Hello, everyone, and welcome to today's science lesson.

My name is Mrs. Waller and I'm really looking forward to learning more with you today about simple forces, including magnets.

Today's lesson is called "Different surfaces: do and review." The learning outcome for today's lesson is I can carry out tests and compare how things move on different surfaces.

So you may remember having carried out some planning, and in today's lesson you're going to be following your plan to actually carry out your tests and find answers to your question.

We have a number of keywords that we'll be using in the lesson today.

Surface, friction forces, rough, smooth, and conclusion.

You may have heard some of these words before.

I'm going to very quickly show you the keyword definition slide.

Have a quick read down at some of these keyword definitions, or you might want to wait and go back to this slide later on in today's lesson.

Now don't worry if there's any words here that you haven't heard before or you're not sure about.

All of these words we're going to be learning about today so you will be keyword science superstars by the end of the lesson.

Today's lesson is in three parts, and in the first part of today's lesson we're going to start by comparing different surfaces.

Let's get started.

So we're going to begin the lesson by thinking about what a surface is.

Now surface is one of our keywords today, and you'll have heard this word before I'm sure.

Do you want to spend a little bit of time just explaining to a partner what do you think a surface is? I'll give you five seconds.

Well done, everyone.

So you've got your ideas together.

Well, we know that a surface is usually the outside layer or the top layer of something, and we know that objects move differently over different surfaces.

So, for example, you might think about how objects move over a smooth tarmac road, and you might think about how that's different to how objects move over something that's quite a different surface.

In this case, a rough stone path.

So you may have been in a vehicle driving along a smooth road before, and you may have been walking or you may have gone on a bike across a rough stone path, and you will have definitely have thought about how different these surfaces are for you to move across.

And this shows us that some surfaces are easy to move over, but others are difficult.

Take a look at the examples here of these cars.

We have a car driving on a surface of ice compared to a car driving on a surface of sand.

Do you think cars move in the same way on ice and sand? And why do you think this? Take a moment to have a think.

We know that ice is usually a smooth, slippery surface and we know that sand can be rough and bumpy to move over.

So I think that the cars would definitely be moving in a different way.

I think objects move very easily and quickly over ice, a little bit too fast sometimes, don't you think? But we move and objects like cars move very differently over rougher, bumpier surfaces like sand.

In this lesson today, we are helping Izzy to compare how a marble moves over different surfaces.

And here's Izzy with her question.

"Does the type of surface a marble rolls on affect how far the marble moves?" Hmm, very interesting question.

So Izzy's not thinking about cars moving over surfaces or people moving over surfaces.

This time, she's thinking about how a marble rolls across different surfaces and she's thinking about how the type of surface might affect that.

So Izzy is going to carry out a comparative test investigation, because these types of investigations can be carried out to compare how different surfaces can affect how things move.

We know that we often use comparative test investigations when we are comparing two or more things in a fair way.

And in the case of this investigation, the thing that Izzy is changing is the type of surface.

So we know that the type of surface can have labels.

It could be tarmac, it could be ice, it could be sand.

So Izzy's going to use a comparative test so that she can compare the different surfaces and find out how different surfaces affect how far the marble moves.

Are we ready to help Izzy with her comparative test investigation? I definitely am.

Let's do a couple of quick checks for understanding before we do.

Which of these statements below is true? Is it A, objects move differently over rough and smooth surfaces? Is it B, objects move in the same way over rough and smooth surfaces? Or is it C, all objects move in the same way if you give them the same push? I'll give you five seconds to think about this carefully.

Have you decided? And the answer is A.

Yes, we know that objects move differently over rough and smooth surfaces, and that's what Izzy is gonna find out by rolling her marble over some rough and some smooth surfaces, and she'll be able to collect some data to be able to show that.

Our second check for understanding.

Scientists can carry out, and there's some missing words here, to compare two or more things.

Have a think about it, what type of investigation might this be? And the answer in this case is comparative test investigations.

Well, there's three words to fill that gap, isn't there? Did you get that? Comparative tests or comparative test investigations.

Well done, everyone.

Let's move on.

In this investigation, does the type of surface of the playground affect how far a ball rolls? Which of these things are being compared? So are we comparing different surfaces or are we comparing different balls? Let's go back to the question one more time.

