Hello, scientists.

My name is Mr. Wilshire, and in this lesson we're going to be looking at evaporation and condensation in the water cycle.

The outcome of this lesson is I can identify the part played by evaporation and condensation in the water cycle.

There are some keywords for us to remember as we work our way through this lesson.

The first is evaporation, next water vapour, then it's water cycle, after that condensation, and finally precipitation.

Don't worry if you're not too sure what some of these words mean.

The definitions are on the screen for you now, so if you need to, you can pause the video here and have a quick recap.

The first part of this lesson is called water travels from the land to the atmosphere.

Jun and Sofia have been learning about evaporation.

Take a moment here to have a think.

Can you explain to a partner what evaporation means? Pause the video and have a go.

Restart when you've done that.

How did it get on? What does evaporation mean? Well, evaporation is the change of state from a liquid to a gas.

There you can see a cup with some water in it being changed into a gas.

So Jun says, "When water evaporates, what happens to all the water vapour in the air? I wonder, does it go to space?" Sofia says, "Well, wouldn't we eventually just run out of water if all the water vapour is lost into space?" Do you know what happens to water vapour in the air? Does it go to space? Have a think.

Restart the video when you've done that.

So does all the water vapour go to space or does something else happen? Let's find out more.

Well, water doesn't leave Earth's atmosphere.

Here you can see Earth and an image of its atmosphere.

So you can see there that the atmosphere around the Earth is made of different layers made of different pressures and different temperatures as well, so it's actually quite a long time until we get out into space.

The atmosphere is the layer of gases that surrounds the Earth.

That's what it's known for.

Water moves around between Earth's surface and its atmosphere in what is called the water cycle.

The water cycle is the name of the journey that water takes as it moves from the oceans, the rivers, the lakes, or land to the atmosphere and back again.

Sofia says, "Where does the water cycle start, though?" Hmm, that's a good question.

I wonder if you know.

Can you discuss this and restart the video when you've done that? So where does the water cycle start? Does it start in space or does it start underneath our feet? Jun says, "The water cycle doesn't really have a beginning or an end.

It's just a cycle." We can begin to understand the cycle by first thinking of water on land.

So this is a good place to start, but it doesn't mean that this is the start of water or where the water comes from.

Here you can see an image of the land, sea, and sky.

And we've highlighted the land there because this is where we're going to start talking all about the water cycle.

So where can you find water on land? Have a think.

Do you find water in just cups, or does it come out the taps, or is it anywhere else? So where can you find water on land? Let's find out more.

Let's stop and think first.

What's the name given to the journey of water from Earth's surface to the atmosphere and back again? Is it the water circuit, the water recycling, or the water cycle? The correct answer here is the water cycle.

So on land, water can be found in ponds, lakes, streams, rivers, seas, and oceans among other places as well.

There's a lake there and there's also a river.

Lots of greenery around where water is, isn't there? Sofia says, "How does water get from the land or sea into the atmosphere, though?" I wonder, do you know? Have a quick discussion and restart when you've done that.

So how does water get from the land or sea into the atmosphere? Well, water from lakes, rivers, and seas on the Earth's surface evaporates to form water vapour in the atmosphere.

Here you can see an example of liquid water evaporating from Earth's surface.

So there's liquid water on the land, and that evaporates and moves up into the atmosphere in the form of water vapour.

Now the children are discussing this and the water cycle in general.

Jun says, "There is no water cycle on cold days because evaporation only happens in the sun." Sofia says, "The water cycle occurs all year and in all weathers." Andeep says, "There's no water cycle in winter because it's too cold." Well, who do you agree with here and why? Have a quick discussion and restart when you've done that.

How did you get on? Were you able to discuss, and who did you agree with and why? Well, Sofia is correct.

The water cycle occurs all year, and it occurs in all weathers as well.

It doesn't matter about the temperature, but the temperature might affect how quickly this might happen.

The water cycle occurs all year and in all weathers.

Even though evaporation happens more quickly at higher temperatures, it takes place in all weathers.

Let's stop and think.

By what process does water move from the land to the atmosphere? Is it by melting, freezing, evaporation, or condensation? The correct answer here is through the process of evaporation.

Here's Task A.

Are these statements always, sometimes, or never true? Have a read of each of those statements there and decide.

Put a tick into each box.

The first statement is water doesn't leave Earth's atmosphere.

What do you think? Is that always true, sometimes true, or never true? Next, the water cycle begins with water on Earth's surface.

Then, there is no water cycle in winter because it is too cold.

Next, evaporation is the change of state from a liquid to a gas.

And finally, water in gas state is called gas vapour.

You need to read each of those statements.

Have a think.

Is it always true, sometimes true, or never true? Best of luck with your task.

Restart when you've done that.

How did you get on? So what did you agree with here? The first one said, "Water doesn't leave Earth's atmosphere." That is always true.

The next one says, "The water cycle begins with water on Earth's surface." That's sometimes true.

That's where we like to think it starts.

But remember, it's a cycle.

It's continuously ongoing.

The next one down there says, "There is no water cycle in winter because it's too cold." That's never true.

Remember, evaporation can happen at any temperature.

"Evaporation is a change of state from a liquid to a gas." This is always true.

And, "Water in gas state is called gas vapour." That is never true.

Hopefully, you've been able to show off some of the things that you know, and don't forget, if you've got some of these wrong, that's okay because now you're going to know the answer, aren't you, and move forward knowing more.

