ABC Listen.
Hello, it's Nijia.
And right now on Imagine This, the sun is going down.
The sky is changing colour.
It's sort of purply.
And it's getting dark.
It just sounds like the trees rustling.
I hear cicadas.
And something else is happening.
All the lights are going on.
There's one and another one.
Yeah, everyone's turning on their lights.
And that's what today's question is all about.
Hi, I'm Jonty.
I'm five years old.
I want to know how the lights light up.
Is it the same as light from the sun?
No.
Is it like a little fire inside the bulb?
No, it is power.
It's electricity.
Ah, electricity, of course.
Hang on, how does electricity make light?
Um, well, I think it's got a cord in it.
Because it's charged up.
And then I think that the cord makes a zap when it comes out into the light bulb.
I don't know.
I know someone who does.
Let's talk to Professor Chenupati Jagadish.
He's a physicist. and the President of Australia's Academy of Science.
And he knows all about electricity and making light.
Hello, Professor?
I can't see.
It's too dark.
Ah, there you are.
Sorry about that.
You caught me changing the light bulb.
Hi, Nish.
Hello, kids.
Hello.
Hi, Professor.
What happened to your light bulb?
It's an old one.
It stopped working.
So even when I flick the switch at the wall, the light won't come on.
That's what we came to ask you about.
How do lights light up?
How does a switch work? electricity has to travel a long way to make it into your light bulb.
Where should we start?
Let's see what's happening inside the light switch.
We'll have to use our imaginations to see inside here.
That's easy.
Yeah, we've had a lot of practice.
This perfect and remember, this is just for our imaginations.
You must never touch the insides of wires or light switches or anything that's plugged into electricity, because electricity is very dangerous.
Yep, electricity is very powerful.
It can do so many wonderful things, but only if we use it safely.
Okay, let's go inside a light switch.
There are wires going in and wires going out.
Wow, i can see wires and metal things.
The wires on one side are connected to the home's electricity and then the wires on the other side are connected to the light.
I think When you turn the light switch on, that sends a little tiny message all the way up into the light with little microbe guys.
Almost The light switch is like a little door for the electricity.
When you turn it on, the door opens and electricity can move through the wires to the light.
Let's give it a go.
Hi.
Hi.
Hello.
Excuse me.
Can I just get through here?
Make room for me please.
Coming through.
Hey, we've met them before.
They're electrons.
Yes, all electricity is electrons.
In nature, it's lightning.
Yeah, we've learned about lightning.
Electrons don't like being stuck all together, so they move to a place where there's less of them.
With lightning, it means they jump from cloud to cloud, or from a cloud to the ground.
Lightning is very fast though, and it is very powerful.
It's not very useful if we want our lights to stay on, so instead we need a steady flow of electrons like this one.
We call it a current, so by opening the door in the switch, You're giving them more room, and they rush through the wire like a river of electrons.
That's right.
Switching the light switch off closes the door on the electrons and stops the flow.
Hey, they're gone.
Until you flip the switch again.
We're back.
Let's follow the current along the wire to the light bulb.
We can see how this electricity makes light.
We're inside the walls.
Whoa, there are so many wires in here.
Is this safe?
Can the electrons jump out of the walls?
We cover metal wires in special plastic.
Electricity can move freely through metal.
That's what we call a conductor.
Conductor.
But electricity can't get through most plastics or wood or glass.
We call them insulators.
Insulator.
So insulators, like plastic, protect us from electricity.
Even though we are safe from electricity when the wires are covered in plastic, we should still never touch them.
Because I think you'll get hurt.
And we should also be careful around plugs, switches and sockets too.
Hang on tight.
Here comes the light bulb.
Whee!
Whoa.
Cool.
It feels like we're in a fishbowl.
Yeah, it does.
This bulb is an LED.
LED?
A light emitting diode.
It's a special type of microchip.
Microchip?
Can I eat it?
I love chippies.
It's not that kind of chip.
No.
They're basically like little brains for computers.
That's right.
They can be made to do lots of jobs, especially in computers and phones.
But the job of this microchip is to create light.
When the electrons move through the microchip, they make photons.
They're giving off light.
That's right.
Our light is made of tiny particles that we call photons.
So electrons pass through the microchip. and give off light.
Hey, where are they going now?
Oh well, that wire connects back to the light switch.
The electrons are leaving.
But the light's still on.
The electrons need to keep moving.
We call it a circuit.
Oh, like a loop.
