Lesson video

Hello there, My name is Mr. Wilshire, and in this lesson we'll be looking at sustainable sources of electricity.

The outcome for this lesson is, I can identify sustainable sources of electricity and describe their benefits to the environment.

There are some key words to remember as we work our way through the lesson.

The first is generate, the next fossil fuels, then greenhouse gas, global warming, and finally, sustainable sources.

Don't worry if you're not too sure what some of these words mean as the definitions will appear on the screen for you now.

If you need to, you can pause a video here and have a recap on what they mean.

Restart the Video when you've done that.

The first part of this lesson is called burning fossil fuels to produce electricity.

Now, we use electricity in our lives every single day, but do you know where the mains electricity that you use comes from? Here, you can see an example of a plug being plugged into a plug socket.

Maybe you've got some examples of this in your home or your school.

Have a think, where does the mains electricity come from? Hopefully you were able to discuss and have a think.

Now, traditionally, electricity is generated in power stations.

Now, lots of cables go into and out of power stations so that the electricity can run in a huge circuit all the way around the country.

You can see there that there's lots of chimneys in the background there that's able to pump steam out that generates the electricity.

So do you know what traditional power stations will burn to generate electricity? I gave you a clue in the last slide.

Have a think now, what traditional power stations burn to generate electricity? In these pictures here, you can see an example of coal being burned.

You can see fuel being put into a car, could be petrol or maybe diesel.

And there is also a gas burner that's burning some gas to have a flame on it.

All of these are examples of different ways that power stations will burn things to generate electricity.

They burn coal, oil, natural gases, which are known as fossil fuels.

Now, the coal is put into great big towers, burned, and then the steam helps to generate the electricity, oil can do the same thing, and so can gas, all of these things are fossil fuels.

So Aisha asks, "Why are they called fossil fuels?" Jacob says, "Aren't they made from fossils from millions of years ago?" Hmm, what do you think, do you know? Discuss.

Well, they are called fossil fuels because they come from natural resources.

They come from our planet.

Fossil fuels are made from fossilised plants and animals from over millions of years ago, all buried deep beneath the Earth's surface.

Here you can see some cold beneath the Earth's surface.

You can see a buildup of natural gas and of course, some oil there as well.

Now, it doesn't always look like this underneath the Earth's surface.

Some of these things may be very far apart from each other, but this diagram here gives a good example as to what could be found, but not always in the same place.

To get there, people need to drill down into the Earth's surface to retrieve some of these materials.

I wonder how they've ever found them in the first place.

So as I said before, yes, to access these fossil fuels, we need to dig down into many different layers beneath the Earth's surface.

You might need to mine digging down hundreds and hundreds of metres into the Earth's surface to get some coal.

Or maybe you need to drill into the Earth's surface to get a pipe in there and then pump oil out of it using a dredging pump, a little bit like this.

So Aisha says, "Well, my mum says that fossil fuels are really bad and that we shouldn't ever use them." Hmm, well, that's true.

One concern is that we're actually running out of fossil fuels, and that one day there won't be any left for us to burn or generate electricity.

That would be really bad, wouldn't it? We wouldn't be able to get anywhere.

We wouldn't have any electricity either.

Humans have used fossil fuels since the 1800s for heating, transporting and generating electricity.

Soon we will have used up all the fossil fuels on Earth.

Here you can see some coal miners all lining up outside a mine shaft entrance in 1926.

It's black and white because didn't really have access to colour photographs back then.

Jacob says, "But aren't more fossils of animals and plants being created all the time?" Here you can see an example of drilling for fossil fuels far out at sea using a platform like this.

Now, there are limited amounts of fossil fuels beneath the Earth's surface.

It takes millions of years to form them.

We need more fossil fuels more quickly than they're being created.

So even though animals are dying now and then slowly being transferred into the Earth, this is something that's taken millions of years.

So it's not really something that we can regenerate ourselves, is it? Andeep says, "Well, my stepdad says that fossil fuels are damaging the environment." Hmm, another concern is this.

It's that fossil fuels create harmful gases.

Harmful gases can cause air pollution and lead to breathing problems like asthma.

So one of the gases produced is carbon dioxide, which is a greenhouse gas.

Lucas asks, though, "What is a greenhouse gas?" Oh, what do you think? What's a greenhouse gas? Discuss.

Well, a greenhouse gas collects around the Earth and acts like a bit of a blanket.

Here you can see a picture of the Earth and the sun.