Does the type of surface of the playground affect how far a ball rolls? I'll give you five seconds.

And the answer is A, and the clue is usually in the question, isn't it? If we go back to the question and it says, does the type of surface of the playground affect how far a ball roll? So we are actually comparing the types of surfaces.

We use the same ball and we'll roll it across different types of surfaces, so that's the thing that we're comparing in this comparative test.

Okay, so we have our first practise task here and we'd really love it for you to have a go at this investigation.

So if you've already formulated a plan, you've got your own plan that you want to follow, so when you set up your test, it might look like this.

So here are Izzy's ideas here on the screen and Izzy's using half a kitchen roll tube and she's stuck that to a ramp.

So how she made her ramp, she's taken a book, and she's just propped that kitchen roll tube up at one end to make a ramp and she's gonna put the marble in the top of the tube at the top of the ramp and the marble will roll down the tube.

That's a good idea, isn't it? And onto the surface.

And thinking ahead, Izzy is going to place either a long tape measure or a couple of rulers so that she can measure how far the marble rolls.

So your task is to set up your test.

It might look like this or you might have your own ideas.

So to test each surface, hold the marble at the top of the ramp and release it without pushing it.

And what you need to do is measure and record how far the marble rolls.

Don't forget, each time you roll the marble, you need to change the surface.

And keep repeating the test until you've tried out a number of different surfaces so that you can collect your results and you can compare the different surfaces that you've tested.

Now before you start your investigation, you definitely need to think about how you're going to record your results, and you might want to record your results in a table like this.

This table has two columns.

The first column you would need to think about which surfaces you're testing and comparing.

So in this column you might have surfaces such as tabletop, you might have carpet, you might have floor tiles, you might have the pavement outside.

And then in our second column is where you're going to record the distance that the marble rolled.

So you have your tape measure ready to measure in centimetres how far the marble rolled, and record your results there.

Is everyone ready? Let's get started with our investigation.

Well done, everyone.

So Izzy has carried out her investigation and she's measured and she's recorded in a table how far the marble rolled each time using different surfaces.

Here's Izzy's results.

So she's made a record of the different surfaces that she's tested, and she's got carpet, floor tiles, and a tray of sand.

And I think Izzy is still thinking about it, if there are any more surfaces that she might want to test, and you might have tested different surfaces, so this would be where you would record the surfaces that you tested.

And on the second column, Izzy has also recorded the distance that the marble has rolled in centimetres.

And we can see that the marble has rolled 40 centimetres across the carpet.

It's rolled 304 centimetres.

Wow, you'd need a lot of metre sticks for that, wouldn't you, across the floor tiles.

And only 1 centimetre on the tray of sand, how interesting.

Are your results the same or different to Izzy's? We're moving now onto the second part of today's lesson and we're going to be learning about how friction forces slow down moving objects.

Let's move on.

When an object moves across a surface, a friction force is created.

And this friction force acts against the movement and slows down the object.

Well, that sounds a little bit complicated, doesn't it? So should we take an example to help us to understand exactly what's happening? Let's think about this car travelling along the surface of the road.

And if we think about the car tyres, the car tyres are moving in this direction.

So look at the red arrow pointing in this direction on the road surface.

So we know that as the car is travelling along the road surface, the red arrow shows the direction that the car is travelling in.

Now we know that friction forces act against the movement.

So friction forces aren't acting in the same direction, they're acting against this movement, which means they're acting in the opposite direction.

Have a look at the grey arrow.

Now the grey arrow represents friction forces acting in this direction.

And because they're working against the movement of the travelling object, friction forces slow down the car.

Without friction forces, moving objects would never slow down and they would never stop moving.

So without friction forces acting against the movement, the object would just keep travelling and travelling and travelling and travelling and the object would never slow down or eventually stop.

So, actually, in a lot of examples, friction forces can be really useful.

Take a look at this photograph.

What will friction forces cause to happen here? So we have a game of hockey and we're moving the ball across the surface of the ground, hitting it with the hockey stick, and the ball is moving across the surface.

Take a moment to think about friction forces.

Yes, hockey balls hit along the ground will slow down and eventually stop because of friction forces.

How about this photograph? So we've got some inline skates, some roller blades, and the person is skating, moving across the surface.

Where are the friction forces here? Well done, the inline skates will slow down and stop eventually because of friction forces.

