I’ll demonstrate how to build a simple magnetic optical mount for a cat toy (laser pointer). Though it is simple—that is, there aren’t any fine tuning mechanisms one would find on an optical bench—it is, nonetheless, inexpensive and flexible enough to use for simple optical experiments such as demonstrating the Tyndall effect, .

I used a magnetic chip clip to clamp the laser pointer switch (a press switch) in the on position and attach the laser pointer to the Erector set mount. Unfortunately, there are plastic grips on the chip clip that interfere with the smooth rotation of the chip clip against the Erector set strip. So, I added a neodymium magnet from a magnetic keychain that I took apart and the keychain magnet lets me smoothly rotate the chip clip.

Parts Needed:

Magnetic chip clip
(Optional) neodymium magnet

Erector Set Parts:

1 Strip, 1 1/2”, 15 hole
1 Base plate, seven hole by five hole
2 Triangle brackets
4 Small bolts
2 Medium bolts
6 Nuts
12 washers
1 Spanner
1 Hex wrench

Here’s a demonstration of the Tyndall Effect with one milliliter of milk in 250 milliliters of tap water. Follow me on Twitter @SteveSchuler20