Lesson video

Hi everybody.

It's Miss Simkin, back again for your next science lesson.

I hope that you are well and you're having a good day and you are excited to begin our lesson, which is all about the universe today.

So let us get started.

Our lesson question today is how have our ideas about the universe changed over time? And this is our lesson agenda for today.

We are going to start with our star words.

Then we're going to look at something called the geocentric model, then the heliocentric model, then we're going to look at elliptical paths and then we're going to do our exit quiz.

Don't worry if that all sounds a bit bananas and in another language, because it will all make sense when we get there.

For this lesson, you are going to need a piece of paper.

In fact, you're probably going to need a couple pieces of paper today.

We've got some big models to draw.

We're going to do two, and each will probably need a piece of paper.

You're going to need a pencil, some different coloured pencils today would be really good, and a ruler.

If you don't have those things, could you pause the video and go and get them now, please? Great.

Let's start with our star words.

I'm going to say them.

And then you're going to say them.

Universe.

Model.

Orbit.

Sun.

Planets.

Great, okay.

Let's talk about what these star words mean.

I'm sure that lots of them you are familiar with.

So the universe is the Earth and everything in space, so planets, moons, et cetera.

A model is a representation of something.

So we often use models in science to show something.

So for example, if I wanted to show you a model of how the Earth orbits the Sun, then I might use physical objects to model that.

Okay, it's a representation of something.

It's normally a lot smaller than the real thing.

We can also use drawings, or we can act things out as part of a model.

That brings us to orbit, which is the curved path that something takes.

So for example, you could imagine that this is our Sun and we know that the Earth orbits the Sun.

It's the curved path.

It goes around in a curved orbit.

Can you get your hand out now and make it orbit, please? Great.

The Sun is a star around which our Earth orbits, and the planets are celestial bodies in the universe that orbit our Sun.

Now we are going to learn about some different models of the universe today.

And the first model that we're going to learn about is called the geocentric model.

Can you say that? Geocentric model.

Great.

And the geocentric model was thought up by this astronomer, Claudius Ptolemy.

The P is silent in his name.

Can you say that with me? Claudius Ptolemy.

Good job.

Now, he was born in Egypt in 100 AD when Egypt was part of the Roman Empire, and he was a mathematician, a geographer, and an astronomer.

And he took the work of all the astronomers in the 800 years before him, and he studied it really carefully, and he made his own observations and kind of built on the work that they had done and used his excellent mathematical skills to develop his own model of the universe, and that was called the geocentric model.

And I'm going to show you what his model of the universe looks like.

So the most important feature of Ptolemy's model was that the Earth was at the centre of the universe.

That's why it's called the geocentric.

Geo stands for Earth, and centric means in the centre.

Geocentric, 'cause the Earth is where? In the centre.

Brilliant.

He then believed that the Moon was orbiting the Earth in the closest sphere to Earth.

Then, in the next, kind of the next closest orbit, he thought was Mercury.

So you can see the black line is the orbit.

Then he thought it was Venus.

Then the Sun.

Then the other planets.

So Mars, then Jupiter, and then Saturn.

So can you get your finger and put it on the Earth? And we're just going to go through each one again.

So he thought it was the Earth first, then he thought it was the Moon, so move your finger to the Moon.

Then he thought it was Mercury.

Then, can you remember what came after Mercury? Venus.

Then it was the Sun.

Then we should be on the pink one now, Mars.

Then Jupiter, then Saturn.

Okay, and he thought all of those, everything was orbiting the Earth in these circular orbits.

I've got a key on the side to help us remember the order of those planets as well.

And what I would like you to do now is to have a go at drawing this geocentric model of the universe.

So I would take a whole piece of paper so you've got lots of space.

I would definitely start in the centre, start with your Earth, and then draw each ring with the new planet or Sun or Moon or whatever it is on the outside each time.

Now, I would also suggest adding a key, like I've done, and you can use different colours for each of the planets.

You might also want to use a different colour for the Moon and for the Sun and for the Earth, if you don't want to draw it in a way that it's obvious that it's the Earth.

I would like you to be careful and take your time over this, so that you have a neat model.

You might even want to do a quick draught version first to see how you're going to fit everything and then draw up a neater version, okay? But take your time.

There's no need to rush.

Pause the video and take all of the time that you need.

Great, good job.

Okay.

Now this geocentric model was what? Was believed by scientists, astronomers and people on Earth for a very long time, until a scientist proposed a new model called the heliocentric model.

And this new model was proposed by a scientist called Nicholas Copernicus, in 1473.

So it was almost 2,000 years before a new model of the universe was proposed.

And it took even longer for people to agree with Nicholas Copernicus.

So with his new model of the universe, proposed by this Polish astronomer, he proposed that the Sun was at the centre.

So the word here, helio, that prefix, is Greek for Sun.

So it's like Sun-centric.

What was the other one? It was geocentric, yeah.

So now we're looking at the heliocentric model, because the Sun is in the middle.

So he believed that the Sun and not the Earth was in the middle, at the centre of our Solar System.

And he thought that then the planet was Mercury, then Venus and then, the Earth orbited the Sun, just like the other planets.

And the Moon orbited the Earth.

So that's a big difference.

Where was the Moon in the last model that we looked at? If you can't remember, take a look at your drawing.

Yeah, the Moon was in orbit around the Earth.

And then the planets continue to orbit like this.

Okay, and there's the key.

Now, what are the two main differences then between this model, the heliocentric model and the geocentric model? Can you say it to your screen? Great.

So in this, we have the Sun in the centre, that's one of the main differences, not the Earth.

And then the second big difference is that the Moon is orbiting the Earth.

Can you now pause the video and draw this model? So I would start a new piece of paper and do the same that you did last time.

Start from the middle, go slowly out, and then include a key as well, so you can tell what each planet is.

Pause the video and do that for me now.

Great.

Next we're going to look at elliptical paths.

The next scientist we're going to learn about is this one, Johannes Kepler, who was born in 1571 in Germany.

Now he investigated mathematical patterns and data and he made and he tested hypotheses until he developed an even better understanding of the arrangement and the movement of our Solar System than any other scientist who'd gone before him.

And his big discovery was that the Earth and the other planets did not orbit in a circular path, but they orbited in an elliptical path.

So an elliptical path is like an oval.

So he agreed with the heliocentric model, where the Sun is in the centre, but his big difference was that the orbits were not circular, they were elliptical.

How have our ideas about the universe changed over time? I would like you, please, to answer this question.

I would like you to write a paragraph for your answer here.

So not just one sentence.

We've learned about three different ideas of the universe.

So you've got lots to write about.

You need to write with the first model of the universe that we learned about, then the second model, and then the third model.

To help you, you can use your drawings of the models, and I've also got a word bank here for you.

Can you please pause the video and have a go at answering this question, thinking about your learning from the whole lesson.

Pause the video and have it go for me now, please.

Great, good job.

I hope that you are really proud of the work that you've completed today.

You've got two whole models of the universe that you've drawn and a great written explanation.

Well done.

I hope you're really proud of yourself.

If you would like to share your work with Oak National, then you can do that by asking your parent or carer to share your work on social media, and tagging @OakNational #LearnwithOak.

You can also tag @Teach_STEMinism, and then I'll be able to see it too.

You can share any of your work that you've done throughout this unit that you're proud of, and I would love to see it.

Don't forget to do your end of lesson quiz, just before you go.

Thank you for working so hard today.

I hope that you've enjoyed these history of science lessons as much as I have.

Have a fantastic rest of your day, and hopefully I will see you back on Oak National for another science lesson soon.

Bye everybody.