Welcome to today's lesson on boiling and condensing.

I'm Mrs. Mytum-Smithson.

I'm gonna help you learn today.

This is from the unit's, solid, liquid, gas states and changes of state.

By the end of today's lesson, you should be able to tell me how you can measure the boiling point of water and explain what happens to particles when a substance in the gas state condenses.

The keywords for today's lesson are boiling, boiling point, condensing, condensing point.

On the next slide, there's some sentences that use these keywords if you wish to read them, pause the slide, have a read, and then press play when you're ready to start the lesson.

This lesson consists of four learning cycles.

First, we're going to look at how to measure boiling point.

Then we're going to look at exactly what are in those bubbles when boiling happens.

We're then gonna have a look at condensing and condensing point.

And finally we're going to compare condensing and boiling.

So let's get going.

First of all, measuring boiling point, the temperature at which a substance changes from a liquid state to a gas state is called the boiling point.

Different substances have got different boiling points.

The boiling point of toffee is 150 degrees C.

The boiling point of water is 100 degrees C, when the water boils, it produces steam.

Steam is water when it is a gas, so steam is water in the gas state.

Let's have a quick check.

Choose a correct ending to the sentence.

The boiling point is a temperature when a substance changes from a solid state to a liquid state, liquid state to a solid state or liquid state to a gas state, select your answer.

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

Well done if you said liquid state to gas state, indeed the boiling point is that exact temperature.

When a substance changes from being in a liquid state to a gas state, Weldon, if you got that one right.

Another quick check.

True or false.

The boiling point of all substances are the same.

Is that true or is that false? Now, I want you to think of a justification for that answer.

So all substances change from a liquid state to a gas state at 100 degrees C.

Water changes from a liquid state to a gas state at 100 degrees C.

So I want you to write true or false, A or B.

Pause the video if you need some thinking time, press play when you're ready for the answer.

Well done if you said that that was false, the boiling point of all substances are actually different.

So that means that water changes from a liquid state to a gas state at 100 degrees C, but other substances will boil at different temperatures.

Well done if you got that one right.

Some more statements now.

So for these two statements, I want you to say, if you are sure that this is right, if you think it's right, if you think it's wrong or if you're sure it's wrong.

So steam is watering the gas state.

So is that right or is that wrong? And how right do you feel that you are? Or how wrong do you feel that you are? And B, steam is used to describe all hot gases.

So are you sure that that's right? Do you think it's right? Do you think it's wrong or are you sure it's wrong? Put your answers, pause the video if you need some thinking time, press play when you're ready for the answers.

So well done if you put that steam is water in the gas state, that's absolutely right.

And steam is not used to describe all hot gases, just water.

So that one is wrong.

Well done if you've got those two correct.

To measure the boiling point of water, we can use this equipment.

We've got heat resistant mat that's going to protect the bench.

On top of that, we're going to place a tripod, and that's going to create this space for the Bunsen burner to go in and the gauze to go on top.

So the Bunsen burner, we put that on a blue flame to heat the water.

The gauze is a metal mesh sometimes with plaster of Paris poured in a circle shape, and that's where you're going to put the beaker.

So then you've got the beaker with the water in it.

And then finally we've got a thermometer.

The thermometer is used to measure the temperature of the water.

Let's see how much you remember.

Which equipment is used to measure the temperature of the water.

Is it this piece of equipment, this piece of equipment, or this piece of equipment? Which one is used to measure the temperature of the water? Pause the video if you need some thinking time, press play when you're ready.

Well done if you said A, that is the thermometer that is used to measure the temperature of the water.

So which equipment is used to heat the water? Is it A, is it B, or is it C? Which equipment is used to heat the water? Well done if you said B.

That's the Bunsen burner that is used to heat the water on the blue flame.

To read a thermometer your eye should be levelled with the top of the cord alcohol in the thermometer.

This means you might need to bend down to have a little look.

So here's an example.

So the thermometer alcohol is at this level, and you can see this I which is side on, and you can see the dotted line represents the line of sight.

