Science Demonstrations

We have been building a wide variety of science demonstrations since about 2000, originally for CHaOS (Cambridge Hands On Science), and our own shows but more recently for Lab in a Lorry, The Naked Scientists shows, the Cambridge Science Centre, the RI christmas lectures and others.
Having done a huge amount of loading experiments in and out of vans we have now become obsessed with making experiments pack as efficiently as possible, preferably into a standard box or if that is not possible, then as a clean flat object which will pack nicely.

Most space rockets are launched from the equator. Why is this?
A pair of trolleys with very low friction, so you can throw fuel one way and the trolley will go in the other - a rocket.
Vacuum bazookas are a classic demo, which can be used to think about pressure and momentum. We went slightly further and have produced various repeating versions.
The ancient Indonesians invented a very neat way of creating a fire: they took a cylinder, added a little tinder, then used a piston to compress the air around it very rapidly, heating it up enough for ignition.
This cloud chamber allows you to see tracks from individual alpha and beta particles.
Sodium lights are fascinating because they are pretty much monochromatic: colour disappears when you look at an object under them, because if you illuminate an object with just one colour it can only reflect back that one colour. You can also use it to produce a spooky dark flame effect.
A mass spectrometer separates ions by their mass. This an analogy using ball bearings and a magnet.
The fire tornado is one of the most beautiful science demos, a combination of hot air floating, and the conservation of angular momentum produce a beautiful spinning column of flame.
One favorite experiment is the Gherkinator, essentially electrocuting a gherkin to produce sparks which glow due to the salt they are soaked in.