Electricity is a very important means of transport of energy from one place to another --

• because it is very easy to connect and disconnect energy-using devices;
• because it is easy to convert mechanical energy into electrical energy and vice versa;
• because it is easy to transport electrical energy;
• because electrical energy is transmitted very rapidly (almost at the speed of light);
• and because there are many physical effects involving electrical energy which make possible conversion into light, sound, motion, force, heat, cooling, and rapid transmission of information.

Why study electrical current?

We need an electrical current to flow for an electrical system to do anything. Because we can't see the current, it isn't obvious that what is happening. We started with a study of flowing fluids because this provides a useful analogy. It will take some careful observations to establish the truth and relevance of the analogy between electrical current and fluid flow.

There are some differences between electricity and other fluids. Unlike water, that will leave its pipes, electricity will usually stay in the wires. We don't have to worry about a broken wire flooding the basement with electrons! There is no electrical equivalent of the lawn sprinkler, until you get to really high voltages.

The section on electrical current