Lesson video

- Hi everyone.

My name is Miss Hummel and together we'll be answering the question, what are stars and star constellations? In this lesson, we will discuss how stars including the sun were made? We will see how humans have investigated more about stars since the invention of telescopes.

And finally, we will learn about constellations.

Our lesson will follow this structure.

First, we will discuss some facts about the sun that we might not know already, then we will discuss how stars like the sun are formed.

We will then learn about constellations followed by some application knowledge.

We have some application questions to test our knowledge.

In this lesson, you will need an exercise book or paper a pencil or a pen, a colour pencil or a pen, and a ruler.

If you haven't got those things, pause the video now and go get them.

Here are our star words which are the most important words of our lesson.

I'm going to say them and ask you to repeat them after me.

When I point at myself, it will be my turn.

And when I point at you it will be your turn.

Stars.

Constellations.

Hydrogen.

Helium.

Sun.

Gravity.

Dwarf.

Red giant.

Nuclear fusion.

That was the hardest one there.

We'll begin in our lesson by discussing what the sun is, as well as sharing, just some interesting facts about it.

- [Narrator] The sun is a star one of trillions of stars in the universe.

The gravity of the sun keeps the planet orbiting around it.

The sun looks bigger and brighter than any other star, because it is closer to earth.

We can also see the moon as it reflects the sun's light.

The sun is so big that 1 million earths could fit inside it.

It is a giant burning ball of gas consisting mainly of hydrogen and helium, with temperatures inside reaching 15 million degrees Celsius.

The sun's light is so strong that it is dangerous to look directly at it.

This amazing energy makes life possible on earth.

- Let's start with some facts then.

So the sun is a star.

The sun is up.

It gives out heat and light and makes life possible on the earth.

What are the two things that it gives that make life possible on earth? Heat and light.

The heat and light from the sun is felt and seen on our earth.

Think about how far away the sun is and how much we can still feel it on a hot day.

The sun is much, much bigger than the earth.

In fact, it's 1,300,000 times bigger than the earth.

So imagine 1,300,000 little earths fitting inside the sun, that's how large the sun is.

Now, I would like to see how many of those facts you can still remember about the sun.

Write down three of the facts about the sun.

You can pause the video to complete the question and you can resume once you've finished.

Now to mark your work.

You may have written that the sun is a star.

You may have written that it gives that heat and light and makes life possible on earth.

You may have written that the heat and light from the sun is felt and seen on earth.

And you may have written that the sun is much, much bigger than the earth.

In fact, it's 1,300,000 times bigger than the earth.

Now, if you wrote something else that you heard in the video or which I mentioned, that's also okay.

Now that we know that the sun is a star, we may be wondering how are stars like the sun formed? We'll look at that now as the next part of our lesson.

Stars are balls of gas burning across space in the universe, but there are different types of star, and each star goes through a number of stages.

So to begin with, stars are balls of gas that is burning, that's good for us to know.

Before a star is created we can find dust and gas across space in large amounts.

We knew this, we knew that we can find dust in space.

Now over time, gravity pulls these bits of dust and gas together so that they form large clumps of dust and gas.

We've got dust and we've got gas and together they get clumped and joined together.

And that's because of gravity.

You're now going to pause the video to think about this.

What was it that pulls the clouds of dust and gas together? I did just say it.

You can resume the video once you've thought of the answer.

You should have been thinking of gravity.

As more and more dust and gas is pulled in, this ball of dust and gas begins to get very hot indeed.

Just imagine how hot it's getting inside this star.

Eventually, when it is hot enough the ball ignites in a process that we call nuclear fusion.

Let's have a go at saying that sentence together.

Eventually, when it is hot enough the ball ignites in a process called nuclear fusion.

This is because of the combination of the elements and the gases inside of it.

It shines brightly and it gives off heat and it has become a star.

So what process did it need to go through for it to become a star? It needed to go through nuclear fusion.

You're now going to pause the video to remember what the process that is happening inside of a star is called.

We did just go through it.

