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Science Made Easy...

Electricity Demystified!

Ever wondered about volts, amps, etc? why electricity is measured in these different things, and what they mean?

Part of the reason why electricity seems so mystifying is because you can't see it. But such things as voltage, current, etc can be explained by imagining electricity in cables as if it was water flowing in a pipe. Voltage is the "pressure of electricity", and Current is the flow-rate.

Voltage is potential, like a head of steam, a static pressure of electricity waiting to flow.

Current is the flow rate of electricity and is measured in Amps. If electrons are the atoms of electricity, you'd see six million million million of them flow per second for each amp of current there is. (electrons are very small - many household appliances have several amps as a working current).

You can spot the electricians, as they talk about a voltage that there IS, but talk about a current that flows through something.

Power is easy to work out, as it's voltage multiplied by current. It's like hydroelectric power stations having a power which is the voltage (height) of water x the current (amount of water flowing). The standard power socket in the UK is 240 volts, and can supply up to 13 amps. So, the maximum power is 240x13 = 3,120 Watts. A three kilowatt electric fire is at the limit of what can be plugged into a single socket.

Similarly, you can turn this around and work out that a 100 watt bulb requires a current of 100 divided by 240 = 0.4 amps.

But on electricity bills you don't pay for power, you pay for Energy. Again, there is an easy relationship for working these things out. Energy is power x time. A one kilowatt (1000w) heater running for one hour has used one kilowatt-hour. A kilowatt-hour costs about 7p (2001) generally, but is cheaper at night. You can always work out these things scientifically; for example a fridge with a power of 100 watts, in ten hours uses one kilowatt-hour. See the Difference between Energy and Power

Because of the distinction between volts and amps, electricity is distributed at high voltage to keep the current low, which saves money. See power lines

Also, in case you're wondering, how many appliances can you plug in a power socket without overloading it?

If you like the explanations here at Zyra.org.uk , you may be interested to see this: [response]

Since writing this page, I've found someone else has written a book called "Electricity Demystified". If you're looking for that, it's available on Amazon