Hello, my name's Mrs. Miton-Smithson.

I'm pleased that you've come along to learn with me today.

This lesson, we're going to look at the particle model of substances in the gas state.

If this sounds a little complicated, don't worry, we're going to go through this bit by bit.

It's part of the unit solid, liquid, gas states and changes of state.

By the end of today's lesson, you should be able to describe how the arrangement and movement of particles alters when a substance changes from the liquid to gas states.

Here are today's keywords.

Gas state, particle, random movement, compress.

On the next slide, you'll see some sentences that include these words.

You may pause the slide and read them if you wish.

So here's what we're going to do today.

This lesson on the particle model of substances in the gas state is made before learning cycles.

First, we're gonna do about the particle model of gas state.

Then we're going to look at the forces of attraction, followed by the properties of the substances in the gas state.

And then finally, we're going to compare the gas state to liquid and solid states.

Our first learning cycle is particle model of gas state.

Let's get going.

Substances can be classified as being in a solid state, a liquid state, or a gas state.

There are three states of matter.

Particles that make up these states of matter are too small to see with your eyes.

So here's the particles arranged you'll see in a regular pattern and they're touching.

This is in a solid state.

In a liquid state, you'll see the particles are still touching, but now they're random and they can move over each other.

And finally, in the gas state, this is the one that we're going to focus on during this lesson.

In a gas state, there's nothing at all between the particles.

There's just some empty space.

A lot of people think that there's air between the particles, but that would be wrong.

So you need to remember that there is just space, nothing between these particles, just empty space.

Now a check for understanding.

Which diagram shows particles in the gas state correctly? Is it A, is it B or is it C? Pause the video if you'd like some thinking time and press play when you're ready.

If you said B, well done, you're absolutely correct.

There's nothing but space between the particles.

These students have been discussing helium gas in a balloon.

Each one of them thinks that they have got the best description of the helium gas in a balloon.

I'd like you to think, who do you agree with the most? So Andeep says, "It is made of particles of helium with spaces in between them." Jacob said, "There are particles dotted about in the helium gas." Laura says, "It does not have any particles." Izzy said, "It is made of particles which are gassy, like tiny puffs of gas." Pause the video now.

Have a little think and then press play when you've got your answer.

Well done if you said Andeep.

Andeep definitely has the best description of helium gas.

So he said, "It's made up of particles of helium with spaces in between." He's absolutely right.

There is just space between the particles.

Here's an animation that shows the particles moving very quickly in random directions.

So this is what a gas state looks like.

In the previous diagrams, we didn't have any movement, but this is how they are.

You can see that they're moving very quickly and they're moving in random directions.

There's not a set direction that they move in.

They just move randomly.

In between the particles, so where there's black, that just represents space.

So there's nothing in between the particles.

Quick check now.

Which statement describes the movement of particles in a gas state? Do you think A, very quick in random directions.

B, very slow in random directions.

Or C, very quick in one direction.

Pause video now, have a think and press play when you're ready.

Well done if you said A, very quick in random directions.

The particles in the gas state do indeed move randomly and quickly in any direction.

Now we've got a task.

So ihelp Sofia to describe the movement and spacing of particles in a gas.

Sofia has been given three sentence starters by her teacher and each one of her friends have suggested three possible answers for a sentence.

What you need to do is match them up.

So Sofia has got these three sentence starters.

The particles move.

Between the particles there is.

And the particle speed is.

Izzy is suggesting only upwards, orderly downwards, randomly in all directions.

Sam is suggesting only air, only space or some gas.

Alex is suggesting fast, medium or slow.

Pause the video now and press play when you've got your answers.

Now we're going to have a look and see how well you've done.

So let's have a look.

The particles move randomly in all directions.

Between the particles, there is only space, nothing else, just space.

And the particle speed is fast.

We've now completed our section on particle model of gas state.

We're going to look at the forces of attraction in the gas state now.

We're going to look at forces of attraction in the gas state.

So the forces of attraction between the particles in the gas state.

So we've got very, very weak.

So they're at one end of this diagram here compared to the solid where they're very, very much stronger.

The particles in a gas state have got enough energy to be free of those attractive forces.

So they're not pulled together by those attractive forces 'cause they've got enough energy to overcome them and that means that they can move away from each other in any direction.

So if you remember, particles in a gas state are very, very weak.

They've got enough energy to be free of the attractive forces.

They can move away from each other in any direction.

True or false? There are no forces of attraction between the particles in the gas state.

Is that true or is that false? Then I want you to justify your answer.

Particles that have got enough energy can break free of the weak forces of attraction or the forces of attraction pull the particles together in the gas state.

Pause the video now if you'd like some thinking time.

Then press play.

So well done if you said that they are false.

There are no forces of attraction between the particles in the gas state and that means that A is also right.

