Lesson video

It is Miss Simkin back for your next science lesson.

I hope that you have had a really lovely week and been getting up to lots of fun stuff.

I've been doing lots of reading this week.

And I actually learned a new fact, which I'm going to share with you just before we begin because you know I love an animal fact.

I discovered this week that polar bears, big white, fluffy, polar bears actually have skin that is pitch black, which is really cool.

I've obviously never seen a polar bear's skin before.

And that just really surprised me when I read that.

So there's our facts before we begin and now let's start our lesson.

Our lesson question today is, what do particles in pure substances and mixtures look like? So last lesson we looked at the particles in solids, liquids, and gases.

So we're going to recap that before we start because now we're going to look at particles in mixtures and pure substances, and we'll learn exactly what those mean this lesson.

For our lesson today, we are going to need a piece of paper, a pencil, a colouring pencil if you would like to mark your work in a different colour, and a ruler so that when we draw a table later in the lesson we can be really neat.

We're also going to need these star words.

So we're going to practise saying our star words.

So I'm going to say them, and then you're going to say them.

Okay, it's important we practise saying our star words so that when you are telling your family, or your friends, or your normal teachers about your science that you've learned, you say all the words correctly, and it also helps us to remember them.

Okay, so pure.

Impure.

Substance.

Particle.

Mixture.

Great, so we're going to be learning what those words mean this lesson.

But we will define particle before we move on because we learnt about particles last lesson.

So the particle is essentially something that has mass, that weighs something.

So everything is made out of particles and these particles have mass.

We can think of them as the smallest piece that everything is made out of.

So this lesson, we are going to start with some quick recap, see what we can remember from last lesson.

And if you don't know what I'm talking about, and you're thinking, "What do you mean lesson Miss Simkin? This is the first video I've watched." That means that you need to go back on the Oak National website please, and watch our first lesson of this unit on physical and chemical changes so that you can catch up with what you've missed.

We are then going to learn specifically about water and water particles, and then we're going to learn about gold and gold particles.

So first of all, I'll recap.

You have three particle diagrams here.

One is a solid, one is a liquid, one is a gas.

Can you remember which is which? Point to your screen and say which is which or you can write them down if you'd prefer.

Great, let's see if you were correct.

Our first one is our solid.

In solids, like my phone, definitely solid, our particles are really close together, in fact they're touching, and they're in regular patterns.

So you can see they're arranged in straight rows and columns.

Our next one was a liquid.

And we did an action for this last week, okay.

This was our liquid action, show me if you remember.

And that's because our liquid particles are still quite close to each other, they're still mostly touching, but they're able to slide freely over each other.

And then finally, that must be our last state is gas.

And you can see our gas particles are far apart from each other and then moving really quickly.

Okay, so actually just before we move on, can everybody show me that action? So just to remind you solid, , that sound is the vibrating.

Liquid, and gas, you can get crazy with gas.

Okay, now I'm going to say it and you're going to do the action.

Solid, liquid, gas, liquid.

Did I catch you up? Good job.

Okay, we also looked at what happens when these states of matter, solids, liquids, and gases change, okay.

So we can go from a solid to a liquid, for example, that's what A is showing on the diagram.

We're going from a solid to a liquid, ice to water.

What's it called when that happens? Can you label the diagram with these changes of state? You don't need to draw it.

You can just write A equals and then what the name is, I nearly told you.

Pause the video and write it down for me now, please.

Great, let's check what you can remember.

If you got any of roles, you don't need to worry about it.

Every time you make a mistake, our brain gets a bit stronger.

So actually making mistakes really helps us with our learning.

If we never made mistakes, then we wouldn't learn as much.

There we go.

So A was melting.

B was evaporating.

If you've written boiling, you can give yourself a tick as well.

D is condensing, so that's where gas goes to a liquid.

Like what happens when we have a hot, steamy shower and we get those water droplets that on our mirror.

And C is freezing.

Good job, if you've got those correct.

Okay, let's move on to our learning about water molecules.

So here we have a glass of water and we've zoomed in.

That's what that showing you to show us what the particles in this glass of water would look like.

This is an example of pure water.

Because pure substances contain only one type of particle.

