Welcome to our second episode on electromagnetism,
one of the four fundamental forces
of physics.
Like I said last time, there are two aspects to  electromagnetic force
Electrostatic force which builds up a charge in an object and can travel in the form of an electron stream
and Magnetic force which is responsible for the way magnets work.
But even though their effects look different to us,
they are in fact, one of the same.
Hopefully, you remember that electromagnetism acts on objects that have electric charge,
this charge creates a field around an object.
But a magnetic field is a little bit different from an electrostatic field.
For starters, unlike a charged particle which can either be positive or negative,
a magnetic field has both a positive and a negative area, what we call a North and South poles.
Magnets always have both poles, no matter how many tiny little pieces you cut them up into
But magnetic poles interact much like single pole charged particles,
the same poles repel each other and the opposite poles attract.
And this like with electrostatic force because its the same force
Magnetic force is carried between objects by photons.
To demonstrate that electrostatic and magnetic are, in fact, effects of the same force
you can create magnetism using electricity
A simple electromagnet is just a coil of wire in which when a current is passed through,
it generates a magnetic field.
You can make one yourself by passing an electric current though a wire wrapped around a nail or a screw.
Switch on the current, and the screw becomes a magnet, switch it off again and the magnetism disappears
The magnets on your fridge are made basically the same way,
only with a lot more electrical power, and using special materials to retain the magnetism.
And, hey, you know what else is an electromagnet?
You're living on one.
The constant churning of the molten iron in the Earth's outer core crates electrical currents
and those currents generate the Earth magnetic field.
Which has proven to be super useful for things like navigation and since,
the magnetosphere protects us from solar wind -- not being dead.
So an electric current produces a magnetic field, the reverse must also be true,
and in fact, yes, you can  generate an electric current using a changing pattern of magnetism.
If you put a coil of wire within a magnetic field and continuously spin the wire or the magnet,
so that the magnetic field inside the wire fluctuates,  electricity will flow through the wire.
And this is really exciting cause it's the reason why we have electricity.
All you have to do is keep the wire or the magnet moving, and you'll have a continuous source of electricity.
Stop moving and the electric current will stop.
This is how pretty much every source of electricity in the world works,
from wind turbines, to hydroelectric dams, to coal and nuclear power.
The only big exception is solar power, which is really interesting, so we did a whole episode on it.
Which brings us to the conclusion of our series on the four fundamental forces of physics.
If you have watched all of them, you are now a master, well not quite a master, but you're getting there.
If you don't feel like you have quite mastered them, you can go re-watch those episodes
Also we'll suggest some books down in the comments that you can continue to develop
your understanding of THE STUFF THAT MAKES THE WHOLE WORLD WORK.
Thank you for watching this episode of scishow, if you have ideas or suggestions or questions,
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