Lesson video

Hello, and welcome to today's lesson.

I am Mrs. Adcock, and today, we are going to be learning about the particle model.

How can we use the particle model to explain the properties of solids, liquids, and gases? Today's lesson outcome is: I can describe the particle model of matter and how it explains the properties of solids, liquids, and gases.

Here, you can see some of the keywords written in a sentence that we will be using during today's lesson.

The keywords are states of matter, particle model, forces of attraction, and compress.

It would be a good idea to pause the video now and read through those sentences.

You might even like to make some notes so that you can refer back to them later in the lesson if needed.

Today's lesson on the particle model is split into two main parts.

First of all, we are going to focus on three states of matter.

Then we are going to move on to look at the properties of these states of matter.

Let's get started on the first part of our lesson, three states of matter.

All substances are made of matter.

Substances commonly exist in one of three states of matter.

These states of matter are the solid state, the liquid state, and the gas state.

In the images, we can see water that is present in each of these states of matter.

So here we have water present in the solid state and you can see ice cubes in the image.

Here we have water present in the liquid state.

And finally, we have water present in the gas state.

Hopefully, you can see the water present in the gas state in the image rising out of the beaker and from the kettle.

Let's have a look at the particle model.

The particle model is used to represent matter in different states.

The particle model uses small solid spheres to represent particles in these different states.

The diagrams below show how each state of matter is represented using the particle model.

Here we can see the particle model used to represent the solid state.

And hopefully, you'll notice that those particles are arranged in a regular pattern in the solid state.

Here in the image, we can see the particle model used to represent the liquid state.

And the particles, which are those small solid spheres, are now arranged in an irregular pattern.

Here in this final image, we can see how matter is arranged in the gas state.

We can see the particles are in an irregular arrangement and the particles are spread out in the gas state.

In a solid or liquid state, particles in a substance are held together by forces of attraction.

Here we can see the particles arranged in the solid state and these arrows represent the forces of attraction that hold those particles together.

These forces of attraction act in all directions and they vary in strength depending on the substance and its state.

Here we can see the irregular arrangement of particles in the liquid state and we've used arrows to show the forces of attraction.

Hopefully, you can notice that those forces of attraction that hold the particles together are acting in all directions.

As particles gain energy, they are able to overcome the forces of attraction between them.

Forces of attraction between particles vary in strength depending on the substance.

Here we can see the particle model showing particles arranged in the solid state.

Here we have the particles arranged in the liquid state, and here we can see the arrangement of particles in the gaseous state.

If particles in the solid state gain energy, then they can overcome those forces of attraction that are holding the particles together and the substance can change from the solid state to the liquid state.

We can have another change of state if we increase the energy of those particles in the liquid state.

Again, they can overcome those forces of attraction and the substance will change from the liquid state to the gaseous state.

So as we move from the solid state to the liquid state, to the gas state, the particles have got increasing energy.

Time for a check for understanding.

The three states of matter that matter commonly exist in are.

A, elements, particles and atoms. B, solid, liquid, and gas.

C, melting, freezing, and boiling.

The correct answer is B, so well done if you got that question correct.

The three states of matter that matter commonly exists in are solid, liquid, and gas.

Particles in the solid state do not have enough energy to overcome the forces of attraction between them.

Those particles exist in a regular arrangement.

The particles are kept in a fixed position by those forces of attraction.

The particles can vibrate around their fixed position, but the particles cannot move freely in the solid state.

Here you can see we have a model that shows us the particles in the solid state.

The particles are in a regular arrangement.

They are kept in their fixed positions by those forces of attraction, but they can vibrate around their fixed position.

Here in this model, we can see the particles in the liquid state.

These particles have enough energy to partially overcome the forces of attraction between them.

The particles in the liquid state are randomly arranged.

The particles are kept close together by forces of attraction.

But unlike the particles in a solid, the particles in a liquid can move past neighbouring particles.

In this model, you can see the particles in the gas state.

These particles have enough energy to completely overcome the forces of attraction between them.

The particles in the gas state are randomly arranged and they have empty spaces between them and the particles move quickly in all directions.

Time for a question.

Is this statement true or false? In all states of matter, the particles are free to move past other particles.

That statement is false.

Can you justify your answer and explain why that statement is false? Is it A, only in the gas and liquid states are particles free to move past each other.

Or B, only in the gas state are particles free to move past each other.

Hopefully, you got that question correct and chose answer A.

In the gas and liquid states, the particles are free to move past each other, but they cannot move past each other in the solid state.