Yes.
Round and round and round and round.
I'd get dizzy.
So, while the light is on, the electrons are moving round and round because they're trying to get away from each other.
So the flow of electricity doesn't stop.
Yep, until you turn off the light switch.
And that's when you've closed the door.
But they're ready to go again when you flick on the switch.
And you know, your home is on a big circuit too.
What?
Really?
Come on, let's follow the flow and see where it takes us.
Whoa, we're moving through the wires.
Wow!
Hey, we're in a bigger wire now.
Look, we're outside.
We're heading for that power line.
Those poles.
The wood poles.
Or those black power lines.
Excuse me.
Where do you think you're going?
What is that?
This is a transformer.
They look like robots?
Yeah.
They are the boxes you can see on the power lines along the street.
That's right.
I'm in charge of the voltage.
I say who goes where and how much of you.
Electricity is sent into our houses from these transformers.
There are power transformers.
Yes, they make sure we don't get too many electrons all at once, so we can have nice and steady electricity.
Oh, let's head this way.
Oh yeah, more space.
So much room here.
Hey, hey, not all at once.
Slow down.
They're going onto the house on one wire.
But where are those going?
It looks like the electricity is going into our homes, but it's also coming back out again.
Just like the loop between the light switch and the light bulb.
Oh, because we're on an even bigger circuit.
Yes.
Where does it go?
All the way back to the power station.
Whoa, we're at the power station.
It's so noisy.
How do you think electricity is made?
We know, in clouds it's made by lots of ice bumping around and knocking loose electrons until there are too many and they need to spread out.
But how does it work here?
Do you catch lightning?
Lightning is very powerful electricity, but it is too random.
We don't know when it's going to strike.
Here in a power station, we can make electricity.
How?
Well, this one uses spinning magnets.
Magnets?
Are they electric?
We call this machine a generator.
By making special magnets spin really fast.
The energy made by all the spinning can be turned into electrical energy.
There are different ways to make the magnet spin.
Mostly it's done with steam, like when you boil the kettle.
Some generators burn coal or use gas to boil the water, but that's not very good for the environment.
But some generators use wind or water instead of steam hydro power.
They use water, they get electric things and then it goes.
The movement of lots of water or lots of wind can also make the magnet spin and can be turned into electricity.
Wind power is where you put a big wind wheel and then when the wind blows, it makes electricity.
What about solar power?
Solar power is a bit different.
Sol means sun.
When it bounces on, things work.
It's power from the sun, and it's good for our environment.
I love solar panels.
They're so great.
Come on.
We can follow the power lines all the way home.
So now you have seen how electricity moves through wires from the light switch to the light bulb and back again on a small circuit.
And from our homes to the power station on a bigger circuit.
It's pretty cool.
But remember, electricity can be really dangerous.
It's great to learn about, but we must never touch any wires or play with electronic devices without a grown-up.
Definitely.
Every time I turn on the light.
Now I'm going to think about how far that energy has travelled to get to my house.
Thanks so much for showing us how lights light up, Professor Jagadish.
It was illuminating.
My pleasure.
Bye.
Bye.
Bye.
Thank you.
So, Jonti, lights light up using electricity.
The flow of electrons.
When you flick a switch to turn on a light, you open a door for electrons to move through.
They move safely through wires that are protected by plastic inside our walls all the way to the light bulb.
Inside an led light bulb is a microchip, but you can't eat it, and when electrons move through the microchip they create light for a light to light up, or toasters to toast, or heaters to heat.
Electrons need to keep moving.
They don't like each other.
They need space.
So while the door inside the switch is open, electrons will move around and around.
Non-stop.
This is called an electrical circuit.
Our homes are on a circuit too, with electricity moving in and out from the power lines on our streets.
The electrons will move back and forth from towns to big generators that make electricity by burning coal or gas to spin large magnets.
But more and more we're using the power of the wind, water and sun to keep the electricity flowing and the lights on.
Imagine This is an ABC Kids Listen podcast, hosted by me, Dr Neeraj Lal.
A big thanks to our guest, Professor Chenupati Jagadish, and to all the kids who helped make the podcast.
Today's episode was written and produced by Sumiya Bella, with sound design by Wayne Ewan, and was made on Gadigal Wurundjeri, Woiwurrung and Maori lands.
Our senior producer is Emma Gibbs.
For more podcasts to play, music to move and stories and soundtracks for sleep.
Download the ABC Kids Listen app free from your app store.