There's also that blue glowing layer above the Earth there, which is the layer of greenhouse gases.

Now, they trap all the sun's heat, causing Earth to get warmer.

We need some greenhouse gases to make Earth warm enough to live on.

But in recent years, the amount of greenhouse gases has become a little bit too high, and the Earth's climate is changing.

Aisha says, "Well, I like it warm.

Why does it matter if Earth becomes warmer?" Hmm, well, I like it warm as well, but I wonder why it would matter so much.

That layer of greenhouse gases is there to help trap in the sun's heat.

So hopefully, if everything gets nice and warm, that might mean that when we have our summer holidays, well, we could just stay at home.

But why does it matter if Earth does become warmer, though? Have a think.

Hopefully you've had a chance to discuss that question.

Let's have a think.

Now, if the Earth does get a lot warmer, that could mean that it's a little bit too warm for us to live on.

The global warming is the result of the processes that cause the average temperature of the Earth to rise.

And as the temperature of the Earth rises, habitats are changing, and some plants and animals are finding it harder to survive.

Now, I know, for example, in my life, I'm finding it quite hard in the summers at the moment because it's a little bit too hot, especially without something to cool me down.

So I had to go out and buy lots of fans.

Oh, but hang on that's burning more fossil fuels though, isn't it, by plugging all those fans in to the house all the time.

Now, unfortunately, the loss of ice reduces the size of habitats for polar animals like penguins, seals, and polar bears.

Of course, ice is going to melt if it's too hot, isn't it? The warmer temperatures are also melting sea ice, which is causing sea levels to rise, and flooding.

So if you are nearer areas that are on the sea, that sea level rising is going to be a big problem.

Many habitats are affected by climate change.

Habitats may become hot for animals to live in.

Changes in climate also affect how and where plants grow.

So animals may find it very hard to find food and to survive.

Here you can see soil all dried and cracked from excess heat.

Nothing else is really going to grow there is it? In fact, you can see where the grass was growing and how it's struggling to grow now where it is all cracked.

So let's stop and think.

What are fuels like coal, oil, and natural gas called? The correct answer here is fossil fuels.

How do greenhouse gases affect Earth's temperature? The correct answer here is, they trap heat from the sun, making Earth warmer.

So here's your first task.

Aisha, Jacob and Lucas are discussing greenhouse gases.

Here's the three of them here.

And Aisha says, "Oh, it would be better if there were no greenhouse gases around Earth at all." Jacob says, "We need to have some greenhouse gases around Earth, but not too many." And Lucas says, "We need more greenhouse gases around Earth." Hmm, who do you agree with and why? Discuss, good luck with your task.

So who do you agree with and why? Jacob here says, "We need to have some greenhouse gases around the Earth, but not too many." Well, Jacob is correct here.

Greenhouse gases trap the sun's heat, causing the Earth to get warmer.

Without these gases, the Earth would be too cold to live on.

However, when levels become too high, Earth becomes too hot.

So Jacob was correct in this case.

We need some gases around the Earth, but not too many.

Well done for that task.

The next part of this lesson is called sustainable ways of generating electricity.

Lucas here says, "We need electricity, so what will we do when the fossil fuels actually run out?" Aisha says, "Oh, we'll have to go back to using candles for lighting and fires for heating." Hmm, I'm not sure.

Do you know? What's gonna happen when the fossil fuels run out? Well, scientists and engineers investigate and develop alternative ways to generate electricity that are a lot less harmful to the environment than the things that we do now.

And remember, although we're saying that fossil fuels are going to run out, it doesn't mean that they're going to run out tomorrow.

We need to do things now in order to make sure that they don't run out for future generations.

So do you know of any alternative ways to generate electricity? Have a think.

Well, solar panels are just one way.

Maybe you mentioned these.

These convert sunlight into electricity.

Here you can see some buildings which have got solar panels on the roof.

Calculators, you may have some of these in your classroom, they can generate electricity using a solar panel so they don't run out of charge when they're sitting away in a tray for so long.

When you get them out, they're ready to be used again.

And of course, garden lights can convert sunlight into electricity so that they can light up at night, and these would need to power up a battery that's recharging in there underneath the solar panel.

So Lucas said, "Oh, I've seen wind turbines in fields." Oh, yes, of course, you may have some of these near you, especially if you live in a place where there's lots of hills.

Wind turbines use moving air to rotate their blades, the mechanisms inside work to generate electricity.

Now, this is not a windmill because it's not milling anything on the inside.

It's a wind turbine because a turbine is generating electricity for us.

