Lesson video

Hello, everyone, it's Miss Simkin, back again for your next science lesson.

I hope that you've all been keeping well and you're ready to do some awesome science this morning.

Let's get started.

Our lesson question today is what happens to particles during dissolving? So we're going to be looking at the science around what happens when things dissolve today.

For this lesson, you're going to need a piece of paper, a pencil, a coloured pencil if you want to mark your work in a different colour, and also a ruler.

There's also going to be a chance this lesson to do a practical yourself.

And so if you'd like to take part in that, then you'll need a glass of water, a spoon, and then some sugar and some salt.

If you don't have those things in your house, then that's okay, because you can just watch my demonstration and you can still take part in the lesson.

You might, however, if you want to take part, like to go and get those things ready now, in which case you can pause the video and you can go and get what you need.

Brilliant; we're also going to need these Star Words for this lesson.

So, we're going to need the word particle, dissolve, solute, solvent, and solution.

We're going to practise saying those words now.

You can see I need to practise as well, 'cause I tripped up on one of them.

So, I'm going to say the word, and then you're getting to say the word.

Particle; dissolve; solute; solvent; and solution.

Brilliant; most of those words we're going to learn during our lesson, but we've been talking about particles in our previous lessons.

And a particle is essentially anything that has mass.

So, everything is made up of particles.

It's like the smallest piece that everything is made up of.

This is the structure we're going to follow in our lesson today.

We're going to start with some quick recap.

Then we're going to do a sugar investigation.

Then we're going to look at what a solution is.

Then we're going to do a salt investigation, and then we're going to do a sand investigation.

So, let's start with our recap.

You have a particle diagram for the three states of matter.

Can you point to your screen and say which one is a solid, which one is a gas, and which one is a liquid? Great.

Let's check if you got that correct.

So, our first one is our solid.

Then we have our liquid.

And then we have our gas.

We've also got some actions that go with these to help us remember.

So, let's practise our actions now.

Our action for a solid is this, 'cause our particles are close together and they're vibrating.

Can you show me the action for a solid now? Great.

Our action for a liquid is this.

The particles are still touching each other, but they have space to slide around each other, slide past each other.

Show me your action for a liquid.

And this was our action for a gas.

The particles aren't touching.

They're far apart from each other.

And they're moving very quickly.

Show me your action for a gas.

Great.

We've also looked at, oh, actually, I was going to tell you something now that's going to give you a bit of a clue.

I'm going to show you the question before I say that.

So, I've got two particle diagrams here, A and B.

What are the differences between the two diagrams? Pause the video and have a think for me.

Great; so, one of the differences you might have spotted is that diagram A is a picture of liquid particles, you can see from how they're arranged.

And diagram B is a diagram of gas particles, and you can see that from how they're arranged.

They're further apart.

But there's something else that's different about these two particle diagrams. Particle diagram A has two orange particles in it.

We learned this last lesson.

What do we call a mixture or a substance that has more than one type of particle? I'm giving you a clue with my actions, and I actually gave you a clue with my word.

We call it a mixture, or an impure substance.

So A is an impure substance 'cause it has more than one type of particle in it.

And B is a pure substance 'cause it only has one type of particle in it.

It's only got the green ones in it.

Okay, so pure means one type of particle.

Show me the action.

And impure is a mixture.

It's got more than one type.

That's why we're mixing it action, the action for impure.

Brilliant, well done if you spotted those differences.

So now, we're going to do a bit of an investigation into sugar.

Before we start, can you please draw this table on your piece of paper? So you can see you've got a row at the top that says Substance, Sugar, Water, Mixture.

And then you've got a row that says Observation, and then we've got three blank boxes where they're going to write our observations.

Can you pause the video please and draw this table for me now? These are the steps that we are going to follow with our investigation.

So I'm going to read through them.

And then if you have the equipment, you can have a go at doing them.

If not, I'll then follow them through when I do my demonstration.

So number one, take a spoonful of sugar and put it into your water.

Stir the water with your spoon.

I then want you to have a look at the mixture and write down what you see.

Now, I'm going to take a spoonful of my sugar and I'm going to add it to my glass, and then I'm going to stir it around.

And I'm going to keep stirring.

