Hello, Nige here.
And today on Imagine This, I'm sticking some photos to the fridge.
Let's put this one of me looking cool surfing over here.
And this other one of me looking cool with my lab coat over here.
Why are there so many?
Hang on.
Oh no, you ran out of magnets.
But I still have heaps of cool photos of me that I want to stick up.
Can you make another magnet?
Hmm.
What do you think magnets are made of?
I think they're made of magnetic rocks, different types of metals.
This spoon is metal, so maybe I could use this instead.
No.
No.
How come?
Because there's nothing magnetic in the spoon.
I think it's because it's not the same type of, like, metal or something.
Most metals are magnetic, but not all of them.
I know.
What if I throw it?
All right, give it a try.
No, it didn't work.
Too heavy.
We've had lots of questions about magnets.
Hi, my name's Kira and I'm seven years old.
My name is Ollie and I'm five years old.
My name's Henry and I'm three years old.
My name is Sophie.
I'm six years old.
My name is Fred and I'm seven years old.
My name's Jimmy and I'm seven years old.
Hi, I'm Oscar.
I'm seven years old and I'd like to know how are magnets made?
How do magnets work?
Why do they push and pull?
It's not sticky like glue, is it?
Maybe slide?
Maybe vibration comes and it sticks it.
Metal magnetic beams inside it?
I know who can teach us about magnets.
Dr Cathy Foley.
She's a physicist and an expert in magnets.
She was even... the Chief Scientist of Australia.
The boss of all the scientists?
Kinda.
It's the top science job in the whole country.
Let's go visit Cathy in her office.
Hi, Dr Foley.
Hi, Cathy.
Hi, everyone.
Lovely to see you.
What have you got in your hands, Cathy?
Yeah, what are you playing with?
Oh, these are just some little magnets.
They keep my hands busy while I think.
That's what we came to ask you about.
Yeah, what are magnets?
And how will they work?
Well, magnets can come in all shapes and sizes, and they're used in lots of ways.
But I can't see anything.
Where's the magnet power?
We'll need to take a closer look at what's going on.
So how about we use our imaginations to magnify these magnets?
Yeah.
Let's make them really big.
Yeah.
One, two, three. those paper clips.
All the office stuff is flying into the magnets.
What's happening?
Because there's other magnets inside.
Correct.
All magnets have something called a magnetic field.
A field?
There's no grass on them.
No, the magnetic field is the area where you can feel that invisible push or pull of a magnet.
They stick together and push away.
Sometimes the bigger magnets... have a stronger magnetic field.
So I think when we supersized our magnets... We made them more powerful.
And then every other magnetic object nearby was pulled in.
But this metal stapler isn't normally a magnet, right?
Or these paperclips?
They're not going to stick to the fridge.
No, these items are what we call temporary magnets.
They're made up of metals that can be made magnetic for a short time.
Bridge magnets and these bar magnets... are called permanent magnets because they stay magnetic.
Very cool.
Neodymium is very good at staying magnetic.
So this is what most of the magnets you're familiar with are made of.
One of the ends of the magnet we call the north pole and the other the south pole.
Where all the penguins are.
No, that's not it.
Not quite, although you're not far off.
The poles of a magnet are where the magnetic field is strongest.
The poles repel or attract other magnetic objects.
Let's test it out, shall we?
Yeah.
Let's push these two bar magnets end to end.
Ready?
Push!
Nothing's happening.
Are you even pushing it?
I really am.
But it's like the magnet is pushing back. pushing apart from each other like an invisible power.
You must have two South Poles or two North Poles facing each other.
In that case, the magnets will repel or push the other one away.
Oh, come on.
We're strong.
We can do it.
Let's try again.
You'll just tire yourself out.
No force in the universe could push these sides of a magnet together.
OK, let's try the other way.
Did you see that?
They stuck.
It moves by itself.
The magnetic field pulled them together.
So if a magnetic field is what makes a magnet magnetic, what's making the magnetic field?
We'll need to take a closer look at their atoms.
They're really small.
Tinnier than bacteria.
They're way too tiny to see, even with a microscope.
So let's use our subatomic spectacles.
What's that?
Oh, just something I imagined up.
They'll help us see things on the atomic level.
What should we look at first?
Let's check out this metal paper clip on my desk first.
Ready to go quantum.
We've never gone there before.
Subatomic spectacles on.
Oh, cool.
I can see here's the tiny little things buzzing around.
They're atoms.
Whoa.
There are atoms everywhere.
Whoa.
That's amazing.
You know, I've heard you can't trust atoms.
Why not?
Because they make up everything.
Yes, all the stuff in the universe is made of atoms.
Everything?
Jellyfish?
Houses?
What?
Yep.
A paperclip is made of billions and trillions of atoms, and each atom is made of even smaller stuff.
Even a tiny thing has so much other tiny things inside it.
What's that noise?
Electrons.
They're whizzing around all the atoms that make up this paperclip.
Electrons?
I think it's lots of teeny bits of electricity.
