Lesson video

Hello, scientists.

My name is Mr. Wilshire and in this lesson we're going to be looking at what plants need.

This is the planning stage.

The outcome for this lesson is: I can ask relevant questions about what plants need and plan a fair test to answer them.

As always, there are some keywords for us to remember throughout this lesson.

The first is plant, next is conditions, after that, requirements, then it's comparative test, and finally, variables.

Don't worry if you can't remember what all of these words mean.

The definitions have appeared on the screen for you now.

So if you need to, you can pause the video here and recap before you move on.

Pause the video now if you need to and continue when you are ready.

The first part of this lesson is called What Plants Need.

Jacob observes that one of the plants in his kitchen doesn't look very healthy.

Do you have any plants at home? I wonder if ever they've looked a bit like this.

I know my plants sometimes do this as well.

Jacob says, "What's wrong with my plant?" Alex says, "I think it's dying." Jun says, "Plants can't die because they're not alive.

Maybe it's broken." What do you think? Are any of the children right here? Is something wrong? Is the plant dying? Are they alive? Hmm? Discuss.

So what did you discuss? Are plants really alive? Is this plant dying? Let's find out more.

Plants are living things.

Here's some examples of plants.

There's a tree and a plant with raspberries on.

There's purple flowers, and also one with lots of leaves as well.

Plants all need the right kind of conditions to grow and to stay healthy.

The things that plants need are called their requirements.

Hmm.

I wonder what kind of requirements plants actually need? Stop and think.

Which of these statements about plants is incorrect? Plants are living things.

Plants can survive in any conditions, or plants need the right conditions to survive.

The correct answer here is B: Plants can survive in any conditions.

Alex's dad has some tiny pea shoots that he'd like to grow into larger, healthy plants.

There's Alex, look, and there's Alex's dad, and there's an example of the pea shoots.

They're very small, aren't they? Just poking up through the top of the soil.

I wonder what requirements the plants will have to survive and to be healthy.

Hmm.

What do you think? Pause the video here and have a think.

Restart when you've done that.

So what kind of requirements are these plants going to need to survive? Let's find out more.

The requirements for plants to grow and stay healthy are: I wonder if you've got some of these.

Oh, there's lots of them.

Water, air, light, nutrients from the soil, room to grow, warmth and, hmm, anything else that we are missing? Have you thought of anything extra? Alex's dad is going to need to make sure that the plants get all of these things to grow and to be healthy.

He plants the shoots in soil, giving each one its own pot so that they have room to grow.

So he's been able to dig them up there, plant them into a pot each, and then get ready to grow them.

So there's nutrients from the soil there.

Good.

That's the first one of the list ticked off.

There's room to grow.

That's another part we've ticked off there.

Each of them have got their own pot, their own little space.

He then puts them in a warm place with plenty of sunlight and air, and then he waters them regularly.

So make sure that he waters them, although not too much or otherwise they might drown.

Looks like they're in the window there.

So they've got lots of light as well.

How fantastic.

They've got air as well.

Air is everywhere really, isn't it? And of course, the water that he's adding now.

Also because they're inside, they're going to be able to keep warm.

Sometimes gardeners will do this if they want to start growing plants in the wintertime, so that the shoot can shoot up from the pot in the nice, warm house.

It gets sunlight through the window and you can keep watering it.

And then when it's not cold outside anymore, you can take the plants outside and replant them.

Stop and think.

Which of these is not a requirement for plant growth? Is it air, water, a plant pot, room to grow, or nutrients from the soil? Which of these is not a requirement? Did you get it right? It's a plant pot.

You could plant a plant anywhere.

It doesn't have to be in a pot.

Lucas says, "What would happen if a plant did not have one of these things?" Hmm.

So if it didn't have water or air, or light, nutrients from the soil, or room to grow, or even warmth, I wonder what would happen? What do you think? Pause the video here and discuss.

Restart when you've done that.

So what did you think? What's going to happen if a plant doesn't have one of these things? Let's find out more.

Scientists can investigate what plants need by taking away their requirements and then observing what happens.

Here's a plant scientist.

So we are going to ask a scientific question here about plants and their requirements.

Then we're going to carry out our very own investigation to try to find an answer.

That's the reason why we do experiments, isn't it? Stop and think.

Scientists can investigate what plants need by blank plant growth when requirements are taken away.