In the solid state, the particles vibrate in their fixed positions.

Let's have a go at this question too.

Forces of attraction between particles are.

A, the same strength for all substances.

B, different strengths for different substances.

C, overcome when changing from liquid to solid state.

D, overcome when changing from liquid to gas state.

Choose any answers that you think are correct.

Forces of attraction between particles are different strengths for different substances, so answer B, and also forces of attraction between particles are overcome when changing from the liquid to gas state.

So well done if you chose both answers B and D.

Time for us to complete our first practise task of today's lesson.

And for this task, you need to sort the following statements into the correct columns in the table.

Here you can see those statements and you need to decide whether they go into the column for solid state only, solid and liquid state, liquid state only, liquid and gas state, or the gas state only.

Pause the video now, read through those statements carefully and decide which column in the table they go into.

I'll see you in a moment when you're ready to go over the answers.

Let's see how you got on.

Particles touching refers to the particles in both the solid state and liquid state.

The particles are not touching.

That would be the gas state only.

A regular arrangement of particles refers to particles in the solid state only.

A random arrangement of particles refers to particles in both the liquid and gas state.

Particles vibrate in a fixed position should be in the column for solid state only.

The particles are free to move past each other whilst touching other particles refers to particles in the liquid state only.

Particles move very quickly in random directions should be in the column for gas state only.

No spaces between the particles is the solid and liquid state.

Spaces between particles is the gas state only.

Cannot be compressed refers to particles in the solid and liquid state.

And particles can be compressed in the gas state only.

Well done if you placed all of those statements into the correct columns.

We have had a look at how particles are arranged in those three states of matter, the solid state, the liquid state, and the gas state.

Now we are going to move on to look at the properties of those different states of matter.

Can the state of matter flow and take the shape of its container? Here we have a table which shows us those three states of matter, solid, liquid and gas, and we are going to look at whether those states of matter can take the shape of their container and explain why they can or cannot.

So solid do not take the shape of the container and this is because the particles are held in a fixed position by those forces of attraction.

In the liquid state, they can take the shape of the container and we will see the liquid present at the bottom of a container that it is placed in.

In the image there, you can see we have some oil in the liquid state and the oil has filled the bottom of the container that it is placed in.

There is no oil present at the top of the container, but it has filled the bottom of the container.

This is because in the liquid state, the particles are free to move past each other and fill the shape of the container.

In the gas state, the particles can also take the shape of the whole container.

In the image there on the right-hand side, you can see we have bromine gas and the bromine gas is an orangy brown colour, and the bromine gas has taken the shape of the whole flask that it is placed in.

This is because the particles in the gas state can move very quickly in all directions and therefore they can spread out and take the shape of the container.

Let's have a go at a question.

Particles can flow past each other and take the shape of the bottom of the container or the whole of the container in.

A, the gas state only.

B, the liquid state only.

C, the liquid or the gas state.

D, all the states of matter.

The correct answer is C, particles can flow past each other and take the shape of the bottom of the container in the liquid state, or they can take the shape of the whole container in the gas state.

So well done if you chose answer C.

You cannot compress a substance in the solid state.

And when we talk about compress, we mean whether it can be made to take up less space, so a solid cannot be made to take up any less space and this is because the particles are already touching.

They have no space between them and they cannot be forced closer together.

Here in the image, we can see the particle model has been used to show the particles in the solid state and you can see those particles that are in a regular arrangement are already touching.

In the animation here, we can see that we have a syringe filled with sand in the solid state and someone is trying to compress this substance, but you cannot compress a substance in the solid state.

You cannot compress a substance in the liquid state.

It cannot be made to take up any less space and that's because the particles are already touching in the liquid state.

They have no space between them, and therefore, the particles cannot be forced closer together.

In the image here, we can see the particle model showing the particles arranged in the liquid state.

The particles are arranged in an irregular arrangement and you can see that the particles are already touching, so we cannot force those particles closer together.

Here in the animation, you can see we have water present in a sealed syringe.

The water is present in the liquid state and someone is trying to compress the water in the syringe, but the water which is in the liquid state cannot be compressed and that's because those particles are already touching and there's no space between them.

You can compress a substance in the gas state to make it take up less space and this is because most of the particles are far apart in the gas state.

There is space between the particles, so there was no space between the particles in the solid and liquid state, but in the gas state, there is space between the particles.

Therefore, we can apply a force to move those particles closer together.

When we do this, the gas takes up less volume than it did before.

