• Charges and fields:

play with this simulator to visualize the E field lines. Change the amount of charge. Make different arrays of positive and negative charges. Measure the voltage in different places.

Do they agree with what you expect?

• Charged objects:

in this video you can see how to build a  Van de Graff electrostatic generator. Instead of a metallic ball it uses a soda can (empty of course 😉 ). The way to charge it is to rubber it with a rubber band. To do this more efficiently they use an electric motor. Once the charge in the can reaches certain value it produces a spark and recharges again.

Why does the ‘conffeti’ is blown up when you put it on the can?

• Rupture field:

Another interesting device is called the Jacob’s Ladder. Here you can see a spark jumping between two electrodes at high voltage. But:

How can I produce a high voltage with just four AA batteries?

Why does the spark jump always in the bottom of the ladder?

Why does the spark ‘climb up’ the ladder and not the other way around?