Lesson video

In progress...


So, before we get started, you're going to need same things as normal.

Pencil and pen, a ruler, something to write on, and some colouring pencils, if you've got them.

I've also got my trusty steed Lenny here who is very excited for today's lesson.

Yeah? Oh, my goodness! They are going to enjoy that.

Okay, we are ready to get started.

Go and get the things that you need now.

We are going to do our star words, so repeat after me.

Star words, star words, star words! Wow, you guys are ready for learning.

Okay, the first word today is stoma.

Your turn.

And the action for stoma is a very small spiral, like this.

So, can you say stoma? Your turn.

Well done.

It's different to seed.

Seed was this.

We had it.

So, stoma is a little circle.

So, my turn, your turn, stoma.

Your turn.

Well done.

The next word is stomata.

Can you say stomata? Well done.

Now your action for stomata is two little spy holes that you can put your eyes through.

So, stomata, your turn.

Can you put them up to your eyes like little binoculars? Stomata.

Well done.

I'll explain what on Earth stomatas are in a moment.

Next word.

Expelled, your turn.

Can you do it with the action? Expelled.

Your turn.

Wowee, can you whisper it? Expelled.

Good job, team.

Okay, next one.

Now, I'm going to say the word and then I'm going to give you the action.

So, the word is transpiration.

Your turn.

Can you say it again? Transpiration, your turn.

That's a long word, isn't it? With a tion suffix on the end.

Now the action for this is transpiration, okay? I'm going to do the action again.

Transpiration, and you'll see why during the lesson.

So, let's do it with the action, ready? Get your hands ready by your head, and then we go.


Let's do it one more time together.

Can you say it in a silly voice? Oh, transpiration! Lovely.

Well done.

You'll see all of these during the lesson.

The next one is absorbed.

Your turn.

Absorbed, your turn.

Well done.

And the last one is wilt.

The last one is.

Can you really get really droopy there? Put your arms out as if you're a really nice flower or nice plant, and then wilt.

Your turn.

Well done.

Okay, remember, if you see a star word you can put your hands on your head during the lesson.


So, the first we're going to look at is the transpiration stream.

We're going to do some reading together, and then we're going to write about it in our books.

So, transpiration stream.

Can you say that to your screen? Well done.

Okay, let's get reading.

One, two, three.

There are small holes on the underside of leaves called stoma.

I heard a star word! Stoma, your turn.

Good job.

These stomata, I heard another star word.

Stomata allow water to be expelled.

There's another one! Expelled, with the action expelled.

Now, expelled means leave.

Expelled means? So, if you expel something, then you force it to leave.

So, let's keep reading, expelled from the plant.

This will happen more quickly if it is a warm day or if there is a breeze.

Okay, so team, when you have a leaf, you have small holes on the underside of a leaf, and these holes are called stomata.

Or if you just focus on one of them, it's called a stoma.

So, water is expelled, is forced to leave, by these stomata, and then the water is expelled and it goes out into the air, okay? So, water is expelled through stomata.

Can you say that? Water is expelled through stomata.

Your turn.

Well done.

And you can see the arrows on the image are going away from the plant because the water is leaving.

Okay, let's keep reading.

You're doing really well so far at spotting your star words.

Well done, everybody.

As water is expelled, more water is soaked up through the stem of the plant, which causes water to be pulled up from the roots.

This causes water to be absorbed.

Oh, there's a star word.

Absorbed, your turn.

From the soil around the roots.

This process is called transpiration.

Can you pause the video and read that paragraph to yourself again now? Well done.

I hope you did the actions for all of those star words.

So, what happens here, team, is that in the soil, because the water is moving through the stem, then there needs to be water sucked up from the roots, and the roots get it from around it in the soil.

So, as it's soaked up from the stem, that causes the water through the roots to be absorbed.

Let's keep reading.

If there is not enough water in the soil, there will be less water in the stem and the leaves, causing the plant to wilt.

Well done.

So, if there's not enough water in the leaves, then it will wilt, and we also know that plants need water to survive.

So, there is very, very high chance that the plant will die.

Okay, so what I'd like you to do is pause the video and in your notebook or on your piece of paper, write the title transpiration stream.

Can you pause the video and do that now? Okay, so now you've got that written in your books.

What we're going to do is I'm going to show you what my book looks like.

Now, I actually went and picked a leaf from my garden, from a tree that I've got, and this is from a horse chestnut tree 'cause I really liked the shape of the leaves on this one.