And if there was no friction forces, then, if the person was to push off and glide wearing the skates, they would keep travelling and travelling and travelling and travelling and they wouldn't slow down and they wouldn't stop.

But we've got the friction forces acting in the opposite direction.

Let's think about this even more.

When this ball rolls, the surface of the ball moves across the surface of the playground.

So we can see here we've got our red ball with its surface, which is the outer layer, and we've also got the surface of the playground.

And when the ball rolls across the surface of the playground, this creates friction forces between the two surfaces.

And if we were to look really closely, if we were to magnify what was happening, we would see the surface of the playground in contact with the surface of the ball.

And as the ball is rolling and moving across the surface of the playground, where those two surfaces meet, that's where the friction forces are occurring.

Some surfaces create greater friction forces than others, so let's move on to think about that.

We know that some surfaces are rough and the example here is of the rough sandpaper.

Have you ever felt sandpaper before? It feels quite gritty and grainy.

Those little tiny, tiny grains that feel like sand has a rough surface, doesn't it? And how about some surfaces are smooth? And the example here is we have some very polished, smooth stone steps.

Which types of surfaces do you think create greater friction forces? Take a moment to have a think.

It's rough surfaces that create greater friction forces against a moving object.

And it's the smooth surfaces where there is less friction forces.

I don't know if anybody's ever slipped over on a smooth surface where there's less friction.

Yeah, those rough surfaces help us to grip.

A rough surface slows the object down more when it's moving, so you'll be less likely to slip over on a rough surface because there's greater friction forces which helps you to slow down.

Let's move onto some checks for understanding.

True or false? Friction forces slow down moving objects.

Is that true or false? And the answer is true.

Yes, we've just been talking about that one, haven't we? Now why do we think that is true? I think this because, is it A, when I kick a ball along the ground, it eventually slows down and stops moving? Or is it B, when I kick a ball along the ground, it keeps moving at the same speed forever? Which one do you think? And the answer is A.

Yes, that's what we've been learning about, isn't it? And we've been saying that without friction forces, objects would keep moving at the same speed forever.

But because of friction forces, objects moving across a surface will eventually slow down and stop.

Well done, everyone.

Rough surfaces slow down moving objects, and then we've got a missing word here, than smooth surfaces.

Hmm, I wonder what that missing word might be to make that sentence make sense.

Have you got some ideas? And the answer is more.

Rough surfaces slow down moving objects more than smooth surfaces.

Did you come up with any other words or is that the word that you placed into the gap? Well done, everyone.

Moving on to our next practise task.

Aisha and Alex are discussing how a toy car rolls on a rough surface compared to on a smooth surface.

And Aisha says, "On the rough surface, the toy car will roll faster than on the smooth surface." But Alex disagrees and he says, "On the smooth surface, the toy car will roll faster than on the rough surface." So take a moment to think about this one.

Who do you agree with and why? Do you think the toy car will roll faster on the rough surface? Do you agree with Aisha? Or do you think the toy car will roll faster on the smooth surface? Do you agree with Alex? Pause the video and gather your thoughts.

And the answer here is that Alex is correct.

Did you get that one correct? On the smooth surface, the toy car will roll faster.

And the reason for that is because on the smoother surface the object will travel faster because a smooth surface creates less friction forces to slow moving objects down.

Well done, scientists.

Let's move on to our next practise question.

Now this time Sofia and Jun are discussing and they're saying that, well, Sofia is saying, "On the rough surface, the toy car will roll further than on the smooth surface." So not faster, they're thinking about the distance that the toy car will travel.

So do we agree with Sofia, that the car will travel the furthest on the rough surface? Or do we agree with Jun? And Jun is saying, "On the smooth surface, the toy car will roll further than on the rough surface." So again, take a moment to think about this one.

Who do you agree with and why? Okay, so this time it's Jun that's correct.

On the smooth surface, the toy car will roll further.

And that's because the smoother the surface, the further an object will travel.

Let's think about friction forces.

So this is because a smooth surface will create less friction forces, like the stone steps compared to the sandpaper.

And what happens here is that the objects are slowed down or they even stop from moving.

Fantastic work.

We're moving onto our final learning cycle now, and in this cycle we are learning about how scientists use their results to make conclusions.

