EM3.5 Lightning Rod Simulation
The Van de Graaff generator is used to charge two large horizontal metal plates. On the lower plate is placed a sphere on a stand. When the potential difference between the two plates is large enough, an arc of lightning is seen between the sphere and the upper plate. When a sharp point on a stand is placed next to the sphere, no arc is seen. This shows that charge continually builds on a sphere and discharges at a point. This is why lightning rods come to a point. Another apparatus is shaped like half a sphere attached to a cone. Sometimes this is hard to see, so dimming the room lights would help.
Equipment Location: E11