Lesson video

Hi everyone, my name is Miss Hummel and together we'll be answering the question, what is the universe and what is it made from? In this lesson, we will investigate what the universe is, we will also discuss galaxies including the galaxy we're in, which is the Milky Way.

Finally, we'll discuss and investigate the Big Bang Theory as an explanation for how the universe began.

our lesson will follow this structure.

First, we will discuss what the universe is, then we will speak about galaxies and The Milky Way, we will follow that with a discussion of how the universe began and what scientists think happened.

Finally, we will end with an investigation.

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

If you haven't got those things pause the video now and make sure you 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.

When I point at you, it will be your turn.

Stars.

Galaxy.

Universe.

Expanding.

Milky Way.

Billion.

Big Bang Theory.

Right, we will begin by discussing what a universe is.

Although we use that term loosely to say things like, "Oh it's the best thing in the whole universe," not many people consider what a universe actually means.

We're now going to take part in an imagination activity.

First, imagine a tiny grain of sand.

Now imagine all the grains of sand that you could fit into a cup of sand.

Now imagine all the grains of sand that you could fit onto a whole beach.

Try and imagine all the grains of sand that exist on Earth.

Now that we've kind of begun to imagine it, just so you're aware, there are even more stars than there are grains of sand on the Earth.

There are still so many stars that we're just trying to figure out.

Now, repeat after me, the universe can be defined as the collection of all the stars, planets, rocks and dust that can be found in space.

The universe can be defined as the collection of all the stars, planets, rocks and dust that can be found in space.

This includes all living things and all matter that exists and that has ever existed.

Now it is your turn to answer this question.

What is the universe? The universe is the collection of.

We've spoken about the solar system being the collection of celestial bodies around the sun but there are billions more stars across the universe and most if not all of those stars will also have their own planets orbiting them.

So we're orbiting the sun, which is a star already but there are loads, billions of stars that are like the sun which might also have planets around them.

Even if I wanted to, I could not show you a billion more solar systems on this screen.

Now, let's discuss what we mean by a galaxy and by something that you've probably heard of which is the Milky Way.

And no, we don't mean chocolate.

Stars are sometimes found on their own in space.

However, at least half of all stars are clumped together in groups that we call galaxies.

Repeat after me, a galaxy is a group of stars held together by gravity.

A galaxy is a group of stars held together by gravity.

You're now going to pause the video to complete this thinking task.

What is a galaxy? How is a galaxy different from the universe? You can resume the video once you've finished thinking about those questions.

Now, a galaxy is a group of stars held together by gravity while the universe is the collection of all stars, planets, rocks and dust that exist and have ever existed.

There are lots of galaxies in the universe.

We're in a galaxy called the Milky Way.

This is a group of stars, that is about 250 billion in a giant disc shape kind of like what you can see in this picture.

This means that we are one solar system in one galaxy out of billions of solar systems within our galaxy.

And our galaxy is one galaxy out of billions of galaxies in the universe.

So if I were to set it up, we're on Earth which is one planet in our solar system.

There are billions of solar system in our galaxy, which is the Milky Way.

There are billions of galaxies in the universe.

On a very clear night in the countryside, if we can see a streak across the sky that is brighter than the rest, this is some of the Milky Way.

You can see it in our picture and you can see it behind me.

You're now going to pause the video to complete this recap task.

What is the name of the galaxy that we are in? That should be a quick one.

Now scientists don't know exactly how many galaxies there are.

It's said it's billions.

It's lots and lots and lots.

However, they have estimated it could be a number called a billion trillion.

You can see how many zeros that is on the screen.

So imagine our galaxy times a billion trillion.

You're now going to pause the video to complete this match up task about the different objects that are in the universe.

On the left-hand side we have the terms, star, planet, galaxy, and universe.

And on the right-hand side, we've got our definitions so we've got a spherical object that orbits a star, all the stars, planets, rocks, and dust in space, a very hot ball of gas where nuclear fusion happens, a group of stars held together by gravity.

So pause the video now, complete the task and you can resume the video, once you're finished with this activity.

Now get ready to mark your work.

So, a star went with a very hot ball of gas where nuclear fusion happens.

A planet is a spherical object that orbits a star.

A galaxy is a group of stars held together by gravity and the universe is all the stars, planets, rocks and dust in space.

Now for the question we've all been waiting for.