Is everybody ready? We've been working really hard, haven't we? Onto the final part of the lesson now.

During an investigation, scientists record their results.

Some results are observations, things that the scientists have seen, and we've got a photograph here of a scientist working outdoors, recording their observations.

Some results are lists of data, and data is information, so things that the scientist has measured.

And an example of this is that scientists can record data in graphs, in charts, sometimes in tables.

There's lots of different ways that scientists can record the data that they have collected.

To complete the investigation, scientists need to decide what their results tell them.

So we need to make sense of the findings.

And don't forget, we need to answer the inquiry question that we started off the investigation with.

And this part of an investigation where we make sense of our findings and we answer our original question is called making a conclusion.

And that's one of our keywords in the lessons today.

Now, Jun did an investigation to answer the question, do different surfaces affect how far I can slide my pencil case? Oh, I like that question, Jun.

So this is Jun's inquiry question.

Have you ever done that at school or at home with a pencil case when you've slid it across a tabletop to see how far it slides? And Jun is wondering if different surfaces affect how far the pencil case will slide.

So this has got something to do with friction forces.

Here is Jun's table of results, and Jun tested his pencil case sliding over a wood surface, a carpet surface and a tiled surface.

And Jun measured the distance in centimetres that the pencil case slid across those different surfaces.

So we have on the wood surface, 63 centimetres, over the carpet surface, 37 centimetres, and over the tiled surface, 90 centimetres.

So let's start thinking about what those results might tell us.

What do you think Jun's results show? So we really need to be looking, don't we, at the distance.

A little bit like the toy cars rolling on different surfaces.

Is it the furthest they travel, the greater the friction force? Or is it the furthest they travel, the less the friction force? So we can see that the pencil case travels the furthest over the tiled surfaces, so would you say that's because there's more friction or less friction? This is what we need to do in the final part of an investigation where we start to make our conclusion.

Jun notices that on the smoother surfaces, his pencil case slid further.

Let's have a look at the greatest distance, 90 centimetres over the tiled surface.

Now would you say that tiles are smoother than a carpet? I definitely would, yeah.

Carpet's quite a rough surface, isn't it? A bit bumpy.

And would you say that tiles are smoother than a wood surface? Yeah, I think they are, aren't they? Because wood can be smooth, but I think in general tiles do tend to be a lot smoother than the surface of wood.

So that's a really good observation that Jun's noticed.

He's looking at the smoother surfaces are the ones where the pencil case slides that bit further.

So Jun's going to use that information in his conclusion.

"My investigation shows that the smoother the surface, the further my pencil case could slide." Yes, I agree with that.

And I think now Jun's thinking about friction forces and he's trying to explain his results even further.

"I think this is because smoother surfaces create less friction forces to slow things down." I'm really happy with that investigation, I'm very impressed, Jun.

I think Jun's really looked at the results that he's collected, he's tried to explain what they mean, and he's thinking about answering his inquiry question, fantastic.

Let's move on to check your understanding of this.

Lucy did an investigation to answer the question, which material makes the bounciest ball? Here are Lucy's results.

So Lucy's collected results in a table and we've got the material of the ball.

So Lucy has used a metal ball, a rubber ball, and a plastic ball.

And Lucy has measured the height that the ball has bounced, and we can see that our unit of measurement is centimetres.

So the metal ball has bounced 2 centimetres, and the rubber ball has bounced 10 centimetres, and the plastic ball has bounced 5 centimetres.

What conclusion would you make based on Lucy's results? Would you say A, the metal ball was the bounciest? Or B, the rubber ball was the bounciest? Or C, the plastic ball was the bounciest? And the answer is, did you get this one? Yes, the rubber ball was the bounciest, and we know that one because the rubber ball bounced to the greatest height.

It bounced to 10 centimetres compared to 2 centimetres and 5 centimetres for the other two balls, well done.

Let's take another check of our understanding of conclusions.

Which two of these items would you find in the conclusion? Is it a drawing of observations? Is it an explanation of what the results mean? Is it a list of measurements? Or is it an answer to the inquiry question? Now don't forget, it says which two of these items. So take a moment to think and choose just two from the list.

And the answers are in the conclusion we would find an explanation of what the results mean and also we would try to answer our original inquiry question.

Well done, everyone.

Moving on to our final practise task.

