Hello, scientists.

My name is Mr. Wilshire, and in this lesson we are going to be looking at the function of leaves.

The outcome for this lesson is I can describe why plants have leaves.

There are some keywords for us to think about as we progress through this lesson.

The first is leaf.

The next is function.

After that is carbon dioxide.

Then it's photosynthesis.

Finally, it's observation over time.

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

You can pause the video here and have a good think.

You can reset the video when you've done that.

The first part of this lesson is called parts of a plant.

A plant is a kind of living thing.

Which of these do you think are types of plant? Have a look at these pictures and decide.

Restart the video when you've done that.

So which of these is a type of plant? Hmm, let's have a look at these pictures.

There's one with lots of leaves, they're not all green though, are they? The next one is a type of grass, I think.

There's lots of thin leaves.

Oh, after that, there's lots of jagged spiky looking leaves.

There's a tree there, I know that's a plant.

And there's a flower there as well, purple, beautiful flower.

But is a flower a plant, or is it a type of plant, or is it a part of a plant? After that, there are some strawberries as well.

I love strawberries.

Well, all of these are living things.

All of these living things are types of plant.

There are over 300,000 different types of plants on Earth.

And plants come in lots of different shapes, sizes, and colours.

Just like the ones that you can see here.

All of those are plants, not just types of plants or parts of a plant, no, all of them are plants.

They're all living things.

Many plants have parts in common with each other.

Do you know the names of any of the parts of a plant? Have a look at this image here and decide what parts of plants do you know? Restart the video when you've done that.

So what are the names of these parts of plants? Roots often grow beneath the ground, meaning that they're usually very difficult to see, but sometimes, especially when the land shifts around it, you're able to see them, like you can with this tree here.

Or you can see when someone has dug up a plant.

You can see the roots there.

The roots are below the plant, usually beneath the soil.

Stems then grow from the roots above the ground.

There's two different types of stem there.

There's a long, smooth, and thin one, and there's also, oh, a very spiky and thorny-looking one as well.

Sometimes we use the word trunk to describe a thick woody stem.

The trunk here looks like it's from a tree.

It's got lots of bark on it as well, hasn't it? Have you heard of the stem of something being called a trunk before? Most plants also have leaves, which can grow in many different shapes and sizes.

Here you can see lots of different types of leaf.

There's a green one, an orange one, a red one, and there's also a very long one there with lots of other thin leaves coming off of it.

Some plants have also got flowers.

Have you ever seen a flower like this? This one looks like a buttercup, doesn't it? Sometimes you can shine it underneath your chin.

Flowers are often very brightly coloured, they're not just yellow.

They can also be seen on trees.

If they're on trees though, they're called blossom.

You can see an example of some blossom there.

It's very pink.

Let's stop and think.

Which of the following are parts of a plant? Is it skeletons, stems, leaves, roots, hearts, or flowers? The correct answer here is stems, leaves, roots, and flowers.

All of these are parts of a plant.

So this brings us on to the very first task.

Label the parts of the plants that you can see in each picture.

They're both different types of plants, aren't they? So I wonder if you can label the different parts that you can see.

Remember, sometimes the parts of them will grow under the ground, so we're seeing plants that have had something exposed.

There are more pictures on the next slide too, so pause the slide here and restart when you've done that, and then we'll move on to the next slide for some more plants for you to look at.

Pause the video here.

Continue when you're ready.

Here's the next slide.

So have a little look at these plants here and label the parts that you can spot.

Restart the video when you've done that.

How did you get on? Well, here are some examples of answers.

Hopefully we've spotted everything that you did too.

The flowers are at the top of number one there, and then you've got the stem underneath, the leaves joined onto the stem, and the roots at the very bottom.

In the second one, there are leaves at the very top at the end of the branches, and you can see the stem, or also known as the trunk, and also the roots which have been exposed.

They've come out above the soil.

Obviously that soil has been washed away over time.

In picture three, you can see the flower at the very top.

You can see the stem coming down the bottom, the leaves coming off the stems as well, and the roots below.

Oh, and I can also see on number three there, there are also some bulbs there.

Those are the type of seed that the plant has grown from.

And in number four there, there were flowers, but it's also called blossom on trees.

There's a leaf from the tree, and I can see one part there of the stem, or also known as a trunk, on the tree.

Well done for completing that task.

The next part of this lesson is called the function of leaves.

The function of something is the task or the job that it has.

So what is the function of leaves? Pause the video here and discuss.

Restart when you've done that.

So what is the function of leaves? What do they actually do? Are they just there to be pretty or flap around in the wind? Oh, maybe they act as a bit of a wind break.

