## Adrian's Wall - Teacher Notes

Adrian's Wall

Adrian is planning a charity event which will involve people holding hands in a continuous line.

He thinks that the best place to do this is along the 100 mile (160 km) border between England and Scotland.

How many people will be needed to make the human wall across the country?

a) if they link arms

b) if they hold hands

**Sample Answers**

*Pupils may want to build a mini-wall to get an idea of distance covered by each participant.*

When linking arms each person takes up about half a metre, if they link as loosely as possible this might be increased to nearer a metre. So to cover 160 kilometres it would require at least 160,000 pupils and at most 320,000.

If they are holding hands each person could stretch to somewhere between 1.5 and 2 metres, and we want the wall to be about 160 km. So an average of 1.6m will give some 'nice numbers' - 1000 people will stretch about 1.6 km and 100, 000 will stretch about 160 km.

Putting an upper and lower bound on this gives an estimate of between 95,000 and 125,000 people.