So that's where you should be looking.

This allows you to get an accurate temperature.

Here's another version.

So here you can see that the thermometer is much hotter, so you're going to need to place your eye level with the top of it.

You should not do this so, so if your eye is not level with it, so if it's too high or too low, then you might read an incorrect temperature because the alcohol in the thermometer won't line up with the scale on the glass.

Which is the correct angle to read the temperature on the thermometer? Is it A, is it B or is it C? Have a little look where the line of sight is and I want you to tell me which is the most accurate way.

So the correct angle to read the temperature on the thermometer.

So well done.

If you said C, that's absolutely right.

The line of sight here represented by the dotted line is at the top of the red alcohol in the thermometer.

If you checked B or A, you wouldn't get the correct temperature.

So how to measure the temperature of boiling water? First of all, you need to set up your equipment as we described previously.

Turn your Bunsen burner onto the blue flame.

Wait to see it boiling.

And you can see in the animation the little video there, you can see that there's bubbles being produced.

And then finally, read the temperature on the thermometer.

Here's task A: order the instructions on how to measure the temperature of boiling water.

So you've got A, B, C, and D.

These instructions are in the incorrect order.

That's task number one.

So the second part of the task is to sketch a diagram of how you should read the temperature on a thermometer.

You can just sketch a thermometer like this.

Then what I want you to do is draw an I and draw a dotted line to represent the line of sight.

Where should you be looking to measure that temperature accurately? Pause the video now and then press play when you're ready for the answers.

So here's the correct order of how to measure the temperature of boiling water.

First of all, it's C, set up your equipment, then it's B, turn on your Bunsen to the blue flame.

Remember, D is wait to see it boil and you'll know it's boiling when it's bubbling.

And then you want to read the temperature on the thermometer.

So that is A at the end.

So your answer should be C, B, D, and A.

And you should have drawn a diagram that looks something like this.

So the line of sight.

So that dotted line should be at the top of the red part of the thermometer.

Well done if you've got those two tasks correct.

We've now looked at measuring the boiling point.

The next part of this lesson is to look at what happens with the bubbles that are formed when boiling.

Then we're gonna move on to condensing and condensing point, and then we're gonna compare condensing and boiling.

When a substance changes from the liquid state to the gas state, you can see if you watch the animation, what happens to the particles.

It's going to take a much larger volume because it's going to expand many times the volume that it takes up when it's a liquid.

There's only space between the particles, nothing else, and the particles themselves stay the same size.

So if you watch the animation, you can see that they start to move around rapidly with spaces in between them.

So when boiling a liquid, we're going to have a look at our favourite substance water.

And you can see on the picture, here's a picture of some boiling water.

The particles have changed into the gas state and become bubbles, and then those bubbles rise to the top and then they're released into the surrounding air.

Here you can see the pan with an egg in.

It has got some water that's bubbling.

The bubbles have risen to the surface and then they will burst and release the boiled water in the gas state into the air.

So the bubbles formed when boiling.

So water in the liquid state when heated at to 100 degrees, that will form bubbles and those bubbles will be bubbles of steam.

So that's bubbles of water in the gas state called steam.

Ethanol, which are type, which is a type of alcohol, in the liquid state, it's going to have a different boiling temperature.

Different substances have got different boiling temperatures.

So this one, when it boils, it's going to heat up and boil at 78 degrees.

And the bubbles this time will not contain water.

They will just form bubbles of ethanol in the gas state.

The water inside this kettle is boiling.

You can see bubbles.

What's inside the bubbles? Is there nothing inside of them? Only air particles, only water or steam particles, water steam particles and air particles.

What's inside those bubbles? Pause the video if you need some thinking time, then press play when you're ready for the answer.

Well done if you said only water or steam particles.

The bubbles are always made up of the substance that is boiling.

A quick check for understanding: what temperature does water boil at? Is it 98, 37 degrees C, 100 degrees C or 78 degrees C? I want you to tell me if you are sure that it's right, you think that it's right.

