Polarised Light Stress Patterns
Crossed polarisers with a space between them, big enough to place various objects. These can be twisted, stretched, crumpled, etc. All show very pretty colours in the polarised light, but are colourless and transparent in normal lighting.
An excellent test bed for examining how light travels through a variety of prisms. Reflection, refraction, total internal reflection and interactions between prisms can be seen . The light used is an intense single beam of red laser light.
Lissajous Figures 2
This is a “3 Axis” Spirograph!
Similar to the exhibit seen in the fourth room, this has three spinning mirrors, producing very complex patterns, some having an intricate "3D" appearance.
A cabinet contains a variety of samples. The user turns a control to switch between "normal" illumination and ultra-violet illumination. The effect of the u.v. illumination is to make some of the samples glow or change their colour. Some surprising effects can be seen. One is the length of acrylic ("Perspex") which is of course transparent to visible light, but is opaque to u.v., casting a shadow on the (otherwise glowing) sample beneath it.