No, I don't think that's right.

Alex says, "I think the leaves collect sunlight." Aisha says, "I think the function of leaves is gathering water from the plant." Jacob says, "I think leaves are there to make the plant look nice." Well, I think they could all be right there.

The leaves do kind of face upright to face the sun.

They also go down a bit, don't they, so they could funnel water towards the stem and the roots.

And like Jacob says, well, the plants do look nice with leaves, don't they? They don't look very nice without them.

What do you think here? Are any of the children, right? Who has got it right? Restart when you've discussed that.

Who's got it right? Well, I think I agree with Alex.

The function of leaves is to make food for the plant.

Oh, is Alex, right? How does collecting sunlight make food for the plant? What do you think the leaves need to make this food then? Hmm, discuss.

So what can make the food for a plant? Leaves need sunlight to make food for the plant.

Many plants have leaves that can move and catch the most sunlight possible.

They don't scoop the sunlight outta the air.

It's a little bit like big solar panels facing up at the sun, collecting it all in.

And does that mean that they scoop the sunlight up? What happens? Leaves also need carbon dioxide to make food.

Carbon dioxide is a gas in the air around us.

We can't see it or smell it or taste it, but it is always there.

Here you can see some leaves.

These look like ivy leaves.

They look very shiny, don't they? Leaves also use water, which is absorbed through the roots to make food for the plant.

The process of making food, using sunlight, carbon dioxide, and water, is called photosynthesis.

Have you ever heard that word before, photosynthesis? What does it mean? What does photosynthesis do? Hmm, let's stop and think first, what do leaves use to make food for the plant? Do they use water, oxygen, carbon dioxide, light, or soil? The correct answer here is water, carbon dioxide, and light.

There were three possible answers there, of course.

Laura says, "My dad uses this plant food for our plants.

Does that mean that they don't need leaves to make their own food?" Hmm, what do you think, the plant food is there to help the plants, or does that replace the leaves entirely? Discuss.

So, what did you think? Does the food replace the leaves? Plant food that we can buy in shops is a type of fertiliser.

We can add fertilisers, which contain nutrients, to soil to help plants grow.

Here you can see an example of some plant food.

You may have seen a similar bottle like this.

However, plants don't get their food from the soil.

So fertilisers don't actually feed them or provide food.

Laura says, "Well, what a confusing name.

So that means that plants still need to make their own food in their leaves using photosynthesis, even if we give them fertilisers?" Yes, it is rather confusing, isn't it? I wonder how we can help Laura best understand this.

So that is plant food to help them grow, but it's not actually food, hmm.

Hopefully we can find out some more.

Stop and think first.

Where do plants get their food? Is it given to them by humans, is it sucked up through the roots, or is it made inside the leaves? The core's answer here is it is made inside the leaves.

So Izzy wonders what would happen to a plant if it couldn't make food in its leaves.

Sophia says, "Well, I think it would die, because it needs food to survive." Jun says, "I think maybe the stem or flowers would start making food instead." And Lucas says, "I think it might grow more leaves, because it needs them to survive." What do you think? What would happen if we removed all the leaves? Restart the video when you've discussed that.

So what would happen if it couldn't make food in its leaves? We can find out more about plants and their leaves by carrying out an observation over time investigation.

Izzy decides to carry out an investigation to answer the question, "What would happen to a plant that can't make food in its leaves?" If a plant makes food in its leaves using sunlight, carbon dioxide, and water, how can Izzy stop a plant from making food? Lucas says, "Well, we could take off all the leaves." Sam says, "We could cover the leaves in tinfoil, so it won't be able to get sunlight to make food." Ooh, those are both very good ideas.

I wonder what Izzy decides.

She says, "I'm going to remove all of the leaves from a plant to stop it from making food, and observe over time what happens." Alex says, "How will you know if it grows any differently to a plant with all of its leaves?" What do you think? Is there a way to compare? Restart the video when you've discussed that.

So what did you discuss? Let's see if you were correct.

Izzy decides to get another plant of the same type, but keep all of the leaves on.

She'll give them the same amount of sunlight and the same amount of water, and keep them both in the same type of soil.

This way she can compare the difference between a plant with leaves and a plant without leaves.

Stop and think.

Why is Izzy observing another plant with leaves, as well as the one with no leaves? Read each statement, and decide which one best fits the answer.

The correct answer here is so she can compare the difference between both plants.

Izzy has set up her investigation.

There's her investigation there.

There's two pots and there's two plants.

She needs now to decide when she's going to make her observations.

