First, you should make a coil.
The coil is made of copper because you have to flow current to it.
Next, the coil is connected to a component stereo as shown here.
Third, put the coil on the magnet, and adjust the volume.
You can observe that the coil is dancing.
Put the coil and magnet on a can or plastic trash box, and etc.
You can listen to the music!
This is a hand-made speaker.
Lastly, let's try to listen through bone conduction.
If air vibrates, this is a speaker.
On the other hand, if bone vibrates, this is a bone conduction headphone.
Hope you and your kids enjoy the exam.