And I think they're in power lines?
Yeah.
When they jump around in clouds, they become lightning.
And when they flow through wires, they become electricity.
Yes.
Electrons make electricity.
And they are essential in making a magnet magnetic.
That's a lot of electrons.
They move so fast, they're just a blur.
So it looks like a cloud around the atom.
Let's slow these electrons down so we can see them better.
Hey.
They're talking.
I'm here too.
Guess you forgot about me.
Do they sound a bit sad to you?
Don't mind them.
Electrons are always negative.
Whatever.
Electrons move around an atom, but they never bump into each other.
We call this movement spin.
This special spin gives them a power.
What is it?
It creates a very tiny magnetic field and it turns them into mini magnets.
The electrons are spinning around the atom very quickly because of their electricity.
The reason they're spinning around it, I think, is because they don't like each other.
Correct.
Who cares?
I like my own space.
Yeah, I prefer to spin solo.
Me too.
Picture all the electrons spinning on their own. going in lots of different directions.
They each have a magnetic field, but it's very weak.
Now let's take a look at the atoms in those magnets of mine.
Whoa!
The electrons in the magnet are all spinning the same way.
They're not trailing all over.
Synchronized spinning.
We have more pull when we spin together.
In magnets, the electrons all line up in the same direction and spin together like they're in a team.
Teamwork makes the dream work.
Or their mini magnetic fields join together to create one strong magnetic field.
They're getting stronger.
OK, you've seen how electrons move by themselves in a paperclip and how they move together in the magnet.
Now let's introduce them to each other.
Let's just adjust our spectacle settings.
Okay, I can see the electrons in the paperclip.
No coordination.
Hang on, something's changing.
Hey, what's over there?
I don't know, but it feels like we should all spin this way.
It's like the electrons have noticed the magnet.
It's pulling me in.
Whoa, the electrons are all turning towards the magnet.
And they're all starting to spin the same way.
Whoa!
The strong magnetic field of the magnet is attracting the tiny magnetic fields of the electrons and pulling them into line.
This feels different.
They've started spinning all together in the same direction.
So now this paperclip is magnetized.
We're magnetic.
The paperclip and the magnet are stuck together.
Until you take away the magnetic field, of course.
I'm tired of this.
I'm doing my own thing.
Yeah, this is cool for a while, but I want to be on my own now.
They're going different ways again.
When we took away the magnet, the paperclip's electrons went back to spinning on their own.
The effect wears off after you take the magnet away.
So, while your toys or fridge magnets will stay magnetic, a paperclip will only be magnetic if it's close to a strong magnetic field.
Let's take these subatomic spectacles off. and get things back to regular size.
That was so cool.
And we never even left your office.
Yeah, it's amazing how much stuff is going on.
We just can't see it with our eyes.
But hang on, Cathy.
Aren't electrons in everything?
Yes.
You can't use a magnet to make the electrons in this piece of paper line-up, though, can you?
Or this plant or any other stuff, like my dog her name's beans.
No, this only works with special metals like iron, nickel or cobalt.
That's why paper or plastic can't be made magnetic, or really most other things.
Sorry, beans.
Before you go, can i show you my favorite magnet?
Yeah, follow me, Kathy.
Did you imagine us down to Antarctica?
Yes, we're at the South Pole.
Remember how magnets have poles?
The North Pole and the South Pole?
Well, the Earth has both of those because the Earth is a giant magnet.
What?
Remember some of those metals that can be magnetic?
Iron and nickel?
Yes.
Well, deep underground, the outer core of the planet is made of iron and nickel.
The planet is made of metal?
It's not solid metal.
These metals are hot, liquid, swirling around.
Which makes it act like a magnet.
Correct.
It's not very strong.
It won't make your magnet stick to the ground.
But it's how compasses find north and even protects the planet from the sun.
How?
We might have to save that for another day.
Yeah, I'm pretty cold and this penguin keeps bringing me fish.
He likes you.
Well, it's back to the lab for me.
Thanks for teaching us about magnets, Cathy.
Bye, Cathy.
So Ollie Fred Jimmy Sophie Henry, Oscar and Kira magnets work because they have invisible magnetic fields.
Not like a football field.
It's the space where magnets pull or push on other magnets.
It attracts or repels.
Magnetic fields come from electrons, tiny particles that spin around in atoms.
In most objects, electrons spin in random directions.
Each one is like a mini magnet, but it's really weak.
Stuff that's not a magnet.
Like plastic.
Or a tennis ball.
Or beans.
But in magnets, the electrons line up and spin the same way.
They join forces.
To create a strong magnetic field.
One that's strong enough to pull other electrons into line too.
Like in things made of iron, nickel and cobalt.
So it's magnetic.
We know how this happens, but not exactly why it happens.
It's a rule of the universe.
And it helps explain lots of things.
Not just how magnets stick to paperclips.
And my toy train.
But electricity and wires and clouds.
Like lightning.
The whole Earth is a magnet.
Right down to the quantum world of subatomic particles.