They've got enough energy that they can break free of those weak forces of attraction and that allows 'em to move randomly in any direction.

Now we've got task B.

Aisha's completed her homework and she's got some of the facts incorrect.

What I'd like you to do is find the five errors in Aisha's homework and correct them.

So she's got three sentences.

The forces of repulsion between particles in the gas state are very, very strong.

Particles don't have enough energy to be free of the attractive forces between them.

Particles can move towards each other in any upwards direction.

So find the errors and correct them.

Pause the video whilst you do that and then press play when you're ready for the answers.

Okay, let's go through the answers now.

So the forces of attraction between particles and the gas state are very, very weak.

Particles have got enough energy to be free of the attractive forces between them and that means that particles can move away from each other in any direction.

So well done if you corrected those five errors in Aisha's homework.

Okay, we're doing really well with this lesson.

We've done particle models of gas state, forces of attraction in the gas state, and now we're going to move on to properties of substances in the gas state.

So we're going to look at how gases behave.

We said earlier that particles in the gas state are free to move in all directions and are not fixed to other particles.

This means that they can be poured, they can flow, they will fill the entire container and they will escape the container if the container's got no lid.

So here's a gas jar.

This is used in labs and in science classrooms. It's got a lid on it and the gas particles are enclosed.

However, if we take the lid off, you'll see that they start to escape.

Let's check to see how much you know.

So I want you to select two properties.

So two ways that a substance that's in the gas state can behave.

Will it stay at the bottom of a container or will it fill the container? Can you pour it from one container to another container or can you not pour it from one container to another container? Have a read through these answers.

Select two and then if you need some thinking time, pause the video and press play when you're ready.

So well done if you said that it will fill the container, so that's B, and you can pour it from one container to another container.

If you take a substance in the gas state, because there are spaces between the particles, you could compress it.

This means that you can make it take up less space than it has done before.

So if we have a look, most of the particles in the gas state are far away from each other.

That means that if you apply a force, you can move those particles closer together because there's gaps between them.

So where there's just space between those particles, you can move those particles closer together.

The gas would then take up less volume than it did before.

As you can see from this little demonstration, here's a syringe that's full of air.

The finger has been placed over one end of the syringe, so the tip of the syringe and somebody's trying to press that in from the other side.

So if you have a look, you can press this down and because you can move it, what you're actually doing is you're moving those particles closer together.

I've got a diagram here and you can see that the particles are further apart.

And then when you press that plunger down, because the tip is sealed, it means that they can't escape.

So those gas particles can't escape.

It means that it will be compressed.

So it will take up less space than before.

Let's check to see how much you understand the word compressed.

So substances in a gas state can be compressed.

What does compressed mean? Does it mean to take up the same space than before being compressed, to take up more space than before being compressed or to take up less space than before being compressed? Pause the video if you need some thinking time and press play when you're ready.

Let's see how well you did.

Well done.

If you said compressed means to take up less space than before being compressed, then you're absolutely right.

You can make those particles move closer together and take up less space.

I've got a check for understanding for you now.

True or false, the air between the particles of a substance in the gas state means it can be compressed.

Is that true or is that false? I want you to also give a reason.

So one of the reasons, A, is there's nothing but empty space between the particles in a gas state.

Or B, the particles in a gas state are always touching each other and can slide over each other.

What do you think? Pause the video if you'd like some thinking time and press play when you're ready.

How did you get on? If you said false, you're absolutely correct.

There's not air between the particles.

There's nothing but empty space.

So that means that A is the reason why that statement is incorrect.

Well done if you got that right.

We've now got task C.

So Sam and Andeep are talking about the properties of substances in the gas state.

What I want you to do is I want you to help Sam and Andeep link their ideas to the correct explanation of statement or statements.

So Sam said that they are fairly easy to compress.

Andeep said that they spread out to fill the whole space they are in.

Both of these statements are correct.

All of these statements are also correct, but you need to link the ideas to the correct explanation.

So most of the particles in the gas state have very weak forces of attraction, are far from each other so there are spaces between particles, move around rapidly in all directions.

Gas particles are arranged randomly.

So there might be more than one explanation that helps Andeep and Sam link their ideas.

Pause the video now and press play when you're ready with your answers.

That might have seemed a little tricky, but I'm sure you've done your best.

Let's have a look and see how you got on.

So Sam, fairly easy to compress.

They are far from each other and there are spaces between the particles and that means you can push those particles closer together.

Andeep, he said that they spread out to fill the whole area.

Now, Andeep's idea has got lots of explanations.

He's in fact got all four explanations.

So they've got very weak forces of attraction.

That means that they can spread out.

They're far from each other and there are spaces between them.

They move rapidly in all directions and the gas particles are arranged randomly.

So well done if you got all of those correct during this lesson, you've been working really hard.