How many types of particles do pure substances contain? Show me, one, okay.

And you can see from the picture that there is just one.

They're all green, they're all the same colour, they're all the same size.

So this pure water only contains water particles.

What about this glass of water? What is the difference? What can you notice is different about the water particles in this glass of water? Right, there's not just one type anymore.

I can see my green water particles, but there's also two orange particles and a blue particle.

The water that we drink from our taps is water like this.

It's not pure.

It contains other dissolved substances like calcium and magnesium ions.

So those orange and blue particles, they're calcium and magnesium ions.

Now impure water from our tap is obviously safe for us to drink, okay.

But it's not pure.

So particles and a mixture that make our sample impure are called impurities.

So these little particles are impurities are calcium and magnesium ions.

Say it with me, what are they called? Impurities, okay.

So when something has only one type of particle, we call it pure.

But when it's got a mix of particles, it's got more than one type, we call it impure.

Okay, I'm going to show you a series of particle diagrams now.

So you can see A is already on the screen.

And I want you to decide whether A is showing particles of the four options on the top.

So is it an impure liquid or an impure gas? Sorry, is it a pure liquid or a pure gas, or an impure liquid or an impure gas? So you're going to have to think about two things.

First of all, you need to think, is it a liquid or a gas? So you're going to see how are the particles arranged? And then you need to think, is it pure or is it impure? So pure means one type of particle, impure means more than one.

So pause the video and decide and write down please, what is A? You could even draw the picture if you wanted to.

Pause the video and complete the task now.

Great, so before I show you the next, I'm going to tell you what the correct answer for A is just so that we can check.

Now I can see that the particles in A are quite close together, but they're not in a regular arrangement, so they must be a liquid.

Okay, so I'm going to write down liquid, but now use to decide whether it's pure impure.

Well, I can see that there are two types of particles.

There's green ones and there's orange ones.

So it must be an impure liquid.

Well done, if you've got that correct.

Have a go now at B for me, please.

What is B? Write it down using the four options at the top, please.

What is C? And finally, what is D? Pause the video if you need some more time to complete this section.

Brilliant, let's check your answers.

So we already went through A.

A is an impure liquid, give yourself a tick if you got that correct.

B is a pure gas.

You can see it's a gas, the particles are further apart and it's pure because there's only one type of particle.

How many types of particle? One, great.

Pure liquid, was C.

And D was impure gas, well done if you got those correct.

Okay, I've got some questions for you now.

What is meant by a pure substance? Give you a hint.

Question two, impure substances are also called mixtures.

Why do you think this is? And why is tap water not pure water? Remember, if you ever see questions in a science lesson and you can't remember the answer, the beauty of learning from a video is that you can scroll back and you can listen to me say it all over again.

So pause the video, scroll back if you need to and complete the answers to these questions now, please.

Fantastic, let's go through the answers.

So number one, what is meant by a pure substance? A pure substance contains only one type of particle.

Number two, impure substances are sometimes called mixtures because they contain a mix of different particles.

And number three, it contains dissolved substances such as calcium and magnesium ions.

Or you might've said it contains impurities.

Well done if you've got those correct, you can give yourself a tick.

If you made a mistake, that's okay.

Just pause the video and correct your answers in your different colour now, please.

Going to look at gold now.

So this is a picture of pure gold and it's called 24 karat gold.

Because it's pure, we know that it only contains gold particles and it has a yellow gold colour that we're all very familiar with.

Sometimes different types of gold are used to make jewellery.

And one thing that can be different between these types of gold is the colour.

So this change of colour is due to the presence of impurities.

So pure gold has only gold particles.

And it's this kind of, I want to say gold in colour, but it's this kind of yellowy colour.

But you also get different kinds of gold.

So this is rose gold, and rose gold contains copper impurities.

So copper is another type of metal.

And rose gold has copper particles and gold particles.

And that's why it has this characteristic, pinkish colour, that's why they call it rose gold.

So you can see the impurities changed the colour of the gold.

They give it different physical properties.

Another type of gold is white gold, and white gold contains platinum impurities.

So again, platinum is another type of metal and white gold contains platinum impurities.

And this gives it a silver tone.

These are the most common colours that it's possible to make from gold, the most popular.

