Why not recycle a few of those scratched DVDs, or Cd's you pulled out of a cereal box, and make a great science toy at the same time?
For this project you need:
- a CD or DVD that can be sacrificed to the project
- the top off of a water bottle, pancake syrup, or dish soap bottle (the kind that you pull up to open, and push down to close)
- a balloon (the bigger the better, but any size will do in a pinch)
- hot glue, or crazy glue
The steps for construction are extremely simple.
Glue the bottle top over the hole of the CD. It is important to make an airtight seal between the CD, and the edge of the bottle top, but do not block the hole in the CD.
After the glue dries, place the balloon on the bottle top, covering the entire thing.
With the bottle top open, blow up the balloon by blowing through the CD. When the balloon is full of air, close the bottle top (this can be a little tricky, but it is possible). Place the hovercraft on a smooth surface, and open the bottle top.
A little push demonstrates Newton's first law of motion (see http://gbhsweb.glenbrook225.org/gbs/science/phys/class/newtlaws/u2l1a.html for a kid friendly explanation of Newton's laws, or have them watch The Magic School Bus Plays Ball).
It's great to be a homeschooler.