Does the type of surface a marble rolls on affect how far the marble moves? So here's our inquiry question from when we rolled the marble across different surfaces.

And remember, we were looking to see whether the type of surface affects how far the marble moved.

So our first part of the task is to look back at the data that you collected when you carried out this investigation, and that was part of Task A.

And I want you to look really carefully at that data and talk to a partner about what your data shows.

And we're really looking at, what does your data show about the distances that the marble travelled on the different surfaces? So just like we've been looking at different data that's being collected, we are looking at how far the marble travelled and what does that tell us about the type of surface.

So Izzy's giving us a hand here and she's saying that you could use this sentence to say, "Our results show that the marble travelled the least distance on.

." And then you've got to think about which surfaces.

And then also you might say, "Our results show that the marble travelled the furthest on.

." And then again, think about the surfaces.

Okay, so pause the video, look back to the results that you've collected, and start to gather your ideas about what does the data show.

Welcome back, everyone.

So by now you'll have had some time to look back at the data that you've collected.

You may have said something like Izzy, but don't forget that you may have tested different surfaces to Izzy.

So Izzy's saying, first of all, "Our results show that the marble travelled the least distance in the sand tray." Now did you try rolling your marble across sand and did it show the same results? Or did you have a different surface that your marble travelled the least distance? And Izzy's results also show that the marble travelled the furthest, so the greatest distance, on the tiles.

Now I'm wondering, did you test a tiled surface in your investigation? Or did you try rolling the marble over something else where the marble was able to travel really far? I wonder if you have anything different.

Now we've got a second part to our practise task.

We're still looking at the same inquiry question.

Does the type of surface a marble rolls on affect how far the marble moves? And we're really focusing on writing a conclusion now.

Remember, we want you to write a conclusion that says what your results show and also we want you to explain what does this tell you about the friction forces on different surfaces.

So you might want to use these sentence starters.

"Our results show that the marble travelled.

." Then you might want to say the most or the furthest or the least, and then remember to put in the first part of the task and tell me which surfaces.

But this is the tricky bit now that we're moving on to, I want you to explain, "I think this is because.

." And this is the bit where we we're really thinking about those friction forces.

"Our results show that the marble travelled.

." So then this might be the other one, the furthest distance.

And tell me which surfaces, yes.

And then the tricky bit is to say, "This shows that.

." And then again, you're bringing in your understanding of friction forces.

So pause the video and have a go at writing your conclusions.

I'll see you soon.

Let's have a look at some examples of this.

"Our results show that the marble travelled the shortest distance on the carpet.

I think this is because the friction forces slowed the marble down as it was moving along the surface of the carpet.

The carpet was the roughest surface, so it created the greatest friction force." Wow, that's a fantastic conclusion.

Was yours anything like that? Were you able to talk about friction forces? Were you able to talk about surfaces being rough? Now don't forget that your conclusion might look like this or you could have different ideas.

Let's take a look at another example.

And Izzy's saying, "I wrote my conclusion.

Is it similar or different to yours?" And here's Izzy's.

"My results show that the marble travelled the greatest distance on the tiled floor.

I think this was because there was not much friction force to slow the marble down.

The tiled floor was the smoothest surface, so it created the least friction force." Okay, so this time Izzy's concentrated her conclusion on the marble that rolled the greatest distance, and Izzy's thinking about how this was a smooth surface and she's thinking about surfaces that create the least friction force.

Fantastic work, Izzy, and fantastic work to all of you today too.

Let's finish today's lesson by looking back at all the learning from today.

So we know that objects move differently over different surfaces.

We also know that scientists can carry out comparative test investigations to compare different surfaces, and that's what you've been doing today.

You've been scientists, haven't you? Carrying out your comparative tests and you've been comparing different surfaces.

We know that friction forces are the forces that slow down moving objects, and eventually those objects will stop moving too.

And our results have showed us, well, I hope our results have showed us that it's a rough surface that will create a greater friction force against a moving object, and there's definitely a greater friction force than when an object is moving across a smooth surface.

Finally, we've learned about the conclusion part of an investigation, and we've learned that in a conclusion scientists explain what the results show or mean, and you've done a brilliant job writing your own conclusions to finish off the lesson today.

Fantastic work, scientists.

You have been amazing.

I'm really looking forward to working with you all again soon.

Bye, everyone.