The different teams make kits cars using different power sources. Team one uses battery power, Team 2 elastic bands, Team 3, water jet.
Cardboard boxes, plastic items, , elastic bands, tape, glue, rods for axels /for battery power, elastic bands (drive belt), an electric motor, batteries / for water jet a fizzy drinks bottle, a cork with an 8mm hole drilled in it, a cycle inner tube valve with rubber to the width of the cork, foot pump.
We talk to the section about weight and power. The battery and elastic band powered car would be smaller than the water jet. We also talked about actual car power, could you use elastic bands or water? The groups had 10 mins to decide on a design for their cars. Their was plenty of adult support, so that they could ask advice.
They played a game to decide who would build what design.