The correct answer here is observing plant growth.

They need to observe what is happening first, don't they? Here is Task A.

The first part is to decide which of the plant requirements you are most curious about and complete this question: How does having no blank affect plant growth? So decide which one of the important things are you going to take away? Are you gonna take away the warmth? Are you going to take away the nutrients in the soil? Are you going to remove water? Or maybe you're going to remove the light? I wonder how taking one of those things away is going to affect it.

Complete the question and then do part two: predict what you think will happen to the plant that has had a requirement taken away.

So maybe if you think that removing all the light is going to make the plant grow lots or grow not at all, then you can write that down, that's your prediction.

What do you think is going to happen? Good luck with that task.

Restart the video when you've done that.

How did you get on? Hopefully you've had a good chance here to think about what requirement you're going to take away.

Here's some example ones.

Yours might be slightly different.

Aisha says, "My question is, how does having no light affect how a plant grows?" Sofia says, "Mine is: how does having no nutrients from the soil affect how a plant grows?" And Andeep says, "What was your question?" Was it similar to these or was it different? Part two here says that you needed to predict what you think would happen.

So thinking about your own question, not just the ones that we've given you.

Aisha says, "I think the plant with no light won't grow at all.

It'll just die." Oh, that's a shame.

Sofia says, "I think the plant without nutrients won't have any leaves and will be all floppy." Oh, okay.

That's another way of thinking about it.

We're not just thinking about whether the plant is going to die or not.

We're actually trying to think about what's going to happen.

Maybe it would grow to be a different colour, or maybe it's going to go at a very, very slow rate.

Andeep says, "What do you predict would happen?" Well, with your questions, I hope you've been able to predict what you think is going to happen.

Remember, your prediction doesn't need to be correct, it's just about what you think could happen, any possibility.

The second part of this lesson is called Planning a Comparative Test Investigation.

Scientists can carry out comparative test investigations to find out more about how plants grow.

So what do you know about comparative test investigations? Here's Lucas and he's going, "Hmm?" What do you think? What do you know about a comparative test investigation? Have you ever heard that word before? Break it down and have a think.

What could it mean? Restart the video when you've done that.

So what do you know about a comparative test investigation? Let's find out more.

When we carry out a comparative test, we change one thing that we are investigating.

We measure one thing and we keep everything else the same.

The things that we change, measure and keep the same are called variables.

The first thing we need to do is identify the variable, the thing that we are going to change, and that is going to affect our results.

Remember, you are only going to change one thing.

In this case, in this investigation, you are changing one of the conditions a plant needs to grow.

So what are the things or variables that could affect the way a plant grows? Have a quick think.

Have you been listening so far? We've mentioned it a few times.

Discuss.

So what did you think of? What are the things or the variables that could affect the way a plant grows? Hopefully you said one of these things: The volume of water it gets, the type of soil it's growing in, the brightness of the light that it gets, the amount of room that it has to grow, the temperature that it's growing in.

And anything else? Maybe you've thought of something here that we haven't.

The volume of water.

Well, you could either take all the water away or you could maybe give it way too much.

The type of soil.

You could change the soil, couldn't you? You could dig some up from the front of the school and then some up from the field in the school, maybe even try growing it in sand.

The brightness of lights.

You could grow one plant outside and one plant inside, maybe even one in the cupboard.

The amount of room that it has to grow.

Well, you could try one in a very big pot and one in a tiny pot.

And the temperature it's growing in.

You could put one outside and one inside.

If there's one place that you could choose, maybe you would grow one next to a radiator and see if that helps.

To see how changing only one variable affects our plant, we'd need to keep all the other variables the same.

This way we know that any changes to plant growth are caused by the variable we changed and not anything else.

Here you can see two children observing some plants there.

Lucas has a question about plants to investigate.

He says, "How does having no light affect how a plant grows?" So he's going to give one plant all of its requirements and another plant everything except light.

Then he can compare the plants with each other.

So what variables will he have to keep the same for both plants? Pause the video here and have a discussion.

Restart when you've done that.

So what variables is he going to have to keep the same for both plants? Lucas says, "I will need to make sure that both plants are growing in the same amount and the type of soil, I need to get the same volume of water and have the same amount of space to grow.

I will keep them in the same room so they are both growing in the same temperature and both will have access to air." Okay, excellent.

