Lesson video

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Hello, everybody, and welcome back to your final lesson on practical skills with me, Miss Roberts.

You might notice that my background looks a bit funny.

Can you see a shadow? That's because in today's lesson, we're going to be measuring the size of a shadow in order to write up an entire investigation.

So let's get started.

First of all, you're going to need a pencil and a pen, a ruler, and a notebook to write things down.

Later in the lesson, I'm going to show you an investigation that you can take part in if you've got the resources that I'll show you later.

If you don't that's okay, you can just watch mine and you can do it with me on the screen.

So we're going to look at our star words, we'll carry out the investigation, and think about what our investigation is going to involve, then we'll carry out the experiment, then we'll write about it, and then you'll do your final learning review of the unit.

So let's get started.

Our star words.

Star words, star words, star words.

Okay, the first word is results.

Your turn, results.

Your turn.

The next word is data.

The next word is data.

We said in the last lesson that data is information.

Data is information.

Well done.

The next word is units of measure.

Your turn.

Well done.

We've done this a few lessons in a row now.

Can you name me three units of measure? That's one.

That's another one.

Well done.

In my head, I hadn't grammes, kilogrammes, and litres are all types of units of measure.

The next word is increments, and what's I'm going to do my action is a small amount with my fingers, and then I'm building it up.


Your turn.

An increment is the steps that you go up in.

So for instance, on my ruler, it goes up in increments of a centimetre and we'll look at that later in the lesson.

The next word is conclusion.

Your turn.


Your turn.

Well done.

And variables.

Your turn.


Your turn.

Well done.

So team, this is the last lesson and today we're going to be writing up an investigation that we're going to carry out.

You really need to make sure that you've completed all of the other lessons in this unit so that you're really confident today 'cause you're going to be working quite independently.

So what is our investigation? Now, you might remember in the last lesson, we talked about the size of the shadow and when I've taught this before, I know that children get really excited to carry out this experiment.

So I thought, actually, why don't we have a go ourselves? We're going to have a go at testing for size of a shadow and how it changes when you change the distance of an object from a light source.

On the picture, you can see two children walking along and you can see that shadow is very long on the pavement.

Now, the shadow depends on the light source and it depends on how far that object is away from that light source.

That gives you a clue about what we might be about to talk about.

What do you think? Variable.

Yes, our favourite.

So our independent variable remember is the one thing that we change.

What's the one thing that we change? Our independent variable.

Well done.

Our dependent variable is the thing that we? Well done, that we observe or measure.

And then our control variables are everything we keep the same.

So we're going to be measuring the size of a shadow and how it changes when you change the distance of an object from a light source.

So I've got my light source and I've got my object.

Which one thing am I changing? Can you ever think? What's the one thing I'm going to be changing in this experiment? Can you tell your screen? Well done.

We're going to be changing the distance, the distance of the object from the light source.

So that's my independent variable.

What's the thing we're going to be observing or measuring? I've already given you a clue for this.

Well done.

It's the length or the size of the shadow, and you can see that's already why I've got a shadow in the background 'cause I'm going to be putting it on this wall.

Then the control variables are everything else we need to keep the same.

So I'm going to keep my light source the same.

I'm going to keep my object the same.

I'm going to use centimetres on my ruler.

That's going to stay the same.

I'm going to use the same bulb in my light source.

Not going to suddenly change it and everything else around me I'm going to keep the same.

So I'd like you to jot those down now on your notebook so that you remember what your variables are for this experiment.

Pause the video if you need more time.


So I've shown you already that my equipment is as follows.

I've got a small mug, I've got a ruler, and I've got a light source.

Now, before I get started, I need to tell you that this light source can get hot because it's using electricity and energy and that means that it can be very hot if I touch it or get too close.

You must make sure that you're being really careful and anytime you do an investigation at home, you need to make sure there's a grownup there to help you.

So please make sure that a grownup is there supervise you if you're having a go at home with me.

If you want to join with me and do the experiment, you can get the equipment now.

Pause the video and get your things.

If not, you can just watch me do it.

Okay, I've got my things so let's think about carrying out the experiment.

So what I'm going to do is I've got my light source here.

And with my object, you can see that it makes a shadow on the wall.

I'm going to move my mug towards the wall and you can see that the size of this shadow is changing when I bring it towards.


So what I'm going to do is I'm going to measure how far the object is away from the light source.

So, first of all, I'm going to start it 10 centimetres away.

Now, remember what did I say you need to be? Really, really careful.

So I'm not going to touch the light source at any time.

I'm going to hold it just enough away that my ruler can tell me 10 centimetres, okay? So then now I'm 10 centimetres away, you can see there's a shadow, or I just need to hold that mug a bit differently.

There you go.

And what I now need to do is I'm going to measure the size of that shadow.

So I'm going to hold the mug as if I'm drinking a cup of tea, but I'm not going to drink it.

I'm going to measure the height of my mug and I can see that it's 29 centimetres.

So I'm going to write that down on my table.

So 10 centimetres away and it's shadow is 29 centimetres.

I'll show you this in a moment.

Now, I'm going to go up in increments of five centimetres.

So if I was 10 centimetres before, now I'm going to be at 15 centimetres away.

So here's my mug, there's my shadow.

The size of my shadow is now 23 centimetres as the mug is 15 centimetres away from the light source.

So remember, I'm going up in increments of five centimetres each time.

I'm not going to change that either.

So now I'm going to be 20 centimetres away, going to hold my mug, I'm going to look at my shadow, and I'm going to measure the size of my shadow.

It's now 13 centimetres, and that was when it was 20 centimetres away.

