Show your kids the phenomenon of "afterimage" with this DIY little machine. All you need is:

- some iron or copper wire
- a straw
- a sheet or white thin cardboard
- colors

I took the idea of the turbine from a kids craft blog, and I really would like to thank the author but I can't find it back. I feel sorry for that... I added the colors disk to have a purpose for the movement.

Step 1: Get Your Metal Wire

I got mine from a dyer hanger. It has to be solid enough, but easy to cut and bend...

Step 2: Prepare the "blower"

Bend the wire, cut it, and strap the straw along it.

Step 3: Build the Turbine

Sorry the picture is of poor quality... I used 2 plastic bottle caps, put a small piece of straw in them, and added the thin cardboard turbine.

I'm afraid my grandson did put too much glue when building it, but it's working well though. So I won't complain...

Step 4: Check

Put the turbine on the axle. Blow through the straw. Does it turn? The blow should not arrive on the axle but in the middle of the blades. If necessary, bend the metal wire.

Step 5: Make the Disks

Prepare the disks with elementary colors. You can try different combinations, knowing yellow and blue will produce green, yellow and red will produce orange, etc.