Lesson video

Hello and welcome to today's lesson from the Unit: Growing Plants.

This lesson is called Plants Without Water.

Hi, I'm Mrs. Waller.

In this unit, we've been finding out what plants need to grow and stay healthy.

By the end of this lesson today, you are able to find out and describe what happens when plants do not have water.

Let's take a look at the keywords that we'll be using today.

Plant, water, survive, compare and record.

Take a moment to think about these words.

Do you know what any of these mean? Don't worry, if not, by the end of the lesson today, you'll be a complete expert.

Today's lesson is in three parts.

The first part, we will be observing the plants that have been growing with no water.

In the second part, we'll be thinking about what happens to plants with no water.

And in the third and final part we'll be learning about how much water do plants need.

Plants are living things and all living things need water to stay alive and keep healthy.

Let's take a look at some examples.

Here's an example of a human drinking water.

I'm sure everybody knows what it feels like not to have had a drink for an amount of time and to know how much our bodies depend on water.

We're now thinking about other types of animals.

This Impala is a mammal and it's usually found in southern or eastern Africa, and it's shown in the picture here, taking a drink of water from a lake.

So those are animals, living things.

Don't forget the plants are living things too and we know that also plants need water.

I'm sure you've all been involved in watering some plants at some point in your life.

Plants definitely need water to grow and to stay healthy.

What other living things can you think of that need water? Let's think about the roots of a plant.

Now they have a very important job.

If we look at this photograph of a plant that's been taken out of its soil, you can see the roots that are hidden down under the ground or in the plant pot.

The roots take up water and good things that the plants need from the soil.

The water that's taken up by the roots then travels all around the plant and helps to keep it healthy.

Are you ready for some questions so that I can check your understanding of what we've learned so far? A bird is a living thing.

What does a bird need to grow and stay healthy? Toys, eggs or water? Yes, that's right.

All living things need water.

My second question, which statement below is true? All plants need water to survive.

Only some types of plants need water to survive, or plants do not need water to survive.

Well done.

All plants need water to survive.

Now have a think about this one, it's a true or false question.

What do you think? The fake grass, made of plastic, I laid in my garden needs water to stay healthy? Is that true or is that false? And the answer is, it's false.

Now let's have a think about why it's false.

So take a moment to gather your thoughts.

You might want to write your ideas down or you might want to talk about your ideas with somebody.

Why do you think the plastic grass does not need water? Have you got some good ideas, you might want to choose out of these two suggestions.

Plastic grass does not need water or all grass needs water.

What do you think? Yes, that's right.

Grass made from plastic is not a living thing, therefore it does not need water.

We're thinking about our science question for this lesson.

What happens to plants when they do not get what they need? And in particular, today, we are going to be observing the plants that have been growing with no water.

Take a minute to think.

What do you think will happen to our plant with no water? Now it's time for our first practise task and it's the time that we've all been waiting for.

It's an opportunity for you to make an observation to go and observe your plants that have been growing with no water.

And also, to observe the plants that have been growing with water, warmth and light that have had everything that they need, so that you can compare your plant that's been growing with no water to your plant that's been growing with everything.

Don't forget to think about, talk to somebody about this.

What does a healthy plant look like? Remember these things.

Usually healthy plants have tall, strong stems. They have green shiny leaves.

Is there anything else that would tell us that a plant is healthy? Now, you will need to remember this when you are making your observations so that you can say whether the plants in this investigation are healthy or unhealthy.

Pause the video and take some time to make your observations.

Now that you've made your observations it's time to record the results of your investigation for plants with no water.

So we have our chart where we've been recording our results.

And don't forget, we've already put in our photographs of the plants at the very start and we've already added our results of our plants after one week of the investigation so that we could remember what the plant looked like that had no water and what the plant looked like that had continued to grow with everything.

And in this lesson today you're going to be recording your endpoint your final observations, what has happened to your plants, the plants that have been growing with water taken away and the plants that have continued to grow with everything that they need? Now don't forget the chart that I'm using is just one way of recording, you might have different ideas.

So by now you should have made your plant observations and recorded your plant observations.

I'm going to show you what's happened to the plants that I've been growing.

Are you ready? Oh my goodness.

(Mrs. Waller laughs) Oh, is this something that we were expecting? Look at our poor plant.

It's been growing with no water at all.

What on earth has happened to our plant? Here is a photograph where we are able to compare our plant that's been growing with everything, so it has been given water.

What a difference.

Look really carefully at my photographs and think about what happened to the plants in your investigation and what do you notice? The first thing that I can see is our plant that's been growing with no water is almost certainly wilted.

So it's gone floppy and droopy and the stem has not been able to continue to grow in an upright position.

Some of those leaves look like they've dried out and gone shrivelled a little bit smaller, they look a bit wrinkly, don't they? And if we compare that to our plant that's been growing with everything that it's needed, wow, it's tall, it's healthy, it's green, it's got plenty of leaves on it.

