How to make homemade science toys?

How to make homemade science toys?

My fave is a pinhole camera.
Get a cardboard box - any size - or make one...say a six inch cube
Remove one side...that is going to be the top.
Make a pinhole in one of the upright sides and you should see an upside down image Projected onto the opposite side (inside the box)
If the light is too strong and the image is not clear try covering the top and just peek under it.

You can also make another gadget. This time you get a piece of sturdy wire and bend it so it looks like a wavy line - maybe a foot long.
Then get another piece of sturdy wire and make it straight with a loop at the end.
Wire up both pieces to a battery and a doorbell.
You then have to try manouvering the loop round all the twists and turns along the wavy line without touching it.
If you touch it the bell rings because it completes the connection.
The person making the fewest rings is the winner !