To continue for a very, very long time, the star uses up the hydrogen that it has inside to keep shining and giving off heat and light.

And that's what our sun is doing at the moment.

Like you can see in the diagram, at the moment, 3/4 of the sun mass is made up of hydrogen.

Eventually, after billions of years, it runs out of hydrogen and begins to use helium.

So it was using hydrogen, which the sun for example right now is 3/4 hydrogen, but eventually it runs a out of that and it starts to use the helium.

This makes it become much, much larger in size and it changes colour as well, so it becomes what we call a red giant star.

Now you may be thinking that our sun looks a bit red already, but it's not a red giant star yet.

This will only occur in approximately 5 billion years.

We're now going to pause the video to think about this question.

What do we call the star when it uses helium and grows in size? You should have thought of the answer, a red giant star.

After a while longer, it will run out of helium as well.

So initially, it runs out of hydrogen, then it uses up its helium, becomes a red giant star, but eventually it will run out of that helium as well.

This makes the star collapse and release a lot of material, which may later form rocks, dust, planets and stars of the future.

So when it runs out of helium and it's already run out of hydrogen, the star will collapse.

More stars could be formed in the future, because the remaining heat of the stars collapse.

So when the star collapses, it produces a lot of heat, it's spread out.

That remaining heat could bring more dust and more gas together, which in future could form more stars.

Now all of this process leaves behind a glowing core that slowly cools down and eventually disappears.

You're now going to pause the video to think about this question, what's left behind of a star like our sun? And while you're thinking of that question I would also be thinking about whatever it's leaving behind, what can that create? Now you could have thought of the answer, which is it leaves behind a lot of material, which includes kind of rocks and dust, and eventually, this could form more planets and stars in the future.

You're now going to pause the video to complete a storyboard, to show the stages of the sun's life.

Setting out some information in this way really helps me remember.

So I hope it helps you remember as well.

You could create a table with six sections with enough space in each of the sections so that you have enough space for the description, but also for a brief sketch or a drawing to help us remember.

I would like you now to pause the video to complete that storyboard.

If you think you're going to need some help I'm going to model now how I would set it out.

So I'm going to start by drawing my grid.

I've already drawn mine.

I decided I wanted do 10 lines kind of width and 10 lines, I guess, height.

And then, I drew my six squares and now we are ready to start writing.

So I'm first going to write my first statement which is, dust and gas gather together.

I'm going to write, just a little number 1 next to it, I think.

Then for number 2, I'm going to write, gravity pulls the dust and gas into a hot bowl.

And I'm just going to really speed through these next few ones.

And I'm just quickly going to go through them.

So, dust and gas gather together.

Gravity pulls the dust and gas into a hot bowl.

It gets so hot that it ignites.

The sun uses hydrogen as fuel and shines white light.

The star gets bigger and becomes a red giant and the star collapses and sends out its material to area around it.

And I'm going to decide what to draw for it.

Now for dust, I can just draw it as little dots to begin with, to represent my dust.

And then to draw my gases, I might decide to, I could draw it like, I guess, like steam coming off of something, this is very difficult to draw a gas.

I can just draw it like steam coming off of something.

Then for my next one, I want to again, draw my dust and my gas, but I also want to draw gravity here, so I'm going to draw my dust first and my gas.

And then, I'm going to just make sure that I show that it's kind of in a circle and gravity's pulling it together.

I'm gonna draw some arrows to help me out and to write gravity there as well.

Then it gets so hot that it ignites.

I'm trying to think of how to draw that.

I think I could draw maybe a little explosion, like it's igniting.

Oh yeah, draw some lines here to make it look like it's very, very hot then for the sun uses hydrogen as fuel and shines white light.

I need to make sure that it makes sense kind of with everything else.

And I think I'll draw the sun first kind of as a circle and then I can draw hydrogen inside of it.

Maybe just another one, just so it's really clear that it's filled with hydrogen, and then I'm going to draw kind of that white light, I might even write white light on there.

So I'm really clear on what that is.

And then, I'm gonna leave the last two for you guys to do.

