Lesson video

Hi, I am Miss Mia, and I'm really looking forward to teaching you this lesson today.

In this lesson, you'll be able to describe the difference between the temperature and the energy of an object or substance.

Your key words are on the screen now and you can write them down if you'd like to.

So, you've got random, temperature, thermal energy store.

Super, let's find out what these key words mean.

Random, something that happens or is chosen without any specific pattern, reason, or plan, like whether a flip will land heads up or tails up.

Temperature, a measure of how hot or cold something is.

Thermal energy store, the energy a substance stores because of the random motion of its particles.

Great, let's move on.

So, this lesson is all about energy and temperature.

We have three lesson cycles today, and our first lesson cycle is to do with particles and temperature.

We're then going to move on to energy of hotter objects.

And then lastly, we'll be looking at energy of larger objects.

Let's begin.

Now, you may remember that the spacing between the particles of a substance depends on whether it's in a solid, liquid or gas state.

A solid has very small spaces between its particles.

A gas has large spaces between its particles.

And lastly, a liquid has small spaces between its particles.

The arrangement of particles in a substance can be regular or random.

A solid has a regular arrangement, a gas has a random arrangement, and lastly, a liquid has a random arrangement.

Over to you.

Which of the diagrams below show the arrangement of particles in a liquid?

Is it a, b, or c?

What do you think?

You can pause the video here and click play once you've got the answer.

So, what did you get?

If you got c, you are correct.

C shows the arrangement of particles in a liquid.

They're not too far apart, but they're not in a regular arrangement either.

Let's move on.

The direction in which the particles move in each state of matter is random.

So, here in a solid, the particles vibrate in random directions.

In a gas or liquid, the particles move past each other in random directions.

Over to you.

Different substances can be in a solid, liquid or gas state at room temperature.

In which state a, do the particles have a random arrangement?

And b, do the particles move in random directions?

You can pause the video here and click play once you've got the answer.

So, how did you do?

Well, liquids and gases, the particles have a random arrangement.

And for solids, liquids and gases, the particles move in random directions.

The higher the temperature, the faster the random motion of the particles.

So, here we can see solid water -20 degrees Celsius.

The liquid water is at 20 degrees Celsius, which shows that the higher the temperature, the faster the random motion of the particles.

The faster the particles move, the further apart they push each other.

So, let's have a look at this diagram.

So, the bottle cap is at 20 degrees Celsius.

There are smaller spaces between the particles, and then when it comes to the liquid within the bottle, if it's at 20 degrees Celsius, we see that the particles still have a random arrangement, but they're not moving as fast.

Then as we increase the temperature, we can see that the bottle cap expands at 60 degrees Celsius and the water level rises and we can see that there are larger spaces between the particles.

Let's move on.

Over to you.

An aluminum bottle cap expands if you put it in hot water.

What happens when it expands?

Is it a, its particles vibrate faster.

b, The spaces between its particles get smaller.

c, Its particles get bigger, or d, The bottle cap gets wider.

You can pause the video here and click play when you've got the answers.

So, what did you get?

a is true.

As an aluminum bottle cap expands by putting in hot water, its particles begin to vibrate faster.

The bottle cap gets wider.

Well done if you managed to get that correct.

Let's move on.

The increase in space between particles can most easily be seen with a gas.

So, here we have an example.

The balloon acts as a flexible bottle cap and there's trapped air in the bottle.

The hot water warms the air inside the bottle.

The balloon inflates because the air expands.

The volume of a gas increases because its particles move faster.

They collide with each other, and the walls of the container, harder and more often.

This causes them to spread out.

So, here we have an example of slower particles moving around, and then we can see here at higher temperatures, the air particles push harder on the walls of the balloon causing it to expand.

Back to you.

What happens to particles of a gas if you increase its temperature?

Is it a, they get lighter?

b, They move faster.

c, They get smaller.

Or d, they collide with more force.

What do you think?

You can pause the video here and click play once you've got the answers.

