
You can do something similar with dry ice, but baking soda, and vinegar are common kitchen items, and safer for little hands.
It's great to be a homeschooler.