Now we turn everything around and see what happens when we move a coil in a magnetic field.
Youtube video, suitable whether of not you have the board with you.
See board images.
Tutorial guide for when you have the board with you.
On this board you will find a length of wood with a magnet on the end. There is a black tube on the board, push the magnet into the tube and move it up and down while watching the ammeter. The first time I did this was a real WOW moment – moving the magnet through the coil is generating electricity – isn't that amazing?
So, this time we are not making something move passing a current through a coil, but creating electrical current by moving something (here the magnet)! This idea is at the core of every wind turbine, hydroelectric and tidal electrical generation system! This is how it’s done; we simply move a magnet near a coil or move a coil near a magnet and we have electrical power.
The bigger the magnet and coil and the faster we move it, the more power we get. Now look at the machine on the board, it’s very similar to the first electric motor we looked at, but this time we are moving the coil and this is generating electricity. With the switch pointing at LEDs have a go at turning the handle and see what happens (but be gentle please) – you should see one of the two lights come on. Turning the handle the other way will turn on the other light.
The two meters can be selected with the rotary switch and this gives us the voltage and current being produced. You will also see the meters showing the current and voltage have reversing if you turn the handle the other way.
Look at the first ammeter near the tube, its labelled uA – this is microamps. Each of these is one millionth of an amp – very small. A thousand of these is one milliamp. So, while we are generating electricity, it’s a very small amount. Now look at the device on the other side of the board, we have two bigger magnets, a bigger coil and the movement is greater, this means we are going to create more power. As you turn the knob, note the readings you are getting on the meters. Remember this time the current is in milliamps so 10 would by 0.01 amps for example. Convert the current you are getting on the meter into amps and multiple it with the number of volts. This gives you the power you are generating in watts. It will be very small, but it’s using the same idea as many of the machines that create our electricity. They are so big they measure the power they generate in either kilowatts (thousands of watts), or even megawatts (millions of watts)!
Search solar panel systems for houses online and get an idea of how any kilowatts (Kw) they can produce, then do the same with wind turbines – these could be a number of Kw or even Mw (Megawatts).
Some follow-up ideas to try...