So I'm just writing that down.

Now I'm going to be 25 centimetres, put my mug, look at my shadow.

Now it's 10 centimetres when I was 25 centimetres away.

And my last one is 30 centimetres away, put my mug, measure my shadow, now it's only eight centimetres.

So it's getting a bit smaller each time.

So I now have written down some very brief notes about my experiment.

I haven't written them in a table yet.

I'm going to move that so it's not glaring.

So what I now need to do is to present my results.

But first of all, I'm going to give you a chance to have a go at the experiment if you want to at home.

So if you want to, you can pause the video and carry out the experiment just like I did and then play the video again when you're finished.

Okay, I think I'm ready.

So now we need to write up the experiment.

What was the equipment that I used? What were the three things that I had? There were three pieces of equipment.

Do you remember when we looked at writing up a method, we use bullet points.

So what I'd like you to do is write out your equipment list using bullet points.

Pause the video and do that now.

Okay, after the equipment list came the method.

This isn't the method for this experiment.

This was the example I gave you when we did this lesson.

Let's see how many things you can remember using the method.

You need to underline it at the top of your page on the left-hand side.

We used adverbs of time to describe each sentence.

We had numbered steps to make it really clear so that somebody else could follow along or knew exactly what I did.

We also used the present tense.

So those are the key features of a method when you're writing up a scientific investigation.

I'd now like you to have a go at writing out your method for this investigation that I've just done or that you've had to go at.

Pause the video and have a go at your method now.

Do you think you've finished? If you have, you can carry on with the lesson.

If not, pause the video and keep writing.

Okay, so I'm going to show you my writeup.

I set the lamp up on a flat surface.

I placed the mug five centimetres away from the lamp and measured the length of the shadow.

Then I moved them up to the next increment, always moving it along a straight line from the lamp, then I moved the mug 10 centimetres away from the lamp and repeated the measurement.

I then repeated it in increments of five centimetres up until 30 centimetres.

Now, I've got a question for you, which I hope you've already spotted.

How could I improve the method that I've written up? What have I forgotten? There's one thing that I've forgotten to write in when I've been writing up my method.

Can you spot it? Look really closely.

I've used the present tense, I've done numbered steps, I've written method at the top, and they've written in clear sentences.

What's one thing I could have improved on? Can you tell your screen what's I've forgotten? Well done, you've spotted it, my adverbs of time.

If you need to add in your adverbs of time, please pause the video and add them in now.

Okay, so after our method, we need to present our results.

You can see on the screen that I've written up my table.

I showed you my notes that I made as I completed the experiment, but now I need to show them in a really clear way.

We learned how to draw a table of results earlier in this unit.

So if you need to recap, please return to that lesson.

If not, you can see my table on the screen.

So on the top left-hand column, you can see that I've written distance from light source and then my unit of measure centimetres is in brackets.

I've then written my results underneath my increments of five.

My right hand column, I've got the size of shadow, and again, my unit of measure centimetres in brackets, and then my results for how large the shadow was.

I want you to pause the video now and write up your table of results based on your experiment or you can copy my table out so that you've got a table of results in your notes.

Pause the video and have a go now.

Okay, so now that we've written our method, we've drawn upon results, we now need to write a conclusion.

What was the model that we learnt to structure the paragraph for conclusion? What was that model? Was it TEE model? Was it the BEA model? Was it the ABC model? Well done.

You've remembered.

It was the PEE model.

Make your point, give your evidence, and explain your evidence using your scientific knowledge.

My favourite bit.

So let's think about what our PEE using your results will be.

What's the point that you found from your experiment? What have you found? Can you tell your screen? You found that when the mug or the object, whatever you used, was closer to the light source then the shadow was bigger.

Can you give me a piece of evidence? You might need to use two pieces of evidence.

To support that point, I would use your smallest measurement and your largest measurement.

Now can you explain why that is? I know, but I want you to have a go.

Can you have a think.

Pause the video and think why is it that the shadow is bigger when the object is closer to the light source? Okay, I wonder what you thought about that.

It depends how much you already know about light.

I know that when an object is closer to the light source, then it is blocking more light.

So if I'm closer to the light source, let's bring it back in a second.

So if I'm closer to the light source, I'm blocking lots of light, but if I'm further away, I'm not blocking very much light.

So my shadow is much smaller because I know that shadows are lack of light.

That's quite a long way to say it.

I know that you're going to write it really concisely when you write up your conclusion.

So here are your sentence starters.

I'd now like you write out your conclusion for your experiment.

Pause the video, if you need more time.

I'm going to carry on.

So my conclusion was as follows.

Let's see if yours was close as well.

In our investigation, we found that as you move an object closer to the light source, the shadow gets bigger.

That was my point.

My evidence was as follows.

This was shown in our results as the size of the shadow was only nine centimetres at the longest distance and was 19 centimetres at the shortest distance.

This is because a shadow is made by blocking light and the closer an object is to the light source, the more light it blocks.

If you'd like to, you can use this to help you to finally write up your experiment and your conclusion.

Well done, everyone.

I am so impressed with everyone's science learning during this unit.

Lenny the Lion here wants to say a huge well done and he's going to give you an awesome cheer because you've learned so many things about writing up an experiment.

The important thing to know about this unit is that we have done lots of different experiments and used lots of different examples because whenever you do an investigation, whether it's about light, whether it's about sound or ecosystems or materials or whatever it might be, you can use all of the skills that you've just learned in your practical skills unit with me and apply that to all of your different scientific investigations.

I'm really proud of you all and you should give yourself a big pat on the back and well done for you this unit of learning.

Well done, everyone.