Step-by-step tutorial
Step 1
Take the glowstick into a dark room. Move it back and forth slowly. What do you see?
Step 2
Now whip it back and forth as fast as you can. What do you see this time?
Step 3
Try moving your glowstick in other ways and discover what shapes you can make.
Fact
When you moved the glowstick back and forth really fast, it started to look like a solid shape made of light. But that shape isn’t actually there — the glowstick is still just a glowstick.
Your eyes hold onto images for a split second . . . even when those images are no longer there. So when the glowstick is moving quickly, you see a whole bunch of glowstick images all at once. Then your brain blends those images together into the illusion of a glowfan!