How did the universe start? When scientists, about a 100 years ago began to observe galaxies that are really far away from the Earth, they made a very interesting discovery.

What is it that we can see in our picture which has helped scientists observe the galaxies? Now everywhere they looked, the galaxies were moving away from each other.

The further away they were, the faster the galaxies were moving.

So they made a conclusion and they thought, well, this must therefore mean that the universe is expanding because they could see all these galaxies but they could see that they were moving further and further and further away, which made them think that if the universe was like this, it's now expanding and making them be further away.

You're now going to pause the video to complete this recap task.

What do scientists see happening to galaxies across the universe? Another group of scientists noticed that space, was not completely cold.

In fact, every part of space seemed to have some sort of heat in it as if there was an explosion that happened a long time ago and the heat was left over kind of like when a star collapses, it releases a lot of heat, they thought there must be some heat from something.

These two things led scientists to come up with a theory called the Big Bang Theory.

Now repeat after me, this theory suggests that all matter that ever existed began in a single point that suddenly exploded outwards.

Now, how can we remember this? So all matter that ever existed began in a single point that suddenly exploded outwards.

See if you can remember that definition.

Now to recap, what is the Big Bang Theory? See if you can use our actions to help you remember.

You're now going to pause the video to sketch some diagrams to show the evidence that scientists use for the Big Bang Theory.

So we've first got, all galaxies appear to be moving away from each other, so they must have been a big explosion in the past that made them do this and everywhere scientists look, there's some leftover heat from a big explosion that happened a lot of time ago.

So pause the video now to sketch your diagrams for those two pieces of evidence that scientists use to try to prove the Big Bang Theory.

Now you're going to watch me demonstrate something about the Big Bang Theory.

Let's imagine that this balloon is our universe and how it all began.

So small little spot.

Now in our universe, we know that we've got lots of different galaxies.

So I'm going to draw just a few, remember that there are billions and billions and billions but I'm just going to draw a few.

So I'm going to draw one, can't really see.

I'm going to draw one here which I'm going to put an E next to, because I want to say that that's the galaxy that the Earth is in.

Another one over there here.

Let's put a few on the other side.

Okay, so have a look at the balloon now.

So we've got a little section that has an E.

We're going to say that's the galaxy that Earth is in, so the Milky Way, and then we've got some other galaxies.

I can't draw a billion dots.

So I'm just going to draw a few.

So if this is how our universe began, then it would have just all been in one point.

And then as an explosion happened, it would have began to kind of expand and spread further away.

So when I do that there, you can see that further away, there's not, you can see that further away, there's not many galaxies just yet, but that they're all kind of still bunged together over here.

They are getting further away from each other though.

And as it gets larger, they are getting further and further away, those galaxies.

As it's getting even larger, the distance between some of the galaxies is now getting really large like you can see, sorry, it's hard for you to see.

Now they're getting a little harder to see but they're so far away from each other, now that they've continued to kind of expand.

So we need to imagine that this balloon is basically like our universe.

And there were all these galaxies that were all together and now they've just been expanding and spreading and getting further and further away because there was some sort of explosion that meant they're getting further and further away.

Hopefully the balloon demonstrated that.

Now I don't think any of you would be happy that I popped this balloon.

Oh, I'm scared.

That was so loud.

Now I'd like you to pause the video to read these statements below and answer these questions about my investigation.

So what did the balloon represent? The balloon represents.

Number two, what happen to the galaxies as you go forwards in time? Number three, what does this mean about the universe? The universe must be.

You can resume once you've finished answering those questions.

Now to mark our work, the balloon represented the universe especially when it began.

As you go forwards in time, the galaxy spread further and further away like my balloon expanding.

What does this mean about the universe? Well, it means that the universe must be expanding which supports the Big Bang Theory, because if all of these galaxies are just getting further and further away from each other, not even just from our galaxy but from other galaxies as well, then it must mean that our universe is just expanding.

To end the lesson, I would like to pause this video to take part in this thinking task.

The Big Bang Theory is quite a new theory, Why do you think that some people are not so sure if it's definitely right yet? Now think about it.

Is there actually a way of us knowing what happened to begin the universe, if we can't observe it and we weren't there? There is some evidence we can base it on, but at this point, it's still a little bit of a guessing game.

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 lesson.

I hope you enjoyed the lesson, bye.