So, what did you get?

If you got b, they move faster, and d, they collide with more force.

You are correct.

Well done, let's move on.

Task A.

I'd like you to draw the particle arrangements for a, a solid b, a liquid, and c, a gas.

Two, how does the movement of the particles and spacing between them change if you increase the temperature of a solid, and b, a liquid or a gas?

You can pause the video here and click play once you've completed this task.

So, how did you do?

Well, you may have drawn something like this for one.

So, with this solid you can see that the particles are close together and then for a liquid there's a random arrangement and then not as close together.

And for a gas we can see that the particles are very far apart because they have lots of energy.

Two a, in a solid, the particles vibrate faster and further and so the space between the particles increase if you increase the temperature.

And b, in a liquid or a gas, the space between the particles increase if you increase the temperature because the particles move faster and collide more often.

Well done if you managed to include some of those key points.

Let's move on.

Lesson cycle two, energy of hotter objects.

If an object has energy, it can do a useful job.

Hot water can keep us warm.

It has more energy than the same amount of cold water.

So, 40 degrees Celsius water has less energy than water at 60 degrees Celsius, which has more energy.

Heating a substance transfers energy to it.

So, here we've got an example of a kettle.

Inside the kettle we have water, we have casing, which is made of plastic.

And then an electric heater which is made of metal.

Once switched on, the electric heater gets very hot.

Here we can see very fast vibrating particles in metal.

Collision speeds up water particles.

The longer we heat a substance, the more energy we give it.

So, here we're heating water at 40 degrees Celsius for one minute.

And here we heating water at 60 degrees Celsius for two minutes.

And lastly, we're heating water here at 80 degrees Celsius for three minutes.

So, we can see here that the kettle that we're heating for a minute at 40 degrees Celsius will have less energy than the kettle that we're heating at 80 degrees Celsius for three minutes.

When we stop heating a substance, we stop transferring energy to it.

A kettle switches off automatically when the water temperature reaches 100 degrees Celsius.

And then once this happens, we can see here as shown in the graph that the water begins to cool slowly.

The higher the temperature, the more energy a substance has in the thermal store.

So, the amount of energy in the thermal store, we can see that at 20 degrees Celsius, less energy.

And then when it comes to 100 degrees Celsius, we definitely have more energy.

Over to you.

Compared to water at room temperature, which energy store does hot water have more energy in?

Is it a, elastic store?

b, magnetic store?

c, kinetic store?

d, thermal store?

e, chemical store?

Or f, gravitational store?

You can pause the video here and click play when you've got the answer.

So, what did you get?

If you got d, thermal store, you are correct.

Let's move on.

When a hot object cools the energy in its thermal store decreases.

So, here we've got a hot water bottle at 60 degrees Celsius.

It's got more energy.

And then as time goes by, the energy within the thermal store we can see here is decreasing.

And now it has less energy at 20 degrees Celsius.

How quickly the energy decreases depends on what the object is surrounded by.

And here we can see that the hot water bottle has got a cover made of wool.

A hot water bottle stays warmer for longer if it is wrapped in an insulator.

And that's also why you may notice that in stores and shops we now see a lot of hot water bottles that are sold with covers on them.

The energy that a hot object has isn't lost as it cools.

It is transferred to whatever it is in contact with and then to the surroundings.

So, here we can see in this image that the little boy or the object in contact with the hot water bottle and the hot water bottle is there.

Over to you.

When a hot object calls down, what happens to the energy in its thermal store and that of the surroundings?

So, we have a, energy of hot object.

Does it go up, stay the same or go down?

Or b, energy of surroundings.

Does that go up, stay the same or go down?

You can pause the video here and click play once you've completed this check for understanding.

So, how did that go?

So, the energy of a hot object in its thermal store goes down and the energy of the surroundings goes up.

Over to you.

Task B, complete the following statements using only the words more or less.

Compared to the water at room temperature, hot water has energy in its thermal store.