Those are the things that he's keeping the same.

Stop and think.

We can carry out a blank test investigation to find out about requirements for plant growth.

The correct answer here is "comparative".

We can carry out a comparative test investigation to find out about requirements for plant growth.

In a comparative test investigation, two variables are changed and everything else is measured.

One variable is changed, one is measured, and the others are kept the same, or the variables should be shared out fairly between plants.

Which is the correct answer here? In a comparative test investigation, one variable has changed, one is measured and the others are kept the same.

Izzy has a question about plants to investigate.

She says, "How does having no water affect how a plant grows?" The variable that she is investigating is water.

So which variables will she need to keep the same for both of her plants? Have a think here about the conditions that plants need to grow.

Restart when you've done that.

So which variables is she going to need to keep the same? She says, "I'm gonna put both of my plants on a sunny windowsill so that they have light and air and will be at the same temperature.

I'm going to put them in the same size pots.

I'll plant one of them in soil and water it every two days, then I'll plant the other one in sand and give it no water." Hmm.

What do you think of Izzy's plan? Has Izzy made any mistakes? Discuss.

Has Izzy made any mistakes? What did you spot? Andeep says, "If you put one in soil and one in sand, you won't know if any differences to the plant have been caused by not having water or by one plant having soil and the other having sand." Sam says, "You need to make sure that the plant has all of its requirements except for water.

Water is the only variable you will change." Of course, yes.

If Izzy puts one in soil and one in sand, she's changing something.

And then if she doesn't water one and water's the other, that's changing another thing.

You're only supposed to have one thing that changes, one variable.

Stop and think.

Why do we only change one variable in a comparative test investigation and keep others the same? Is it so that we know our results have been caused by the variable we changed? Is it so that there is enough equipment to go around the class? Or is it so that our investigation doesn't take too much time? The correct answer here is A: so that we know our results have been caused by the variable we changed.

Here is Task B.

The first part is to complete the sentences to plan a comparative test investigation.

My question is: what? I will change, what? I will change this variable by doing what? Over the next few weeks, I will observe and measure what? And I will need to keep the same what? Think about your answers to these questions here.

You need to plan the comparative test now.

It's up to you to decide what variables you are going to have.

Pause the video here and restart when you've done that.

So here is an example: Izzy says, "Your answers might be different if you chose a different question to investigate." The question is, how does having no light affect how a plant grows? They're going to change the amount of light.

They're gonna change that variable by keeping one plant on a sunny windowsill and another inside a dark cupboard.

They're going to observe and measure the height of the plants and how healthy it looks.

And the thing that they need to keep the same is the water, the nutrients from the soil, the air, room to grow and the temperature.

Excellent.

That's a really good plan.

So complete this table to explain how you're going to keep each variable the same.

Think about each variable: air, water, light, warmth.

How are you going to keep them all the same? Pause the video here.

Restart when you've done that.

How did you get on? Here are just some examples.

Your answers could have been similar.

So with the water: I'm gonna water both plants every two days.

Oh, and 20 millilitres as well.

It's really important to measure it.

Nutrients from the soil: I'll put both plants in the same amount and type of soil.

The air or the temperature: both plants are gonna be in the same place.

The light: again, both plants will be in the same place, on a window where they're gonna get the same amount of sunlight.

And room to grow: they're gonna have the same amount of plants with the same amount of space in the same size pots.

Excellent.

All of those things are the same and only one thing is going to change.

Hopefully you were able to plan your investigation and think about each of the variables here.

I hope that you've taken some consideration into the type of thing that you're going to change and how long it's going to take you to observe this.

Some experiments can take a very long time, so I hope that you've given yourself some time and put your experiments in a safe place so you can observe it over that period of time.

Let's summarise our lesson: Plants are living things.

They need the right conditions to grow and stay healthy.

They need air, light, water, nutrients from the soil and room to grow.

We can investigate plants requirements for growth with a comparative test investigation.

In a comparative test investigation, most variables must be kept the same so that only one thing is changed.

Well, I hope you've been able to plan some investigations and think about the different variables that you could use.

Hopefully this is gonna inspire you to do some different investigations.

It doesn't just have to be about plants.

I wonder what else you'd choose? My name's been Mr. Wilshire.

Thank you very much for listening.