As I said before, you'll find these in lots of places that there are hills, or maybe you can see them off of the coast of the country that you're in.

Electricity can also be generated by other methods.

Biomass is a name used for materials such as wood, crops, and algae, which are used to generate electricity.

Here you can see an example of some biomass, some wood there.

Now biomass can be burned like fossil fuels, in a biomass plant.

It can generate electricity and it can also go through processes to change it into a liquid fuel called biofuel.

This is then used in vehicles like petrol and diesel.

So there's the example of biomass, and of course a biomass plant as well.

You can see there, there's lots of storage tanks down the side of that building there, something for storing some of the liquid fuel that's been generated.

Electricity can also be generated from the heat that exists deep underground, methods using heat from the Earth to generate electricity are called geothermal.

Ah, yes, of course.

You may have seen some of these in the news before.

Naturally occurring hot water or steam from deep underground can be used to turn turbines in power plants to generate electricity.

So all of that steam is created from inside the Earth, and it's rising up through the cracks underneath the Earth to come out through the Earth's surface.

Now we can then use that rising steam to generate electricity as well, how fantastic.

The warmth of the Earth can be used to heat or cool water in buried pipes.

If you've ever gone into anywhere with some under-floor heating, you might realise how nice this is to feel, and it's great then that the Earth can help to generate this kind of heat as well.

Hydroelectricity is generated by the power of moving water.

The movement of the water is used to turn the turbines to generate electricity.

Here you can see water moving through a dam.

Now, dams are very interesting things because you need to be able to block a river first.

Here in America, you can see that a river has been blocked using the dam.

Now that makes the water build up on the opposite side of the dam.

When they want to allow the water through it then allows the river to continue, but not before going past all of the different turbines.

That helps to generate electricity.

Here as well you can see some waves generating electricity.

The movement in these large, long red buoys here are moving up and down and generating electricity.

There are little turbines in there that can help to generate electricity, sending it through a cable, back to the shore.

Now, these methods for generating electricity are called sustainable sources of electricity.

That's because they come from sources that don't need to be replaced because they're never going to be used up.

Such examples are the sun.

It's always going to keep on shining.

The wind will always keep on blowing, and the water will always keep on moving as well and causing waves.

So let's stop and think, true or false? In the context of climate change, burning fossil fuels is the best way to generate electricity.

The answer to this question is false.

Can you justify that answer? The best way to justify this is with a, there are alternative ways to generate electricity that can be less harmful to the environment than burning fossil fuels.

What is the name for sources of electricity that won't run out such as wind, hydropower, solar power, biomass, and geothermal? The correct answer here is b, sustainable sources.

Those are all examples of sustainable sources of making electricity.

So it's time for task B.

Jacob is making a matching game.

He's made a photo and some name cards for the different sustainable sources of electricity.

It's your task here to write a brief description to go with each source.

He's chosen solar sources, wind sources, geothermal sources, hydroelectric sources, and biomass sources, lots of different sources.

So write a brief description of each of those.

Best of luck with your task.

Restart the video when you've done that.

How did you get on? Well, your answers may look similar to some of these.

Here you can see the solar and the wind sources.

Solar panels convert sunlight into electricity and wind turbines use the moving air to rotate their blades.

The mechanisms inside work to generate electricity.

The biomass sources, the geothermal and the hydroelectric also work in different ways too.

Biomass materials like wood, crops and algae are burned to produce electricity or can be turned into fuel.

Geothermal electricity is generated using heat from the Earth, and hydroelectric sources mean generating electricity by using the power of moving water.

Now, some of your answers may have been phrased slightly differently, but I'm sure you were able to research and discover the different sources of electricity and the different ways in which they can be used.

Well done.

Let's summarise our lesson.

Traditionally, electricity is generated by burning fossil fuels, which produces greenhouse gases that trap heat from the sun.

There are alternative ways of generating electricity that can be less harmful to the environment.

Electricity can be produced from sustainable sources that won't run out, such as sunlight and wind.

Hydroelectricity is a sustainable source that's generated by the power of moving water.

Other sustainable sources of electricity are biomass and geothermal.

Well, there's lots of different knowledge that you could have picked up through that lesson.

Hopefully now you've got a good understanding of what fossil fuels are and also what different sustainable source of electricity are as well.

You can then go on to make your own decisions about how best to help our planet in the future, hopefully by using some of those more sustainable sources of electricity.

I've been Mr. Wilshire, thank you very much for listening.