Blackout

A retangular box with a sloped face and two cut out black areas.
A red and yellow exhibit table with an orange, white and purple information panel at the back, sits in front of two green and blue walls. On the table is a rectangular box with a sloped face and two square black areas.

Humans can only see an object if light is being reflected from that object.

How it works

Peer into a box, then open the lid to reveal the colour of the box inside, due to reflected light.

Things to try or ask around the exhibit

  • What colour is the box painted inside?
  • Does the colour change inside the box when light is allowed inside?

Background

Nothing has to leave your eyes for seeing to occur. Your eyes can only receive light.

When the box's lid is closed, the tiny amount of light inside the box is absorbed by the box’s lining or reflected back out through the hole, so it appears black to your eyes.

When you lift the lid and let in lots of light, the box’s red lining reflects MOST of the light back to your eye so it appears red. If ALL of the light was reflected, it would be a mirror.

Finding the science in your world

If you peer into a dark room, you are unable to distinguish shapes and colours until light is used to illuminate the room and it reflects off the room's objects, walls and ceiling and reaches your visual system.

Some coloured paints or surfaces are more effective at reflecting light. By selecting colours that tend to contrast more with their surroundings, or by selecting materials that are better at reflecting light (such as retroreflective materials), high visibility equipment can be created for safety on the road or within construction sites.