You can either do the same, if you are able to, and your grownup says that it's okay to get a leaf, or you can draw yourself a plant in your book.

So, what I'd like to do is pause the video and draw yourself a plant in your book, and I'd like you to add on the arrows that show the absorption from the roots, the soaking up the water through the stem, and the expelling of water through the leaves.

Please add on your blue arrows now.

Off you go.

Okay, so what we're going to look at now is we're going to look at each stage in a bit more detail.

In box number one is written the stage that the blue arrows represent.

When water is expelled from the leaves it travels through the stomata.

It travels through the stomata.

Okay, so what do you think I've written under box number one? And I want you to tell your screen using the word stomata and using the word expelled.

Off you go.


Well done.

Let's see if you were right.

Expelled through stomata in leaf.

So, the water is expelled through the stomata in the leaf.

I want you to add that label on to your blue arrows by your leaves now.

Well done, everyone.

Okay, so the next arrow that we had was going up the stem, and water travels up the stem as the water is being expelled from the leaves.

What do you think I've written under box number two? Can you tell your screen using the words soaked up, and also the word stem? Tell your screen now.


Good try.

Shall we see if you're right? Soaked up through stem.

So, the water is soaked up through the stem as the water is being expelled from the leaves.

Can you add that label to your blue arrow next to the stem now? Well done.

So, those blue arrows, don't forget, are representing the movement of what? Can you tell your screen? They're representing the movement of water.

The movement of? Well done.

So lastly, as water is expelled from the leaves, it means it's being soaked up through the stem, which causes the water in the soil to be, what was that word? What was our star word? Absorbed through the roots.

Well done.

So, you can see the blue arrows of the water going into the roots.

What do you think I've written under box number three? Can you tell your screen now? Mm-hmm.

Yeah, good try.

Shall we see if you're right? I didn't give you any words for that one, but you had a big clue.

Absorption in roots.

So, the water is absorbed in the roots, and then it travels up the stem and out through the leaves.

Please, can you add that label to your roots now? Well done.

So, now we know that there are three main stages of transpiration stream in a plant.

We have this one, which is absorption.

Well done.

In the roots.

And we have this one, as it's being soaked up through the stem, well done, and then the water is expelled through leaves.

So absorbed, soaked up, and expelled.

Can you say those three stages with me? One, two, go.

Absorbed, soaked up, and expelled.

Your turn without me this time.

Well done, everybody.

Give yourself a part on the back.

I've been really impressed with how hard you've been working, and I can't wait to see some people's drawings and their label diagram on Twitter.

If you want to ask your grownup to share it, then you may do so.

So now, this is what your book should look like.

You've got your plant with your three main stages and your labels.

Okay, we've looked at the transpiration stream, so let's look at the transpiration rate.

Now, the transpiration rate is the speed at which water is transpired, which means how fast does it get soaked up? There are four conditions that affect the transpiration rate of a plant.

I wonder if you can think about what they might be.

Can you tell your screen if you think you know any of these already? Good try.

Okay, so the first condition that affects the rate of transpiration, remember rate is the speed.

Rate is the speed.

Well done.

Is sunlight, okay? So, if there is lots and lots of sunlight, then it will make it easier for the water to be transpired at a faster rate because the reason that is, is because water is being expelled very, very quickly.

So, the first condition is sunlight.

The first condition is? Well done.

The next one is, can you see that image? Now, those are little water droplets because the second condition is the humidity.

Now, humidity, can you say the word humidity? Can you say it again? Well done.

Now, humidity is something that is all around us.

In the air, there is lots and lots of water droplets and particles.

And depending on how many water droplets are in the air depends on how humid it is.

So, you know, sometimes if you've ever been to a hot country, you might find it really hot and dry, or you might find it really humid.

You get really sweaty really easily, and you can feel almost like there's water in the air.

If it is very humid and there's water already in the air, then transpiration will not be very fast.

However it is, if it is dry and there's very low humidity, then water will easily be expelled from the leaves.

So the second condition is humidity.

The second condition is humidity.

Well done.

The third condition is.

Is the wind.

Do you remember reading in our comprehension that if there's a light breeze, it will increase? Which means speed up the rate of transpiration.

So, if there is a wind or a breeze, it will be faster, okay? And lastly, the temperature.

If it is very hot, then transpiration will happen faster than if it is cold.

Can you now tell your screen, what are the four conditions that affect the rate of transpiration? Start from the top left, and work your way to the right.