You think that it's wrong, are you sure that it's wrong? Well done if you said that water boils at 100 degrees C, obviously all of the other three answers, 98, 37 is human body temperature, and 78 are all incorrect.

Well done if you've got that one right.

So true or false? The boiling point of substance A is 56 degrees C.

Bubbles of air are produced.

So I want you to tell me if that statement is true or is it false.

Then I want you to tell me about substance A.

So when substance A boils, bubbles containing only substance A in the gas state will be be produced, or when substance A boils, bubbles containing air will be produced because all bubbles are made of air.

Pause the video if you want some extra thinking time, then press play, when you're ready for the answers.

That statement is false.

The reason for this is when substance A boils, bubbles only containing the substance A and the gas state will be produced.

So well done if you got that one right.

Here's task B for you.

So this one, if you have a look at the picture, we've got some sweet corn.

It's being cooked in the boiling water and bubbles can be seen.

Jun, Izzy and Sofia are explaining what they see.

I would like you to complete their answers to make them correct.

So Jun is saying, "when water in the liquid state is 100 degrees C, it changes to the something state." Izzy saying, "there is only something between the particles of water or steam in the bubbles." And Sofia is saying, "the bubbles only contain something particles." Pause the video now, then press play when you're ready for the answers.

Welcome back.

Here's the answers.

When water is in the liquid state is 100 degrees C, it changes to the gas state.

Well done if you've got that one.

Then Izzy, there is only space, remember, between those particles of water in the bubbles.

So there's only space.

And the bubbles only contain water particles.

So there's no air in there.

There's just water particles in there.

Well done if you've got all three of those correct.

We've had a look at our first two learning cycles.

So we've had a look at how to measure the boiling point.

We've then talked about what's gonna be in the bubbles, and now we're gonna have a look at condensing and the condensing point.

You can often see condensation on windows and mirrors.

Here's what it looks like.

Here's some condensed steam on a window.

This is where the steam, so that's water in the gas state, has cooled and formed liquid water.

The condensing point and boiling point at the same temperature for a substance.

If we have a look at this, you're familiar with boiling water.

Its condensing point is 100 degrees C, its boiling point is also 100 degrees C.

Now we'll have a look at something that's a slightly more unusual example.

Liquid nitrogen has got a condensing point of minus 196 degrees C.

It's also got a boiling point of minus 196 degrees C.

And mercury that's got a condensing point of 357 degrees C and a boiling point of 357 degrees C.

Let's have a check for understanding now.

The condensing point and the boiling point are: the same temperature for all substances, the same temperature for a specific substance or different temperatures for a specific substance.

Pause the video if you want some thinking time.

Press play when you're ready.

Well done if you said they are the same temperature for a specific substance.

If we have a look at this arrow, you can see that I've put increasing temperature.

So on the left hand side, the arrow's blue on the right hand side it's red.

So this represents colder and warmer temperatures.

You can see I've put some labels on it saying condensing point and boiling point.

So substance is in a liquid state below its condensing point and in a gas state above its boiling point.

So we put those on our arrow.

We can see liquid state below the condensing and boiling point, gas state above the condensing and boiling point.

Let's have a quick check.

Condensing only happens with water.

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

So only water changes from a gas state to a liquid state.

All substances in a gas state can condense and become a liquid state.

So what do you think? Pause the video now if you'd like some thinking time.

Press play when you're ready.

Well done if you said false, it is false.

Condensing happens with other things, other substances other than water.

So all substances in the gas state can condense and become a liquid state.

There's four students that are a little bit confused about condensing and condensing points.

I would like you to correct each student's one error.

So each student is gonna give a statement, something's wrong about it, I want you to correct it.

So Aisha says, "A substance is in a liquid state above its boiling point." Sofia says, "A substance is in a liquid state above its condensing point." Lucas says, "The condensing point and boiling point are different temperatures for a substance." And Jacob says, "Condensing is liquid state going to solid state." Pause a video now to correct each student's error, then press play when you've got the answers.

