Combine some simple electric circuit building with craftwork. High intensity LEDs are small sources of light so they make sharp shadows. Build the circuit above and place the LED in a supporting structure such as that on the left. In dark conditions use the LED to make a shadow of a pupil’s head on a large sheet of paper. Draw round the shadow. Repeat for all the members of your club to create a rogues’ gallery.

Draw coloured pictures that will change when they are viewed through different coloured filters. A comparatively complicated example is shown below. If you do not have filters, try saving coloured sweet wrappers. The key is to have coloured pencils (better than felt-tips) that more or less match the filters or wrappers.

You can make an electromagnet by winding enamelled (or plastic-coated) copper wire round an iron rod or large nail.
It can be powered from two rechargeable cells, which gives the 2.4V shown. Other battery arrangements could be used instead.

You will need reasonably thin wire so that you can wind it round many times. The best number depends on your battery and the thickness of your wire, so some experimentation will be needed.

Beware of the fact that the wire can become very hot and plastic wire might melt in that case. Check carefully when you test your device.

The strength of your magnet might be tested by finding out how many paper clips it will hold up.

N.B. If you are using enamelled wire, you will need to scrape away the enamel at the ends where you wish to make a connection to the battery.

You will need a plastic cotton reel, a selection of elastic bands, a short length of wire, and some suitable pieces of wooden dowel (see pictures following).

When you remove the labels from the cotton reel you will probably find a round hole through the middle with other holes in segments round it. Push a short piece of dowel into one of these outer holes.

Wrap an elastic band round the piece of dowel and use a bent wire to pull the elastic band through the centre hole. Fit a longer piece of dowel through the elastic band.

Twist the elastic band by winding the long piece of dowel. Place the device on a flat surface and, with a bit of luck, it will roll along.

Problems: If the elastic band is too thin it will just break. If it is too tough you are likely to have ‘wheel spin’ when the cotton wheel will just spin round instead of rolling along. You will need to experiment with a variety of elastic bands.