There are two practical uses of elctromagnetism on this board, one is fun (the trembler bell) and the other rather boring (the relay).
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.
So how can we use this idea that a coil can become a magnet? A great place to start which is rather fun is the trembler bell! You can see the coil and it has been placed very close to an old steel hacksaw blade which is very springy. If we connect the coil to the batteries, it will become a magnet and that will pull the hacksaw blade towards it. You can make this happen by pressing the blue button, do this but don’t hold the button down, release it straight away. You should see the blade move and the end of it will hit the bell and make a sound. When you let go of the button, the blade goes back to where it was. Now it wouldn’t be very clever to have to keep pressing and releasing the button to make the bell ring! Press the button again and notice the gap that appears between the big and little blades. When the blue button isn’t pressed, the two are connected, but when it is pressed, they are apart! Wow it’s a kind of switch open and closed by current flowing and stopping in the coil. If we include this switch in our circuit, it will start closed allowing current to flow through the coil, but as soon as this happens, the switch will open and that cuts of the flow of current meaning the blade moves back and close the switch again. That starts the current flowing again and pulls the blade which opens the switch again! Press and hold down the yellow button, this circuit includes this switch so the blade will vibrate back and forward hitting the bell as it does so, it’s that cool!
A relay is an electronic component (part) that a switch controlled by a current flows through a coil. Press and hold down the green button. The yellow light will come on. You can see that the circuit is going through a switch in the relay. When you press the red button as well, the coil will throw (pull) the switch and the green light will turn on and the yellow light goes off. You might be able to hear the switch being pulled by the coil as it turns into a magnet.
Notice that when the bell in ringing there is a small spark in the blade switch. This occurs because the coil keeps being turn off and on. Why this happens will be explained later and we will need an electronic component called a flywheel diode to stop it.
Relays are used in many electrical devices when we want a small current to throw a switch taking a large current. When you start a petrol or diesel car, turning the ignition key will throw a relay that connects the starter motor to the battery. This is because the starter motor takes a lot of power and so a lot of current needing a very thick wire and we would not want all of this going through the key switch.
Some follow-up ideas to try...