Since designing this workshops we have run it hundreds of times and feel works best run in 90 minutes with 30 pupils.
Working in pairs, pupils contruct the constituent parts of a 4m tall wheel laid on its side. Once stood upright, the stucture really does look impressive. Once the axel and two chairs or PE tables are in place pupils can spin the wheel. If time allows the pupils can also crawl underneath on their back to see the wheel turning above them.