Light

Spectrometer and spectrum tubes

Different lights produce light in different ways, and so produce very different spectra. With a spectroscope you can investigate the hidden depths of light.

 

We have built these as outreach kit and exhibits, with different light sources to look at including a variety of white light sources, a selection of gas discharge tubes and looking at fluorescent materials.

Telescope with swappable lenses

You can swap lenses by rotating two wheels while seeing exactly what is going on inside. This helps you understand what is going on in the telescope.  By swapping the lenses you can change the zoom from 0.2x to 10x twisting the focus knob will move the objective lenses and focus the telescope.

The telescope can be panned, and tilted. The tilt is achived by a sliding piviot, so it rotates around a point above the centre of mass, so it naturally sits approximately level.

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.

Wheels with teeth or slots in them make a wonderful noise.

Infinity Mirror

One is two mirrors set at an angle to one another creating images curving away to infinity.

The second one is two mirrors facing each other one is only partially silvered so you can see in from the outside.

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.

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.

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