Science -- Your Future, Scotland's Future
SCI-FUN Roadshow Exhibits -- Infinity Box
SCI-FUN Roadshow Exhibits -- Infinity Box
In this exhibit you learn about how we can use multiple mirrors to give the illusion of infinity.

We use mirrors in so many ways in our lives. As well as using mirrors to check our own appearance, we can also use them to see what's going on around us.

Mirrors in cars keep us safe on the road by allowing us to see what's coming up behind us. Curved mirrors on sharp bends in the road let us see what's coming around the corner.

Multiple mirrors can be used to make periscopes, so that we can see from a different angle. For example a submarine uses a periscope to see the surface of the water.

The Infinity Box uses a one-way mirror, which is see-through on one side, and partially reflective on the other. If a one-way mirror is lit on one side, but not the other, you can see through the mirror from the dark side, but not from the lit side.

One-way mirrors are made from glass with a thin layer of metal. The metal used is usually aluminium. This metal gives a reflective surface, but lets some light through because of how thin it is.

These kinds of mirrors can be used in various kinds of tricks. Pepper's Ghosts are illusions created using one-way mirrors that are often used in Haunted House fairground rides. A "ghost" is put behind a one-way mirror. When the "ghost" is lit up, it is visible, when it is not, the mirror reflects back the rest of the room. This way, the "ghost" can be made to appear and disappear.

1 Mirrors in cars allow us to see what's coming up ________ us.
2 What can we use to see round sharp bends?
3 What do submarines use periscopes for?
4 If a one-way mirror is lit on one side but not the other, which way can you see through?
5 Where might you see a Pepper's Ghost?
6 Can you think of any other uses for one-way mirrors?

1 Can you make your own Infinity Box? You'll need a lens from a pair of reflective sunglasses and a mirror. Hold the sunglass lens with the reflective side facing the mirror. Experiment with putting different objects between the lens and the mirror, and changing the distance between the lens and the mirror.
2 Can babies recognise themselves in mirrors? Put some kind of dirt of the face of a sleeping baby (check with the parents first). When it wakes up, put it in front of a mirror. If the baby recognises itself, it will realise it has dirt on its face and touch it. If it thinks that the baby in the mirror is someone else, it might try to communicate with the mirror, or just ignore it. Try it again and again as the baby gets older, to see when the baby starts recognising itself (usually around 18 months old).