In fact, if we compared, if we could count how many leaves are on the plant with everything to the number of leaves on the plant that's been growing with no water you'll see a real difference.

So I'm going to add these photographs into my chart to record today's observations of plants growing with no water compared to plants growing with everything.

And here are the results so far.

All I've got to do today is just add in our final images.

Oh, so we can really see the difference here of this plant at the very start.

And then after one week of having water taken away from it, and now at the end of the investigation.

This investigation is all about comparing, making comparisons.

So if we compare our plant to the plant that was growing with everything that it needs I've just popped that one there into our chart of results.

So this is the end now of our no water investigation and we've got lots of things to think about and talk about.

Don't forget to look at your own results from your own plants that you've been growing.

Are your results similar or different to mine? And now we're moving on to the second part of this lesson where we're really thinking more about what happens to plants with no water? We know that plants need water because water travels up the stem of the plant and it helps it to stand upright and strong and tall.

When a plant does not have water a plant will become floppy and it starts to wilt.

By observing plants, we can see that the leaves of a plant with no water can dry out and become dull, crispy, sometimes even brown.

The leaves or flowers can also fall off the plant.

So take a look at these photographs of plants with flowers that were grown.

This one was grown with water and this plant was grown with no water.

Take a moment to observe the differences and maybe describe to someone else what you can see about the healthy plant and the unhealthy plant.

You might notice the wilting stem.

That's certainly the first thing that I noticed.

Have any of these happened to your plant with no water? We're moving on to some check for understanding questions now.

Another true or false question.

A plant with no water begins to wilt.

Is that true or false? Yes, that's definitely true.

If we think about those photographs that we've just seen a plant with no water will begin to wilt.

Let's think about how we know that or why we think that.

Maybe make a choice out of these two statements.

Water helps the stem of a plant to stand tall and strong or water helps the roots of a plant to stand tall and strong.

Which one do you think? Well done.

Yes, it's the stem of the plant, isn't it? That stands upright.

And it's the stem of the plant that we can see floppy and wilting on the plants that we've observed.

Moving on to another question now.

We know that counting the leaves of a plant is one way of helping us to observe how healthy a plant is.

So let's take a look at this table of results.

We've got two plants.

We can see plant A and plant B.

And what we've done is we've counted the number of leaves on each of the plants in week 1 and week 2 and week 3 and week 4.

So you can see that in week 1, plant A had 1, 2, 3, 4 leaves.

And also in week 1, plant B had, that's right, 1, 2, 3, 4 leaves.

So if we count the leaves of the two different plants we can maybe make a decision about whether the plant is a healthy plant whether it's kept its leaves or whether it's continued to grow more leaves, or maybe an unhealthy plant might have dropped some of its leaves, some of its leaves might have fallen off.

So what I'd really like you to think about here is which plant do you think had no water? Look at the table of results and can you explain why? So the plant that had no water do you think it's plant A or do you think it's plant B? Take a moment.

And the correct answer the plant that had no water, is plant B.

Now can you explain why? Here's the tricky part.

If you look at the number of leaves on plant B, it starts with four leaves, and then in week 2, it has three leaves.

And then in week 3, it has two leaves.

And then by the end of week 4, it only has one leaf left on the plant.

The leaves must have dropped off, because that was the plant that wasn't getting water.

Did you get that one? Well done, it was a tricky one.

Moving on to our practise tasks now.

Talk to a partner about what you have found out about what happens when plants grow with no water.

Now you might remember back in lesson 3, you asked to draw your ideas or to write down your ideas of what a healthy and an unhealthy plant looks like.

So maybe you could look back at those drawings and those ideas to see if you were correct.

It would be brilliant if you could draw another picture or write another description telling us what does happen to plants when they do not have water.

So think about everything that you've learned today in today's investigation, your observations, what you've recorded.

Bring all of that information together and you could draw me a picture or you could write me a description of our unhealthy plant that has not had water.

So here's an example for you to have a look at.

We have a fantastic drawing of a plant with no water.

Oh my goodness, what do we notice? It looks dry, it looks droopy.

That means it's wilted, it looks crispy.

And this plant in particular has gone brown in colour.

And our description, if we were writing about it might be when plants do not have water, sometimes their leaves can turn dull, crispy and brown, leaves are droopy and can drop off the plant.

The stem can no longer stand tall, so it wilts.

Have a think about this practise question.

Laura grew some plants from seeds.

Each week she used a ruler to measure how tall they had grown.

So we have plant A and plant B.

And you can see here that in week 1, Laura used her ruler and she measured plant A to be one centimetre tall and plant B to be one centimetre tall.

Take a look at the rest of the results.

Have a look at how tall plant A and plant B was in week 2 and week 3 and week 4.

You'll notice that after two weeks she stopped giving water to one plant.

Which plant do you think had no water? And why do you think this? It would be great if you could talk to somebody about your ideas.

