1. Spin The STEM Top under a household light source to see the effects of the 60hz electricity on the top.  As the top slows down, you should be able to see the optical illusion of the outer indentations appearing to slow down and then reverse direction and speed up again.

Not all electric light sources produce the effect.  If you’re not seeing the effect try another light source.

This effect happens because the electric light is actually strobing 60 times per second, which is imperceptible to the naked eye.  But when the indentations rotate at the right sync speed, the strobing from the light source ‘freeze’ the indentations in place and they appear to stand still for a moment.  As the sync speed slows, the indentations appear to reverse direction increasingly faster.

2. Spin The STEM Top with the printed graphic inserts and watch the interesting effects as the top spins and slows down.

DISCUSSION TOPIC: Why do different parts of the graphic seem to rotate clockwise while other parts are rotating counter-clockwise?

Feel free to submit your observations in the comments section below.

3. Use the dry-erase inserts to create your own patterns and experiment with different designs.

Here are some ideas to get you started: