We have built over 100 different science museum exhibits, mostly for the Cambridge Science Centre. These have included electrical generators, ball runs, stick insect cages, logic blocks and dissected household items.

We think that 95% of the time a small exhibit can teach and fascinate your visitors just as much as a large exhibit. Plus they have the advantage of being much cheaper, and you can get 2-3 times as many in the same space, allowing your visitors to explore more science, and making it more likely they will find something that inspires them.

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.
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.
This is a wonderful way to feel the conservation of energy. Turn the handle and switch on lights, and as you use more energy, turning the handle gets harder.
A ball or marble run is a good exhibit, but if you add a way of lifting the balls back up to the top again you get something great.
Build your own machine with gears, pulleys, cams, and other mechanical devices.
A stick that will display the current passing through a circuit made of a group of people as a flow of lights.
Interrupt a laser beam and you can produce clicks, pull a piece of mesh or patterned fabric across it, and you can make notes, play tunes, or even produce speech.
The boom-whacker or pipes of pan exhibit is an old favorite. Tune a series of pipes to different notes and the musical visitor hits the tubes to play a tune. We have added a tune guide to make it easier to use.
Complete circuits using your body and see the currents flowing through the exhibit.
The classic blower which makes a ball float stably in the air almost as if by magic.