A lamp beam on a curved panel

Open to everyone until Thursday, October 1

To keep it, print it while it is open.

A lamp shines onto a curved surface. Where the light lands straight on, all its energy is packed into a tiny spot; where it lands at a slant, the same energy is spread over a wide patch.

In the picture

The small bright circle on the panel: light arriving straight on, packed into a small area
The wide pale band on the panel: the same light arriving at a slant, spread over a larger area
The glowing bulb of the lamp: the source that sends out the beam

Examples

The midday sun feels hotter than the sun in the late afternoon.
A torch held straight at your hand makes a small hot circle, but tilted it makes a bigger, weaker patch.

Key takeaways

Straight-on light packs its energy into a small area, so that spot gets warmer.
Slanted light spreads the same energy over a wider area, so each part gets less warmth.