Hi folks. My name is Cameron
And today I'm going to speak to you about Faraday's Law
Imagine we can take all that we know about electromagnetism
and compact it down into just four short equations.
That's what James Clerk Maxwell did in the 19th Century.
He was able to show that these four equations
told us everything that we know about electromagnetism.
But one of them, Is called Faraday's Law.
named after Michael Faraday himself.
He demonstrated that electric and magnetic fields
are closely linked and can actually induce one another.
Let's take a closer look at the equation in its integral form.
It shows us that a change in magnetic flux
through a surface
will create a circulating electric field.
But what is magnetic flux?
So lets picture a bar magnet with its magnetic field lines
If we put an an open surface near the magnetic
The flux is going to be the total amount of field lines
flowing through the surface.
And if we move this magnet closer
you'll see that more field lines go through the surface.
increasing the flux
But, according to Faraday's law, changing magnetic flux
induces a circulating electric field. So if we replace the
open surface with a coil wire, we would get
induced current flow.
This is what is known as electromagnetic induction
However, it is worth noting that
Faraday says that it's a change in magnetic flux
and a stationary magnet with a constant magnetic field
will produce no electric field at all.
And here's some footage from the archives,
which will show all of this, in action
This might look like a regular, uninspiring laboratory.
but inside, as we shall see
there is something quite extraordinary.
Here we have found a peaceful coil of wire
preparing itself for the harsh winter ahead
At this time of year the coil has become docile
while it conserves energy.
But we should be able to test Faraday's law
without disturbing the coil, and we can do so
with this magnet
We can connect our ammeter to the coil while the coil remains
relatively immobile.
Now we can see, as we insert our magnet into the coil
the change of magnetic flux induces a current.
The current then returns to 0 while the magnet is stationary.
As we pull out of the coil, the change in
magnetic flux is in the opposite direction
so we get a negative current.
which then returns to 0 while the magnet is
outside the coil.
So there we have it, by changing
the magnetic flux inside a coil of wire we can
create a current in the wire just as
Faraday proved. And now, I think we should
leave the coil to rest.
A big thank to the guys down at the archives for
digging that one out for us.
Yeah [smug]
Faraday's law still has its uses today, one  of which
is in generators.
converting mechanical energy into electricity
Which can be delivered to our houses.
If it weren't for Faraday,
Electricity wouldn't be so widely available
That's all for this video, I hope you've taken some
knowledge away with you
and thank you for watching.
