Light

Laser communication

This consists of a transmitter which converts an electical audio signal to a laser light signal and a receiver which does the opposite. This means you can send light across a room if you can aim the laser accurately enough.


If something gets in the way (like a planet) you can use a mirror to reflect the light around a corner, or use an optical fibre to bend the light around the surface. It makes a good analogy to how satellites and optical fibre communications work.

Laser cello

This consists of a laser pointing at a light sensor across a gap. The light sensor is connected to a speaker, so if you move an object like a piece of mesh across the gap it will block the light many times a second you produce sound.

You can experiment with moving different objects with different patterns of holes, such as sieves, fabrics, combs etc, at different speeds to see what sounds they make.

You can also make acetates with sound patterns printed onto them and produce more complex sounds. This is how sound was stored on film until digital audio was introduced.

Graphite filament

This is a classic, simple demo that is surprisingly hard to do, because it is hard to hold a very brittle, thin propelling pencil lead without it breaking.

This setup is machined with a groove between the two stainless steel pillars that is completely in line, so that there are no bending forces on the lead, so it reliably doesn't break.

Disappearing image - LCD monitor

This basically consists of a monitor and piece of polariser. However the monitor has had the outer piece of polariser scraped off. This means that all the light that gets through the rear polariser can always get through. But if you look through a polariser you can see the picture again. Rotating the polariser by 90 degrees will of course let through all the light which was previously blocked, so inverting the image.

This shows how a piece of physics can be used in something we use every day.

Heat sensitive plastic

This is a cheap simple exhibit and allows visitors to make a (tempory) mark on the exhibition. The plastic has a transition temperature and you may find that you need more than one version for summer and winter if the temperature of your gallery (and visitors) changes too much.

Additive Light mixing

This is the classic 3 circles of light exibit that you can mix to make other colours. All three lights have brightness controls, so visitors can change to colour of light to anything they like. The lights are also moveable, allowing more interaction.

Subtractive light mixing

If you are mixing light you add colours together, and if you get the right mixture it will look white. When you mix pigments you start with white light, and remove colours. So the primary colours instead of being one of red, green or blue, they subtract red, green or blue, leaving cyan, magneta, or yellow.

Colourblind Camera

It uses a camera and some software to simulate 3 different kinds of colourblindness.

Red green - by averaging the red and green channels to give a yellow channel (there are two subtley different forms from loosing the red or the green cone in the eye, but the actual sensitivity of the red and green cones are very similar)

Blue yellow - by loosing the blue cones

Pages