Do you have the same ideas as me? Plant A and B, were the same height after two weeks? Yes, you can see in the table of results in week 2, plant A was three centimetres and plant B was three centimetres.

And what happened after that? Well, plant B kept growing taller.

It grew to seven centimetres and then it grew to 10 centimetres, didn't it, by week 4? Let's have a look at plant A.

"I think that plant A was wilting, because it had no water." Is that the same as what you thought? We're moving on to the final part of this lesson now, and we're going to be learning about how much water do plants need.

We know that lots of plants need water every week.

For example, plants that you might keep inside, plants in the garden or plants in the park and crops.

Now crops are where lots of plants are grown at the same time, quite often to be sold and sometimes for food.

Different plants can survive without water for different amounts of time.

I'm going to give you some examples now.

We know that some plants grow in very dry parts of the world.

This jade plant grows well in countries such as Mexico and South Africa and we know that it's very hot and dry there, but the plant still grows well and remains healthy.

So how does it do that? Take a look at the photograph of the jade plant and have a look at its leaves.

Do you notice anything a little bit different about them? You might see that it has very thick leaves and these thick leaves help to store the water for a long time.

Do you remember how the water travels up from the soil through the roots into the plant and then all around the plant to keep it healthy? Well, the thick leaves help the jade plant to store the water and stop it from drying out when it's very hot and it's very dry.

How about this cactus plant? Now, most people think of a cactus as a plant that grows in a desert where there's very little or no rain at all.

And people quite often think that a cactus does not need water at all.

Well, it still does need water.

It's a very clever plant because it stores water like the jade plant.

It stores water for a long time.

It's got this really thick fleshy stem so you can see where the arrow is pointing to, and that's the stem of the cactus plant.

Now, the cactus also has very long roots that go deep down under the ground to collect water from far down so the roots grow further down in order to collect water.

Can you think of any other plants that can survive for a long time without water? We know that plants can become unhealthy very quickly and that's if they've had too much water and also if they've not had enough water.

And here's the photograph again of the plant that I've been growing that had no water and it certainly does look unhealthy.

But here's a question for you.

What do you think you could do to help a plant that has been growing with no water? So take a look again at the photograph of my plant do you think that there's anything that we could do to the plant and can it become healthy again? I have some questions for you to check your understanding of this final part of the lesson.

All plants need water every day.

Do you think that's true or false? Yes, that's right.

It's false.

And I'd like you to think about why do you think that? So just gather your thoughts in your head.

"All plants need water every day.

False, I think this because.

." what information do you know that can help you to answer that? So do you think it's because different plants need different amounts of water? Or do you think that some plants never need water? Yes, that's what we've been learning, A, that different plants need different amounts of water.

And even though that there are some plants that don't need water very often, they still do need water to grow and to stay healthy.

Now have a think about this one.

There is a tree called the Shepherd's tree and it grows in South Africa where it is hot and dry.

The roots of this tree are rather special.

The roots can grow down as far as 70 metres.

Now, if you did a big stride from one foot to the other, the biggest step that you can take that's probably about one metre.

So think about taking 70 steps down the street or across the school playground.

And can you imagine the Shepherd's tree roots growing as far down into the ground as that? Now we've got two ideas here and I want you to think about who do you agree with and why? So Sophia thinks the roots grow long into the ground where it is cooler.

And Jacob thinks the roots grow long to find water deep down in the soil.

Who do you agree with and why? Yes, that's right, Jacob.

The roots grow down rather like the cactus plant deep down into the ground to find water so that the plant can continue to grow and stay healthy.

Moving on to our final practise tasks now.

So you've been growing a plant that's had no water for several weeks and I want you just to touch the soil around that plant.

Does it feel dry? What do you think will happen to the plant if you add water to the soil now? Could you record your ideas? You could maybe draw a picture of what you think will happen to the plant after water has been added.

Or you could write.

You could write a description of what you think will happen to the plant.

And the final part of this practise task is to give it a go.

Get a watering can or a water spray and add some water to the dry soil around the plant that's been growing with no water.

And I'd like you to observe what happens to the plant over the next few days.

You could talk about your ideas with somebody.

What do you think is going to happen? Is it possible for this plant to become healthy again? We've got some ideas here.

Maybe you could think about who you agree with and why.

"I think when a plant is dry and wilting it is dead and it cannot be made healthy again." Do you agree with that one? "I think water will make the plant green and healthy again." So that's a different opinion, isn't it? Who do you agree with? Or maybe you have some different ideas.

We've reached the end of this lesson now and it's time for you to think about what you know that you didn't know at the start of the lesson.

So plants are living things.

We know that they need water to grow and stay alive and keep healthy.

But what else do you know now? I would say that we definitely know that plants without water can become dull and dry and wilted.

And finally, we know that some plants such as cactus can survive for longer without water.

To complete this lesson, have a go at the exit quiz.

Remember to think about everything that you've learned today and I will see you next time.