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.

Rods made of different materials with the same ring magnet being dropped around them. The better the conductivity of the rod, the slower the magnet drops.
Complete circuits using your body and see the currents flowing through the exhibit.
If you put a current through a wire near a magnet, it jumps sideways. The basis for all electromagnets, and therefore motors, solenoids etc.
As a magnet moves near a coil of wire it generates a voltage, if it is moving fast enough it can produce some light.
Almost all of our electricity is generated using coils and magnets. Have a go yourself with this classic exhibit.
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.