But it's actually possible to make other colours, including greens, you can even get green gold.

And this is an example that shows that impurities aren't always a bad thing.

Sometimes adding impurities can change the properties in a way that's good for a metal.

Okay, I've got some questions for you to answer, please.

Why is 24 karat gold pure? Which impurity poses a pink gold colour in gold? And which impurity causes a silver colour in gold? Pause the video and complete these questions for me now, please.

Great, good job.

Let's go through the answers.

So the answers are, it's pure because it only contains gold particles.

Copper impurities make rose gold pink.

And platinum impurities make white gold silver.

Well done if you got those correct.

Okay, the next thing I would like you to do please is I want you to draw and complete this table.

Before you do it, let's just talk through what we've got already.

So you can see there's three columns with the three different types of gold.

So we've got 24 karat yellow gold.

We've got 18 karat rose gold, and we've got 18 karat white gold.

So that karat refers to the amount of gold particles there.

So that's why in 24 karat gold when you've only got gold particles, you've got that really high karat, a higher number.

Whereas with 18, well both the white and the rose gold are 18.

And that's because they have fewer gold particles because the other particles are impurities.

Okay, so I would like you to draw this table.

If you have three colours, then you can draw your gold rings and your three different colours of gold.

If you don't have any colours to hand, it's okay to just skip those drawings out, as long as you have the heading of 24 karat gold, 18 karat rose gold, and 18 karat white gold.

Okay, so before I explain the task, could you just get your table ready so it looks like mine.

Pause the video and do that for me now, please.

Great, okay.

Now that empty box is where you are going to draw a particle diagram for each of these types of gold please.

So we've been looking at particle diagrams through the lesson.

You're going to draw small circles to represent your particles.

The first thing you need to think about is, is our gold a solid, a liquid, or a gas? Time screen, it's a solid.

So we're going to have to draw solid particles.

Think, what do our solid particles look like? Then you need to look at that percentage row.

So in our pure 100% gold, all of your particles are going to be gold.

They're going to be the same colour.

But that's not the case for the rose gold and the white gold, because they've got impurities.

And it gives you the percentages there.

So if you think you can work out the percentage, the number of particles by yourself and you fancy little mass challenge today, then pause the video and you can start your particle diagrams now.

If you would like a little hint on the mass, then that's okay, I'm going to give you a little hint.

My suggestion would be to draw 16 particles in each of your diagrams, okay? So in your gold, you're going to draw 16 gold particles.

Then when you get to rose gold and white gold, 75% of them are going to be gold.

75% is the same as three quarters.

So if we divide 16 by 4 to find one quarter, that would be four.

So 25% is one quarter.

So you're going to draw four particles as your copper or your platinum impurities, and then 12 particles as your gold particles.

Okay, that's your mass hint.

Pause the video and complete this task for me now, please.

Great.

Did your work look something like this? So I've chosen to draw 16 particles.

You might have a different number than me, but this is what it's going to look like.

In the first one, they should all be the same colour.

They should be arranged in straight rows and columns and touching each other.

In the second one for our rose gold, and we have the same arrangement, but you have some copper impurities mixed in there.

And the same with our white gold, except that platinum impurities, okay? Now your impurities and your particles should be a different colour, and you might even have added some labels to show what they were.

Pause the video if you need a chance to correct your work now.

Great, you guys have worked so hard today, good job.

Just before you go and take your end of lesson quiz, let's have a look at our star words.

So these are the words that we've learned this lesson.

We've been looking at particles, which are anything that has a mass.

We've been looking at particles in different substances.

And we've been looking at pure and impure substances.

Can you show me the action for a pure substance? Great, because it has only one type of particle.

And now can you show me the action for an impure substance? Exactly, because it has a mix of different particles.

So another word for an impure substance is a mixture.

If you would like to share your work that you have completed today, then I would love to see it.

And you can ask your parent or your carer to share a photo of your work on Twitter.

If they do then please make sure they include the hashtag #LearnWithOak and then I'll be able to find it.

And you could also include #ONAscience.

You've worked so hard today that Charlie has appeared.

Charlie, say hello.

What's that there? Good boy, watch this, touch.

Oh he's a clever boy, have a nice day everybody.