Well done for completing task C.

Here's the answer.

So Aisha says, "A substance is in a gas state above its boiling point." Sofia says, "A substance is in a liquid state below its condensing point." The condensing point and boiling point are the same temperature for a substance, but you've managed to help Lucas.

And Jacob says, "Condensing is going from a gas state to a liquid state." So well done for correcting the errors.

So well done for working so hard in this lesson so far.

Let's have a look what we've got to do.

So we've done measuring boiling point.

We've talked about bubbles when boiling.

We've looked at condensing and condensing point.

Now what we're going to do is we're gonna compare condensing and boiling.

When a substance condenses, the substance changes from a gas state to a liquid state, it's the reverse of boiling.

So here if we have a look at the particle diagrams, you can see on the left hand side we've got three particles.

They're in a gas state.

You can see that there's some spaces between them and a liquid state.

They're touching, they're in a random arrangement.

And we've got two arrows, one which say gas to liquid, which is condensing, and the other one saying liquid to gas, which is boiling.

So when a substance condenses, the particles move closer together.

And when the substance boils, they move further apart.

True or false? When a substance condenses, the particles move close together.

Is that true or is that false? Particles are far apart in a gas, but touching a liquid.

When a substance boils, the particles move close together.

Choose true or false, and A or B.

Well done if you said that that statement was true.

And the justification for that are that particles are far apart with just space between them in a gas but touching in a liquid.

Well done ff you've got those right.

You are working really hard.

Now we're going to have a look at comparing boiling condensing.

I've got a table here and some animations that show boiling and condensing.

So before for boiling particles move in a random arrangement sliding past each other and afterwards they move very quickly in random directions.

For condensing, you can see it's the opposite.

So particles move very quickly in a random direction.

And then after condensing, as you can see it's happening now they then move in a random arrangement sliding past each other.

So if you have a look at those animations, you can see that the condensing is the particles are coming very quickly to random sliding past each other.

And it's the opposite for boiling.

So let's have a look at volume.

When a substance in the liquid state boils, it takes up much more volume than the substance when it's in the liquid state.

You can see here the particles are spread out in the gas state and that there are spaces between them.

And then when it condenses, those particles move closer together and take up less space.

Let's have a quick check for understanding.

Find the two correct statements.

Condensing increases the space between particles.

Boiling increases the space between particles.

Condensing increases the volume of a substance, or boiling increases the volume of a substance.

I want you to select the two correct statements.

Pause the video now for thinking time and press play when you've got the answers.

Well done if you said B, boiling increases the spaces between particles as they become a gas and boiling increases the volume of a substance.

Well done if you've got those two correct.

Now the final task of the lesson.

Help Izzy sort the statements to compare condensing and boiling.

So you're going to need a table like Izzy's got with condensing and boiling as a header and three spaces to write these statements.

So particles move further apart, particles move closer together.

You want to put those statements either in condensing or boiling.

Particles gain space between them, particles lose space between them.

Substance decreases in volume or substance increases in volume.

All of those six statements need to be sorted into that table.

So pause the video now while you do that task, then press play when you're ready for the answers.

I hope you got on with that task okay.

We've got condensing and boiling.

So in condensing particles move closer together, which means that in boiling, they move further apart.

In condensing, particles loose space between them.

And in boiling, they gain space between them.

For condensing, the substance decreases in volume.

For boiling, that means that it increases in volume.

Well done if you got that correct.

Here's a summary for today's lesson.

The condensing point and boiling point are the same temperature for a substance.

For water, this is 100 degrees C.

Steam is the name of water in the gas state.

A substance increases in volume when boiled.

So it goes from liquid to gas state.

A substance decreases in volume when condensed from gas to liquid state.

Particles move further apart when boiled and move closer together when condensed.

Here's a diagram that sums up what happens to the particles.

You've worked really hard this lesson.

Well done for completing the tasks.

I hope to see you sometime soon.