Luminous wall

How does the exhibit work?

Press the button and stand against the wall. A bright flash appears all over the wall. You hear a beep. Your shadow is now on the wall. You can take the black light pen to draw on the wall.

What is the science behind it?

If you press the button, the light shines everywhere on the wall, except on the spot where you stand. You will see the shadow of yourself on a luminous wall.

This is because this wall absorbs light. When it gets dark again, it continues to emit light for a while. Except on the spot where there was no light, your shadow. Use a light pen to add a moustache, wings, crown, etc. to your shadow.

We also call this wall phosphorescent. Please note that this is not the same as fluorescent. You will notice the difference when you turn off the light. Fluorescent material stops emitting light immediately, think of a fluorescent jacket. Phosphorescent material, on the other hand, continues to emit light for several seconds to minutes.

Phosphorescence in glow-in-the-dark stars

Do you have luminous stars in your bedroom? They are also phosphorescent. During the day they absorb light, and when it gets dark, they continue to give off light for a while.