Earthing gives charge on metal equipment a path to the ground. This prevents charge build-up and reduces sparks that could ignite fuel vapour or combustible dust.
A student uses this apparatus to demonstrate the effect of electric charge.
He pours some fine powder into a funnel.
The fine powder moves through a length of plastic tubing and falls into a metal can.
The metal can rests on a metal cap.
The metal cap is connected to a thin piece of metal via a metal rod.
When the powder lands in the can, the thin piece of metal moves away from the metal rod.
The student suggests that this demonstration is similar to refuelling an aircraft.
The powder represents the fuel and the metal can represents the fuel tank in the aircraft.
Explain how the student should modify this apparatus to demonstrate how to minimise the dangers when refuelling an aircraft.
You may add to the diagram to help your answer.