Here in the animation, you can see we have air in the gas state present inside that closed syringe.

And this time when someone applies a force, they are able to compress the substance in the syringe.

Here in the top image, you can see the air particles present in the syringe.

And when a force is applied, then those particles can be forced closer together, so we have the same number of particles in the bottom image, but the particles have been forced closer together.

The gas state can be compressed so that the gas takes up less space.

Time for a question.

Substances can be compressed.

A, in the gas state only.

B, in the liquid state and the gas state.

C, in the liquid state only.

The correct answer is A, substances can be compressed in the gas state only.

We cannot compress substances in the solid or liquid state.

Let's just summarise what we have learned about compressing substances in the solid, liquid, and gas state.

When we have matter present in the solid state, can it be compressed? No.

Why is that? Because the particles are already touching, so cannot be brought closer together.

Can we compress matter in the liquid state? No.

Why? Because the particles are already touching, so cannot be brought closer together.

Can we compress matter in the gas state? Yes.

Why? Because the particles have space between them, so they can be forced closer together.

Let's have a go at this question.

Particles in the liquid and solid states are touching so.

A, they can be forced even closer together.

B, they cannot be forced closer together.

C, they can be made to overlap.

D, they can be destroyed.

The correct answer is B.

Particles in the liquid and solid states are touching so they cannot be forced closer together, and therefore, we cannot compress substances in the liquid and solid states.

Well done if you got that question correct.

Time for our final practise task of today's lesson and this task is split into two parts.

First of all, can you identify which states of matter have each of the properties below? There may be more than one state of matter with each property.

Pause the video now, read through those different property statements that are present in the table and decide whether they refer to matter in the solid, liquid, or gas state.

I'll see you in a moment when you're ready to go over the answers.

Let's see how you got on.

The property, it will take the shape of the whole container refers to matter in the gas state.

It will take the shape of the bottom of the container is matter in the liquid state.

It will not take the shape of the container refers to the solid state.

It can flow and be poured refers to matter in the liquid and gas state.

It cannot flow or be poured refers to matter in the solid state.

It can be compressed refers to matter in the gas state.

And finally, it cannot be compressed refers to matter in the solid and liquid state.

Hopefully, you got most of those correct and you were able to identify which states of matter have those properties.

For question two, you need to answer the following questions using the words particle or particles, forces of attraction, and energy in your answer.

Draw diagrams to help with your explanations.

And the two questions are A, explain why substances in the solid state cannot be compressed, so take up less space, but substances in the gas state can.

And for part B, explain why if you take the lid off a container containing a substance in the gas state, it will fill the room, but substances in the solid state will not.

Pause the video now, try and add as much detail as possible to your answers and remember to use those keywords.

Question 2A.

When a substance is in the solid state, its particles have no space between them so they cannot be made to move closer together as they are already touching.

This means that solids cannot be compressed.

You should have included a diagram which will show the particles present in the solid state.

The particles will be arranged in a regular arrangement and the particles should all be touching.

When a substance is in the gas state, its particles have space between them so they can be made to move closer together as they are not already touching.

This means that gases can be compressed.

You should have a diagram showing the particle model for the gas state.

Well done if you drew both of your diagrams correctly and you included lots of those key details in your answer.

2B.

When a substance is in the gas state, its particles have enough energy to overcome the forces of attraction holding them together, so the particles are free to move quickly in all directions.

This means that the particles in the gas state can escape when the lid is removed and so they are free to fill the shape of the room.

When a substance is in the solid state, its particles do not have enough energy to overcome the forces of attraction holding them together.

Therefore, they cannot escape from the container when the lid is removed.

We have images there showing the particles in the gas state and in the solid state, and you can see the particles in the gas state are all spread out and they are moving quickly in all directions.

The particles in the solid state are in fixed positions held together by forces of attraction.

We have reached the end of today's lesson on the particle model.

Before we go, let's summarise some of the key points we have covered in today's lesson.

There are three states of matter: solid, liquid, and gas.

A substance in the gas state can be compressed because there is empty space between the particles.

A substance in the liquid or solid state cannot be compressed because the particles are already touching.

A substance in the gas state will take the shape of the whole of a container, and a substance in the liquid state will take the shape of the bottom of a container as the particles can move past each other.

A substance in the solid state cannot flow because the particles vibrate in a fixed position.

Well done for all of your hard work throughout today's lesson.

I hope you've enjoyed the lesson and I hope you're able to join me for another lesson soon.