You can see, already, that there is not very much of my sugar left in the glass.

Lots of it has dissolved already.

There's still some left at the bottom though.

I'm going to keep stirring until it is all gone.

And now I can write down my observations for my new mixture.

So I'm just going to show you under the visualizer.

So you can see, you should be able to see, that there is no sugar left.

So write down your observations for your mixture.

Should have written down pretty much the same thing as you wrote down for our water.

It's a clear, colourless liquid.

Now we're going to learn some of the key vocabulary to help us explain what was going on in that investigation.

So, you can see from these pictures that we started with our sugar and our water, and we combined them into a mixture of sugar and water that was also clear and colourless.

But we have some key vocabulary to describe these parts.

So when a solid, like sugar, dissolves in water, it forms a solution.

So that mixture we had at the end, we call that a solution.

What do we call the mixture we had at the end? A solution.

A solution is a mixture of a solid, which we call a solute, and a liquid, which we call a solvent.

So in this case, our sugar, our solid, was the solute.

What's the solid? A solute.

And the liquid, our water, was the solvent.

What was the liquid? Great, okay.

So, it can be hard to learn three new pieces of vocabulary at once, so I've got some sticky ways to help us remember this.

The first one is this.

When we're dissolving and we're making a mixture, we have to add our solute and our solvent together.

So that's our sugar and our water, in this example, together.

And that gives us our solution.

We can remember that the solution is what we end up with, because solution is another word for answer.

So you might have used that in your math lessons before.

What's the solution to this problem? So, solute and solvent equals solution, because solution is the answer.

I've got another way of remembering.

Solvent has a V in it.

And we can remember that that's the liquid because vases also has a V in it.

And vases hold liquids.

So, if we go back to our first picture, we know that our solution is the mixture we end up with when our solid has dissolved, because the solution is the answer.

Our solute is the solid we're adding, and we can remember which is which, that the solvent is the liquid because of the V for vase, and vases hold liquid, okay? So when we mix a solid and a liquid together, if that solid dissolves in our liquid, then we get a solution.

This is what the particles look like.

Okay? So again, here we have our solid that we started with, which we call a solute.

And it was sugar in this example.

If we zoom in, this is what our sugar particles would look like.

So they're in a regular arrangement and they're very close together, just like we would expect our solid particles to be.

This is what our solvent, our liquid, would look like before we mix it together.

This is what our water particles would look like.

They're still touching, mostly, but they're a bit further apart.

They're in a random arrangement.

When the solute is added to the solvent, we get a solution and this is what we would expect the particles in the solution to look like.

So, when the solid is added to the liquid, the solid particles are pulled apart.

So those green, solid sugar particles we saw are pulled apart and they're surrounded by the liquid particles.

So you can see these blue ones are my liquid particles.

And that's why you can no longer see the solid.

Because it's dissolved.

It's been split into lots of very small pieces.

And that's why our solution is clear and colourless as well, because those solid particles have been split and separated by the liquid particles into lots of very small pieces.

Okay.

I have some questions for you now.

There was a lot of new information there.

So, have a read of these questions, and I'll read them to you in a moment.

If you think, yeah, I'm ready to answer these questions, then have a go.

If you're thinking, I need to go back and watch that part of the video again, and maybe make some notes, then that's okay as well.

Okay, go back about two minutes in the video and watch the part, and make some notes about the solute, the solvent, and the solution.

Here are your questions to answer.

What was the solute in the experiment? What was the solvent in the experiment? And then, can you explain why the sugar water produced at the end of your experiment, so that mixture at the end, that solution, was no longer pure? Pause the video and have a go at answering those questions for me now, please.

Great.

Let's check your answers.

So, our first question, the answer is sugar, our solute was sugar.

Our second question, the solvent, remember, it's got the V for vase, so that's the liquid, is water.

And number three, you might've written it an answer like this, "A pure substance contains only one type of particle.

The solution", or the sugar water, "at the end contained water and sugar particles." You might also have written, it contained a mix of particles or it contained more than one type.

Well done if you got those questions correct.

If you made a mistake, that's okay.

Just correct your answers.

We're going to do this again and again in the lesson until we're really, really confident on this new vocabulary that we're learning.

So, the next thing we're going to look at is salt.