The next part of this lesson is called water travels from the atmosphere to the land.

Sofia says, "If the water in the atmosphere doesn't rise into space, what does happen to it?" Well, do you know how the water returns to the Earth's surface? It's always rising up.

Do the astronauts send it back down to Earth? I don't think that's right.

Pause the video here and discuss.

Restart when you've done that.

So how does the water return to the Earth's surface? Well, water can return to the Earth as rain, snow, hail, or even sleet.

There you can see two different images of that exact thing happening.

Hail is small pellets of ice or frozen rain.

Sleet is rain which contains some snow.

So as it moves through the water cycle, water can be in the liquid state, gas state, which is water vapour, or solid state, which is ice.

Depending on which state it's going to be in, will give you the different type of thing that will fall to the ground.

Could be rain, could be sleet, could be hail, it could be snow.

Let's stop and think.

True or false? Water can only be in the liquid or gas state as it moves through the water cycle.

The correct answer there is false.

As it moves through the cycle, water can be in the liquid state, gas state, which is water vapour, or solid state, which is ice.

So as water vapour rises in the atmosphere, it begins to cool down.

Remember, it can get very cold out towards space.

So as things are rising up off of the ground, it can then start to rapidly cool down.

So Sofia says, "What happens when water vapour cools down?" Do you know? Have a quick discussion and restart the video When you've done that.

Jun says, "I know that as water vapour in my bathroom touches the cold tiles, it condenses back into liquid water." Have you ever noticed this if you are in the bathroom or maybe even in the kitchen if you've been cooking and it's got very hot? You can see there water droplets on a cold tile.

So the water vapour in the atmosphere begins to cool.

It then condenses to form masses of tiny water droplets, and water condenses here to form clouds.

So it's held in the atmosphere as a cloud, and the clouds can then be moved around by the wind.

So tiny water droplets as clouds move around as our water vapour cools and condenses.

Let's stop and think.

What happens to water vapour as it rises in the atmosphere? Does it warm and evaporate more, does it cool and condense, or does it travel into space? The correct answer here is it cools and condenses.

What happens to make clouds form? Does water vapour condense, does liquid water evaporate, or does liquid water freeze? The correct answer here is water vapour condenses.

Now the droplets of water in the clouds get larger.

They then get heavier and eventually they fall as rain, snow, hail or sleet.

There you can see an image of a cloud and rain falling from that cloud.

Jun says, "Why don't all the water droplets fall as rain?" Do you know? Have a quick discussion.

Restart when you've done that.

So did you get it right? When air in the atmosphere is very cold, the water droplets freeze and change into solid state water, which is snow or ice.

That can then give us very different types of weather, can't it? Rain, snow, and sleet are known as precipitation.

Here you can see an image of precipitation as hail.

Precipitation is water, in the solid or the liquid state, which falls from the atmosphere to Earth's surface.

Sofia said, "I heard the word precipitation on a weather report." You may have done that as well.

Remember, all of this water is evaporating.

It's rising up into the atmosphere, and when it's there, it can then begin to cool, which then helps it to fall back down to Earth as rain, hail, snow, or even sleet.

So once back on the Earth's surface, the water cycle begins again.

So evaporation from the rivers and from the seas rises into the atmosphere.

That water vapour then begins to cool and condensation happens.

That creates clouds.

This rains, precipitates, onto the land and the liquid water begins to evaporate all over again.

So I wonder which part does come first because it is just a cycle, isn't it? It goes on, and on, and on.

Remember as well, that rain, snow, hail, or sleet will fall onto the land and then form eventually into the rivers.

Those rivers will then flow into lakes, or ponds, or even into the sea.

Evaporation can happen in all of those areas.

Stop and think.

True or false? Precipitation is water, in the liquid state, which falls from the atmosphere to Earth's surface.

The answer here is false.

Precipitation is water, in the solid or liquid state, which falls from the atmosphere to the Earth's surface.

You need to remember that it's not just water in the liquid state that falls.

Rain isn't the only type of things that falls from clouds.

It could be hail, snow, or even sleet.

Here's Task B.

Make a model water cycle using a recycled clear bag.

You can add some arrows to represent the water cycle and labels in suitable places, including evaporation, condensation, and precipitation.

Then if you add a little bit of water into the bottom of the bag, you can then create your very own water cycle and make some observations after a few hours.

Have a little go at this task, and restart the video when you've done that.

So here is an example of what could have happened to yours that may be similar.

"The bag had gone misty or foggy, showing that some of the liquid water had evaporated and risen.

When we press lightly on the surface of the bag, some of the water vapour condensed and could be seen as droplets of liquid water." So this is showing exactly what happens in the water cycle.

There you've created your very own model.

Well done.

Let's summarise our lesson.

Water doesn't leave Earth's atmosphere.

It moves around in what is called the water cycle.

Water evaporates from sources such as seas and rivers, as well as from the Earth's surface.

As it moves through the water cycle, it can be in the liquid state, the gas state, which is vapour, or the solid state, which is ice.

Water vapour rises into the atmosphere then cools and condenses into clouds.

Well done for completing that lesson.

Hopefully you've got a better understanding of the water cycle and how it can create the rivers, how it can create clouds, rain, snow, sleet, and even hail.

I've be Mr. Wilshire.

Thank you very much for listening.