We've covered particle models of gas state, forces of attraction in gases, properties of substances in the gas state, and now we're going to look at comparing the gas state to the liquid state.

We're gonna see what's the same and what's different about them.

Let's have a look at liquid state particles.

If you remember, the particles are touching and you can see that in the diagram here.

They're in a random arrangement, so they're not in a regular pattern.

Gas state particles, the particles are not touching.

So that's different from a liquid, but you can also see that they are in a random arrangement.

There's only three of them here, but they are random.

Let's have a look.

See if you can find the two true statements about particles.

So a liquid state particles touch each other.

Liquid state and gas state particles have got space between them.

Only gas state particles have got space between them.

So select the two correct statements.

If you need some thinking time, pause the video and press play when you've got your answer.

Well done if you said that liquid state particles touch each other and only gas state particles have got space between them.

Got a true or false for you now.

So the gas state has got a random arrangement of particles, but the liquid state does not.

Is that statement true or false? Then what I want you to do is look at the statements A and B.

I want you to select which one justifies if that statement is true or false.

So is it particles in the gas state do not have enough energy for particles to overcome the forces of attraction holding them together or particles in the liquid state and the gas state have got enough energy for particles to move past each other.

If you need some thinking time, pause the video and press play when you're ready for the answer.

Both particles in the liquid state and the gas state have got enough energy for particles to move past each other and that means that they can exist in a random arrangement.

Well done.

Substances in the liquid state cannot be compressed.

That means you can't make them take up any less space.

So if we have a look, we can see that the syringe has sucked up some water.

Then what we've done is we've melted the end of it and now we're trying to push that in to see if we can compress a liquid.

So if you have a look, you can see that the plunger is not going in and that means that liquids cannot be compressed.

So the plunger is being pushed in, but those particles, because they're already touching each other, cannot be made to get any closer together.

This is compared to gas.

So substances in the gas state can be compressed.

So a similar experiment.

We're going to fill the syringe with air and then what we're gonna do is we're gonna place our finger over the end to seal it and you can see that you can push the plunger down because you can move those gas state particles closer together.

You can make substances in the gas state compressed.

You can make them take up less space than they have done before.

Quick check for understanding.

Which state of matter can be compressed? Neither liquid state or a gas state, a liquid state or a gas state.

Just select one of these.

If you want some thinking time, press pause and then press play when you're ready.

Well done if you said gas state.

You're absolutely correct.

That is the state of matter that can be compressed.

This diagram here, it's talking about the movement.

You can see that the gas state is moving quicker, so it's got increasing movement of particles compared to the liquid state.

They are moving faster in the gas state than the liquid state.

If we have a little look, you can see that in the liquid state, they're free to move around and over each other, but they remain touching.

However, in the gas state, they're moving very quickly in random directions and there's spaces between them.

A quick check for understanding now.

I want you to select the two true statements about the particles.

So we've got four statements to choose from.

Particles in the liquid state and the gas state are free to move.

Particles in the liquid state and the gas state vibrate, but do not move around.

Particles in the gas state have got spaces between them and the particles move very quickly in random directions.

Particles in the gas state and the liquid state aren't touching other particles.

So which two of these statements do you think is correct? Pause the video now for some thinking time and press play when you're done.

Well done if you said A, particles in the liquid state and the gas state are free to move and C, particles in the gas state have got spaces between them and they move very quickly in random directions.

Now we've got the final task for today's lesson.

You've worked really hard so far, so let's keep going.

Fill in the gaps in the table.

So we've got a table here.

It's got liquid state and gas state in rows and we've got different properties.

So are the particles touching? How are they arranged? Spaces between the particles.

Can it be compressed? Movement in the particles.

I want you to complete the empty boxes.

Pause the video now and then press play when you want the answers.

Well done for completing the task.

Let's see how well you did.

So are the particles touching? In a gas state, no.

But in a liquid state, yes.

How are they arranged? They're randomly arranged in liquid state.

They are also randomly arranged in a gas state.

Are there spaces between the particles? Not in a liquid, but yes, definitely in a gas.

Can it be compressed? So can we make it take up less space than before? No in a liquid, yes for a gas.

How do the particles move? They're free to move around and over each other in a liquid, but they can move very quickly in random directions with spaces between them in a gas.

So have a look at your answers, see if they match up.

Well done if you got all those answers correct.

You've worked really hard this lesson.

Let's have a look now at the summary.

So in a gas state, a substance can flow.

It fills the whole of the container and can be compressed.

In a gas state, particles of a substance are moving very quickly in random directions with space between them.

In the gas state, particles have enough energy to be free of the attractive forces between them.

There is nothing at all between the particles in a gas, just space.

And here's your diagram that you need to remember from today's lesson.

Well done for working hard during this lesson.

I hope you know a lot more about the particle model of substances in the gas state.