Now, pause the video to complete your storyboard.

You can resume once you've finished.

Let's watch a video about stars.

So the Greeks and the Romans that studied stars group them in something we call constellations.

Your turn.

Constellations are stars that you joined together in your mind to look like a shape.

Have you heard of any constellations before? The constellation Orion includes a series of stars which create kind of a rough shape of a hunter holding a bow and arrows.

Sometimes it does take a bit of imagination to see the shapes, but it has helped people map out different stars across the sky.

It's almost like those games where you connect the dots to see a shape or a drawing.

That's basically, what people have been doing with stars, they've been looking at the stars and in their heads using their imagination.

They've joined those dots to see what it would look like.

We've got a picture here of Orion, which they say looks like a hunter holding a bow and arrows.

Can you see the hunter holding the bow and arrows? I can see it, but I'm going to have to use my imagination to kind of put it all together.

As telescopes were created, and we were able to see the stars more closely, we have found that there are actually a range of stars, that means there's more than one type of star.

Very large stars tend to be called either blue giants or red giants.

Stars that are more red are not as hot on the outside.

And stars that are closer to blue are the hottest ones, and they're brighter as well.

Now it may be hard for you to imagine that, because when what we associate red, yellow and orange with heat more than we do with the colour blue.

In fact, when I think of the colour blue, I think of water, so I think of kind of cold.

However, there are blue flames and perhaps if you've got a gas hob at home or you've had a gas hob before, you've seen a blue flame.

If you haven't, I'm going to show you in a second.

But remember that none of you should be operating a gas hob without your parent or carer or helping you.

There are also stars called dwarf stars that are much smaller and do not burn as brightly.

They can be yellow, orange, red, and brown, depending on how hot they are and how much light they give off.

What are the colours again? Yellow, orange, red, and brown.

Finally, we will complete some application questions to help us apply our knowledge.

I would now like you to pause the video to complete this task.

Read the descriptions of the constellations below and work out which constellation is shown in the pictures.

We're going to say that they're A, B and C.

First we've got Centaurus.

It's a constellation that was named after a mythical creature that was supposedly half horse and half human.

We've also got Canis major, which means big dog which is said to be a dog following a hunter.

And lastly, we've got Draco or Draco which is Latin for dragon.

This constellation is a little bit like a snake, a little bit like a dragon.

Now that you know what we're looking for, look at the three pictures and you can resume once you finished answering the question.

Now get ready to check your answers.

So the one on the left was Draco or Draco.

The one in the middle was Centaurus the half human, half horse.

And the one on the right was Canis major, which meant big dog.

I would now like you to pause the video to answer this next task.

Read the statements below and decide if they are true or false.

Telescopes helped us see stars in more detail.

Is that true or is that false? Constellations are where animals and humans have gone into space.

Again, is that true or is that false? Sometimes you need to use your imagination a bit to see constellations, true or false? Stars that are closer to red in colour are hotter than stars that are more blue.

We should all know this one.

Is that true or is that false? And you can only get dwarf stars in one colour.

Is that true or is that false? You can resume once you're finished answering the questions.

Get ready to check your work with a different coloured pen or pencil.

Telescopes help to see stars in more detail, that is true.

Constellations are where animals and humans have gone into space, that's false.

Sometimes you need to use your imagination a bit to see constellations, that is true.

Stars that are closer to red in colour are hotter than stars that are more blue, that's false, like we saw with the hob.

You can only get dwarf stars in one colour, that is also false.

They can come in yellow, orange, red, and brown.

And that's it, great.

As our final question, which is a thinking task, I would like you to pause the video, to think about it.

Why did humans need telescopes to be able to study stars in more detail? Now, hopefully you're thinking of the fact that when we look at stars without telescopes, they just look like little dots in the sky and telescopes can zoom in, in a way which our human eye just can't do.

We have now finished our lesson and it is time for you to complete your exit quiz.

You need to exit the video and complete the quiz to test your knowledge and understanding of this question.

I hope you enjoyed the lesson, bye!.