So, we're going to repeat the experiment that we've just done, except this time we are going to use salt.

Before we begin, I'd like you to make a prediction.

So think about what happened with our sugar investigation, and can you make a prediction? So that means you're going to try and make an educated guess about what's going to happen.

So, what do you think is going to happen to the salt when we add it to our water and mix it? So you might want to start your sentence with, I predict that, and then I want you to explain, why do you think that will happen? I predict that the salt will not dissolve because, or, I predict the salt will dissolve because.

See if you can use the word particles in your answer.

Pause the video and write your prediction for me now, please.

Great.

Let's see if your prediction was correct.

Let's have a go at trying this with salt.

Let's try a demonstration with salt now.

So again, I've got my glass of water.

I've got my little dish of salt, and I'm going to put one spoon of salt into my water.

You can see as soon as I drop it in, you can see the solid at the bottom.

Now, I'm going to stir it.

Let's see if your prediction is correct.

View what happens to our salt.

I can see the salt is starting to dissolve.

I've still got a few solid salt pieces at the bottom.

I'll keep mixing.

Now that I've mixed, there is no salt that I can see in my water.

I know that there is salt in this water, because if I drink some of it? Ugh, it is really, really salty.

Ugh.

But I can't see any of the salt because the salt has dissolved in the water.

So those solid salt particles have been pulled apart and surrounded by water particles.

And so they're now in such small pieces that I can't see them, but I can taste them, ugh.

Now, this on the board is a diagram of the demo that we've just done.

So you can see A is showing our little dish of salt.

B is showing our beaker or our cup of water.

And then C is our mixture, our solution, that we had at the end, where we have our salty water.

Can you draw what the particles would look like for each of these? So you don't have to draw, you don't have to draw the beaker and the salt and the cups.

You can just draw the particles for A, for B, and for C.

So think about, are they going to be solid, liquids, or gases? How are they going to be arranged? You need to use a different colour for your water and for your salt.

And then think really carefully about what do the particles look like in C when we have a solution? I'd like you to pause the video and have a go now.

If you're getting really stuck, then you could always go back to the video.

Have a look at our sugar particle diagrams and see if that can help you.

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

Brilliant.

Let's see if you've got something similar to me.

So, these were my particle diagrams. In A, we had our salt particles.

So they're one colour.

I chose green.

It doesn't matter if you chose a different colour.

But the important thing is that they are all arranged in straight rows and they're touching each other, because that's what solid particles look like.

Then in B, we had liquid particles.

So these should now be a different colour to your solid particles.

It doesn't matter what colour you chose, and some of them should be touching, but they're in a random arrangement, okay? More higgledy-piggledy.

That's what I like to say.

And in C, this is when you have both of the particles.

So most of them are liquid ones, but then you have one or maybe two solid particles surrounded by those liquids molecules.

Well done if you got that correct.

If you made a mistake, that's okay.

Just pause the video and correct your answers using what's on the screen for me now, please.

Great.

I've got some questions for you.

So, thinking about our salt and water demonstration, can you answer these questions? What was the solute in this experiment? And what was the solvent in this experiment? Remember our special way of remembering which one's the solid and which one's the liquid.

Think about which one has a V for vase in it.

Pause the video and answer these questions for me now, please.

Fantastic.

Let's check our answers.

So our solute this time was salt.

That's our solid.

And our solvent, which had V for vase in it, must have been our liquid.

And that was our water.

Give yourself a tick if you got those correct.

Okay.

Here are your next questions.

Number three, explain why the substance produced at the end of your experiment was no longer pure.

So why was that salty water no longer pure? And number four, explain what happened to the particles of salt and water during dissolving.

So think about that diagram that you drew for C.

Can you explain in words what's happened in that particle diagram? Pause the video and complete those questions for me now, please.

Good job.

Let's check our answers.

So, for number three, you might have written something like this.

"A pure substance contains only one type of particle." And, "The solution at the end contained both water and salt particles." Okay.

So well done if you had written something like that.

You might also have written that the solution at the end is a mixture, or it contains more than one type of particle.

Those would be correct answers as well.

For number four, we're asking what happened to the particles in our solution at the end? So, what happened was, when the solid particles, so the solid salt particles are added to the water, the solid, or the salt particles, are pulled apart and surrounded by the liquid particles.

