manual

41
spiral disk
Things on the Move card
yellow pin
You need:
Read CAUTION on the next page
before trying this experiment.
How to do it:
Insert the pin in the center of the disk.
1) On a very smooth surface, spin the disk
in one direction and observe the
movement for about 15 seconds.
2) Quickly move your gaze to the card
with the clouds: everything is moving!
3) Now, spin the disk in the opposite
direction, observe for 15 seconds,
and look at the image again. Notice
it’s now moving in the opposite direction.