Heating water gives it energy.

After hot water cools, it has energy.

The better the insulation around a hot object, the quickly its energy is transferred to the surroundings.

You can pause the video here and click play once you've completed this task.

So, what did you get?

Well, compared to water at room temperature, hot water has more energy in its thermal store.

Heating water gives it more energy.

After hot water cools, it has less energy.

The better the insulation around a hot object the less quickly its energy is transferred to the surroundings.

Well done if you managed to get all of those correct.

Let's move on.

Lesson cycle three.

Energy of larger objects.

Energy is not the same as temperature.

The more of a substance there is at one temperature, the more energy it has.

So, here we have two hot water bottles.

More hot water will keep you warmer for longer because it will have more energy.

The more there is of a solid, liquid or gas, the more energy we need to give it to change the temperature by the same amount.

Bringing two times as much water to the boil takes it twice as long with the same kettle.

Over to you.

If it takes a kettle four minutes to boil enough water for four cups of tea, how long would it take to boil enough water for one cup of tea?

Is it a, one minute.

b, two minutes.

c, three minutes.

Or d, four minutes?

You can pause the video here and click play once you've got the answer.

So, what did you get?

Well, you should have got one minute.

And that's because if it takes four minutes to boil enough water for four cups, it would take one minute to boil one cup of tea.

Because for every minute, one cup of tea will be boiled.

It takes more energy to warm up a distance to a particular temperature if there is more of it.

This is because it has more particles when there is more of it.

One cup of water has six quintillion particles.

Two cups of water has 12 quintillion particles.

Basically double the amount.

So over to you.

Which bowl contains porridge with the most energy in its thermal store?

Is it a, b, or c?

What do you think?

You can pause the video here and click play when you've got the answer.

So, what did you get?

If you got a, you are correct.

We can clearly see here that there is far more porridge in bowl a than bowl b and c, which means it will have more energy in its thermal store.

Well done if you got that correct.

Let's move on.

Objects at higher temperatures can have less energy than those at lower temperatures if they have fewer particles.

So, we've got a very hot flame here at 800 degrees Celsius and a bathful of warm water at 40 degrees Celsius.

Less energy, more energy.

The less energy an object has in its thermal store, the less energy it has to transfer to other objects to warm them.

The increase in temperature of a bathful of water when you put in a lit match is very, very small.

Which of the bowls has porridge with more energy in one spoonful then porridge at 30 degrees Celsius?

Is it a, b, or c?

What do you think?

You can pause the video here and click play when you've got the answer.

So what did you get?

If you got a, you are correct.

A is the bowl that has porridge with more energy in one spoonful than the porridge at 30 degrees Celsius.

And c as well because it's at 45 degrees Celsius.

Task C, I'd like you to complete the following statements using only the words energy or temperature.

A thermometer measures .

Particles in an object move faster if the is higher.

The of a flame is higher than that of a bath of warm water.

The of a bath of warm water is higher than that of a flame.

Adding water at 40 degrees Celsius to a cup of water at 40 degrees Celsius increases its .

You can pause the video here and click play once you've completed the task.

So, what did you get?

Well, a thermometer measures temperature.

Particles in an object move faster if the temperature is higher.

The temperature of a flame is higher than that of a bath of warm water.

The energy of a bath of warm water is higher than that of a flame.

And lastly, adding water at 40 degrees Celsius to a cup of water at 40 degrees Celsius increases its energy.

Well done if you managed to get that correct.

We've now reached the end of our lesson.

Let's summarize our learning.

So, this lesson was to do with energy and temperature.

You now understand that we need to give an object energy to raise its temperature.

The higher the temperature of an object, the faster its particles move in random directions and the bigger the space between them.

It takes more energy to warm up more of a substance to a particular temperature because it has more particles.

And lastly, the more energy an object has in its thermal store, the more energy it has to transfer to other objects to warm them.

Thank you so much for joining me in this lesson, bye.