Oh yes, I can see one of the plants there doesn't have any leaves at all, does it? What do you think though? When is she going to need to make her observations? Plants take time to grow and to change.

So her observations will need to be taken over days, or even weeks.

Izzy says, "I'm going to observe the plants every week for three weeks.

What will I need to record each time?" What do you think? What is she going to record? So what do you think? Laura says, "You could take photos of the plants to show how they're changing." Jacob says, "You could measure the height." Jun says, "You could write a description of each one." And Andeep says, "You could draw a diagram of each plant." I wonder if any of these children are right, and I wonder what you decided.

Let's find out more.

Stop and think.

We can find out more about the function of leaves by removing the leaves from a plant and blank it over time.

Observing it, watering it, or researching it? Decide.

The correct answer here is observing it over time.

Here is task B.

Make a prediction about what will happen to a plant that can't use its leaves to make food.

I think a plant with no leaves will, what, because, why? Have a think.

Restart the video when you've done that.

I wonder what you decided.

It could be similar to this.

Izzy says, "I think it will die, because it won't be able to use photosynthesis to make food, and it needs food to survive." Laura says, "I think it will slowly grow new leaves, because plants need leaves to make food.

If its leaves are removed, it won't be able to make its food, so it will need new leaves." I wonder if your prediction was similar to theirs.

Here's the second part of task B.

Set up your investigation.

Make a plan so you know when you'll need to make observations over time, and what you will record.

So you are going to need to have a good think here about how you're going to plan this, and what you are going to do.

Think about your variables, think about what you're going to keep the same.

Have a go during that task, and restart when you've done that.

How did you get on? Maybe your answer is similar to this.

Izzy said, "I decided to make observations every five days, and write down a description of how each plant looked." Lucas says, "I'm going to take photographs of the plant and add a note about how tall each one is every week." Sam says, "How did you decide to make and record your observations?" Is it similar to these children here, or did you think of something entirely different? Well, I'm sure that you've had a good plan for your investigation, so best of luck.

The final part of this lesson is called what happens to plants with no leaves? Lucas says, "I took photos of my plants each week so that you can see the results.

These are my plants at the start." So the first picture there is plants that had leaves removed, the second one is a plant that had leaves left on.

And here are the two plants after 10 days.

He says, "What can you observe about the growth of the two plants?" Hmm, have a good look at these two pictures, and decide what can you observe about them? Restart when you've done that.

Now, here are a picture of the plants after 20 days.

What can you observe? Restart the video when you've done that.

Wow, there's a real difference there between the photos at the very, very beginning, and the photos at the end here, isn't there? I wonder what you've noticed here.

Have you noticed the same thing that I did, in the fact that the plant that didn't have any leaves has actually grown some more by the end? How amazing.

Plants are fascinating things, aren't they? Even though one of them has had a real disadvantage there, by losing all its leaves, eventually it was able to actually grow some new ones to enable it to be able to get some more sunlight.

Stop and think.

Plants grow better when their leaves are removed.

True or false? Use your observations from the pictures to decide.

The correct answer here is false.

They don't grow better when their leaves are removed.

Let's justify our answer.

Which of these statements best matches? The correct answer here is A, plants use their leaves to make food, so they can't grow well without them.

Here's the final task for this lesson.

Use the observations you've made of your plant to, part one, describe what happened to the plant that had its leaves removed, and, part two, explain what happened.

So why did this happen to the plant that had its leaves removed? Good luck with your task.

Restart the video when you've done that.

How did you get on? Well, your answers could have been similar to this.

The plant that had its leaves removed slowly grew some more leaves.

Plants use their leaves to make food.

If the leaves of a plant are removed, it can't make as much food.

It grows more slowly until it has grown new leaves.

That is hopefully what you observed from those pictures as well.

The plant that didn't have any leaves had eventually grown some of its own.

What a marvellous thing for a plant to be able to do.

So even if plants lose their leaves, they can slowly grow some more to enable them to make their own food again.

Let's summarise our lesson.

Many plants have roots, stems, leaves, and flowers.

Plants can make their own food.

This happens in the leaves of the plant.

Plants make food in their leaves using sunlight, carbon dioxide, and water.

To investigate why plants have leaves, a plant with leaves removed can be observed time, just like the experiment that you were able to observe there.

And I hope that you were also able to have a go completing that experiment too.

Plants are really amazing things, aren't they? So that plant there, even with its leaves removed, was able to start regenerating and growing again.

Plants are really fascinating.

I hope you found that fascinating in this lesson as well.

I be Mr. Wilshire.

Thank you very much for listening.