Tell your screen now.

Sunlight, well done.

Humidity, well done.

Next one? Wind, well done.

And, woo, temperature.

Good job, everybody.

You've memorised them really well.

Okay, so now what I'm going to ask you to do is write out the five sentences on the screen into your notebooks.

Now, there are some words in the box at the bottom of the page, and you need to use those words to complete the sentences correctly.

We're going to do them together, so if they're a little bit small, don't worry.

Just have a listen and I'll make sure that you can hear the sentences and you can fill in the blanks.

So, sentence number one says, let's read it together.

Tell your screen.

The hmm rate is affected by hmm conditions.


Now let's look at the box at the bottom.

Let's read the words together.

Three, four, increase, wilt, stomata, transpiration, decrease, plant and flower.


Can you tell your screen those words again? Pause the video and read them out loud.

Well done.

So, sentence one, the hmm rate is affected by how many conditions? Well done.

The transpiration rate is affected by four conditions.

We just looked at those together.

Okay, sentence number two.

Let's read it together.

If it is a warm day, then the rate of transpiration will hmm.

Please pause the video and write out that sentence using a word from the box to fill in the blank.

Off you go.

Well done.

The word you should have chosen is increase because we said that if it's a hot day or the temperature is warm, then it will increase.

Sentence number three.

There are hmm, oh, I can't hear some of you.

There are hmm stages of transpiration in a hmm.

How many stages of transpiration in a? Pause the video and write down your sentence now.

Well done.

There are three stages of transpiration in a plant.

Well done, everybody.

I'm going to give you an awesome cheer because you're doing really well.

Two more sentences to go, and then it's time to look at our experiment.

Sentence number four let's read together.

One, two, three.

Water leaves the leaves through.

Hmm, water leaves the leaves through.

So, water's expelled through the leaves via, what were they called again? Stomata, well done.

So, water leaves the leaves through stomata.

And sentence number five.

If there is not enough water in the stem and leaves the plants will hmm.

I'm going to give you a clue for this one.

Pause the video and fill in sentence number five now.

Well done.

I'm sure you all got that one from my excellent clue, which was wilt.

If there's not enough water in the stem and leaves, the plant will wilt.

Okay, team, I am going to give you a rainbow cheer.

One, two, three.

Ah, because you've been working so hard.

It's now time for my favourite part of the lesson where we get to look at our experiment.

Let's go and take a look.

Okay, so welcome to the experiment.

Now that we've learned all about transpiration, we're going to carry out an experiment in which to prove it.

You need to ask a grownup if you would like to do this at home, or you can just watch my version.

You will need the following.

I've got three small jars full of water.

I've got some food colouring.

I've got a red and a blue, but you could just use one, or you could more than one, and I've got some celery.

So, if you want to, you can continue with this experiment.

If you want to pause the video, go and get your things.

So, what I'm going to do, I'm going to open my celery.

And celery is from a plant that you can see have some leaves.

So, what I'm going to do is I'm going to break off one.

And let's have.

I'm going to choose one with the leaves 'cause it'll work better.

So, let's take that one off, actually.

I can eat those later.

Let's waste not want not.

And two.

And three.

Okay, so I've got three plants of celery here.

Have to move them back a bit.

In my jars of water.

Now, one of the jars, I'm going to keep with clear water, and then I'm going to put some food colouring in the other ones.

And if, as we've said, the stomata in the leaves expire water, and they release it into the atmosphere, then the idea is that we're imagining that these celery plants are now in the soil.

And so, they're going to soak up the water from these jars, and using food colouring is so that we can see the water travelling up the celery.

So I'm going to put three drops of blue into the blue jar, and there we go, you can see it.

Going to give it a little stir so that the water is all blue.

And then I'm going to do the same with the red food dye in the other one.

It's just so you can have a comparison.

You don't need to do it with two different colours.

I just have both of them.

Now, you must make sure that you're really careful and that you don't drink the water and you don't spill the water, okay? The water is for the celery.

So now, what I'm going to do now is I'm going to leave it, and if we are correct that transpiration causes water to be sucked up the root of a plant, then we should notice that some of the water is soaked up in into the celery, and we should be able to see it in our celery plant.

Let's find out if it's going to work, okay? Wow, what's an amazing experiment that was.

So, it's now the end of our lesson together.

There is a learning review quiz after this video, so go and have a go at it now.

Well done today, everybody, and really, really good job on all of your science learning.

We'll see you next week.