So, you might not have written the exact same sentence as me, but the key points here are that the solid particles are pulled apart and surrounded by the liquid particles.

Or you might have said the salt particles are pulled apart and surrounded by the liquid particles.

Okay? So those are your key words.

If you've included pulled apart and surrounded, that's great.

Can you underline them? If you wrote a really good answer, but you didn't say the words pulled apart or surrounded, could you pause the video and rewrite your answer with those two key words, please: pulled apart and surrounded.

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

Great.

Let's have a look now at our sand investigation.

So, I am going to show you now a demonstration with sand.

So I'm not asking you to take part this time, because I am assuming that you're not going to have sand at home, whereas you might've had sugar and salt in your cupboards, okay? If you do, for some reason, have sand at home, or maybe next time you come across some place with sand, like if you go to the beach or a park with a sand pit, then you can give it a go.

But for now, I just want you to watch me.

I want you to see what happens this time when I put my solid in my liquid, when I put my sand in my water.

Now we're going to investigate what happens when we add a new solid, sand, to water.

Okay? So I've got some sand here.

You can see it's quite dark coloured sand, and I'm going to add a spoon, just like I did with my salt and my sugar, to my water.

And we're going to see what happens.

Okay? So it's dropped to the bottom, just like my salt and my sugar did.

And I'm going to mix it.

With my salt and my sugar, I had to mix for about 30 seconds until I got them to dissolve.

So, let's try and mix this sand for about 30 seconds.

You can count out loud with me now.

One, two, three, four, five, six, seven, eight, nine, ten, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, and 30.

What is different to our experiment with sand than when we did it with sugar and salt? Have a look.

What can you see at the bottom? The sand is still there.

I mean, it's made my water a little bit cloudy, but that might be some of the other stuff that is in with my sand, 'cause it's from my garden.

But you can see that the sand, the solid sand particles, are still there at the bottom of my cup.

They haven't dissolved.

So we saw that time, that my sand did not dissolve in my solvent.

This means that sand is insoluble.

If it cannot dissolve, then it's insoluble.

If it can dissolve, like sugar and salt, we call it soluble.

So what do we call it if it can dissolve? Soluble.

One more time.

What do we call it if it can dissolve? Soluble.

And if it can't dissolve, what do we call it? We call it in soluble.

Okay.

I'm going to give you a quick quiz now.

Sugar.

Is it soluble or insoluble? Either write it down or say it to your screen.

Great.

Sugar is soluble because it can dissolve.

We saw that ourselves in our demonstrations earlier.

Sand.

Soluble or insoluble? Say it to your screen or write it down.

Sand is in soluble.

We saw that in our demonstration just now.

It does not dissolve.

And lastly, salt.

Is it soluble or insoluble? Say it to your screen or write it down.

Salt is soluble.

It does dissolve.

That brings us to the end of our lesson.

Well done for all of your hard work today.

I know that we learned a lot of new vocabulary.

So let's just have a little look at our Star Words before we finish the lesson, and you go and do your post-lesson quiz.

So, we were looking at particles today, which is essentially anything that has mass.

We were looking at what happened to the particles when they dissolved.

When particles dissolve, it's because the solid particles get pulled apart and surrounded by liquid particles.

So that's what's happening when dissolving is going on.

We learned about two types of solid: soluble solids, ones that do dissolve, like salt and sugar; and insoluble solids, ones that don't dissolve, like sand.

And then we learnt the words solute, solvent, and solution, which are our three parts of what's going on when we're dissolving something.

So, we start with our solute and our solvent.

So our solute is the solid, and the solvent is the liquid.

And we can remember.

How can we remember that solvent was the liquid? Tell your screen.

Because it's got a V for vase, and vases hold liquid, okay? And then, when we mix a solute and solvent together, we get a solution.

And we can remember that the solution is what we end up with because a solution is another word for an answer.

So when we do solute, add solvent, it equals solution.

Great job today.

If you would like to send me a picture of you doing your practical, or if you'd like to share your work, then you can ask your parents or your carers to share a photo or post your work on Twitter, using the hashtag #LearnWithOak, and tagging Oak National if you'd like.