Lesson video

Hello, my name is Dr.

Shorack and I'm really looking forward to learning with you today.

We are gonna have a lot of fun as we move through the learning together and deepen our understanding of this topic.

Welcome to today's lesson.

This lesson is from our unit Measures, Mass and Capacity.

The lesson is called Comparing and Estimating Mass and Volume.

We are going to deepen our understanding of how we can compare objects with ones we know to work out or to estimate their mass and volume.

Sometimes new learning can be a little bit challenging, but I know if we work really hard, we will be successful and I am here to guide you through that learning.

So shall we find out? How do we compare objects with ones we know to estimate mass and volume? These are the key words that we will be using in our lesson today.

Estimate, mass and volume.

You may have heard those words before, but shall we practise them anyway? My turn, estimate.

Your turn.

Nice.

My turn, mass.

Your turn.

Lovely and my turn, volume.

Your turn.

Brilliant.

An estimate is a given value number or quantity that is near to the true amount.

It's a number close enough to the right answer.

It's roughly the right answer.

Mass is a measure of how much matter something contains.

We commonly measure it by how much something weighs and that can be measured in grammes or kilogrammes.

And volume is the amount of space that an object takes up.

In this lesson, we mean the amount of liquid in a container and volume can be measured in millilitres or litres.

And you can see my diagram here where I'm showing you that the volume of orange juice in the jug is 100 millilitres.

So today we are looking at comparing and estimating mass and volume.

We'll start by looking at how we can compare mass and volume.

These are the characters who are going to help us in our learning today.

Aisha, Sophia, Jacob and Andeep.

So Aisha has a tennis ball.

Can you visualise that, what a tennis ball looks like? That's right, like that.

Sophia has a cricket ball.

"Our balls appear to be the same size." "Then they will have the same mass," Sophia is saying.

Ooh, Aisha is disagreeing.

I wonder why Aisha is disagreeing.

The balls are the same size, so surely they have the same mass.

What do you think? To see who is correct, Aisha and Sophia measure the mass of their balls using scales.

There's the tennis ball.

The mass of my ball is 50 grammes.

Can you see that? That's where the arrow is pointing isn't it? To the 50.

Then they measure the mass of Sophie's ball, the cricket ball.

What do you notice? That's right, the mass of the ball is 150 gramme.

Even though the balls are the same size, they had different masses.

The tennis ball was 50 grammes, which is smaller than the mass of the cricket ball, which was 150 grammes.

So what can we learn from that? Yes.

The size of something does not determine how much mass or matter it has.

A tennis ball and a cricket ball are about the same size.

Maybe you have something you could try holding.

However, a cricket ball is solid while a tennis ball is hollow, that means it's got nothing inside it.

So the cricket ball has more matter inside it and because of that it has a greater mass.

True or false, two objects are to the same size, will have the same mass.

Do you think that's true or do you think that's false? And why? If objects are the same size, they must have the same mass.

Or is it because objects of the same size may have a different amount of matter inside them so may have a different mass? Maybe find someone and have a discussion with them about this statement.

Two objects that are the same size will have the same mass.

Press pause.

And when you've had a discussion and you think you know, press play.

How did you get on? Did you say that's false? We know that from the tennis ball and the cricket ball, don't we? Because objects are the are the same size, may have different amounts of matter inside them so they may have a different mass.

Let's have a look at this then.

So Jacob has a box, that's Jacob and his box.

Andeep has a larger box.

Andeep is saying that his box is larger so its mass will be greater.

Hmm.

Jacob is saying not necessarily.

What do you think? Will the larger box have a greater mass? To find out if the larger box has the greater mass? Jacob and Andeep measure the mass of their boxes using scales.

What do you notice about the mass of Jacob's box? That's right.

It's in between 400 and 600 isn't it? That's right Jacob, the mass of the box is about 500 grammes.

Let's look at Andeep's box that is now on the scales.

What do you notice about it's mass? Remember this is the larger box.

Do you notice the arrow is pointing between the 200 and 400? That means, as Andeep is telling us, the mass of his box is about 300 grammes.

Hmm.

So the smaller box has the largest mass.

Did you guess that? It's 500 grammes, the smaller box and that is greater than 300 grammes.

Hmm, but how is that possible? Jacob's box is smaller.

Ah, thank you Andeep.

The smaller box contains paper.

Larger box is empty.

The size of something does not necessarily determine how much mass or matter an object has.

The small box contains paper.

The large box was empty.

The small box has got more matter inside of it.

And because of this it has a greater mass.

Larger objects are not always heavier.

It really is all about what is inside them, what matter they are made up from.

Let's check your understanding.

True or false, larger objects always have a greater mass.

So have a think about that.

Is that true or is that false? And why? Is it because larger objects are bigger in size and so must have a greater mass? Or is it smaller objects may have more matter inside them so they may have a greater mass.

Pause the video and when you think you know press play.

How did you get on? Did you decide that that's false? Larger objects do not always have a greater mass.

We saw that with the boxes, didn't we? It all depends on what is inside of them.

So smaller objects may have more matter inside them so they may have a greater mass.

So that's really key learning here.

Just because something is bigger does not mean it has a greater mass.

It's all about what is inside of them.

And sometimes we can't tell that just by looking.

Let's move on and look at volume.

Jacob has a glass with some liquid in.

Andeep has a different glass with some liquid in.

Both glasses are full to their capacity so that means they can't put any more liquid in their glasses or it would spill over.

Jacob is saying that he has more liquid because his glass is taller.

Ooh, Andeep is disagreeing saying not necessarily.

What do you think? Who is correct? Will there be more liquid in the taller container? To see who is correct Andeep and Jacob measure the volume of water in their containers using the same measuring jug.

This is Jacob's container and the liquid that's in it.

The volume of liquid in my glass is about 150 millilitres.

We can see that because there are five equal parts in between the 100 millilitre marks.

So each part is worth 20.

The level of his liquid comes up to after the second part, which would be 40.

And then halfway, so that's another 10.

So that will be 150 millilitres.

They then pour the liquid in Andeep's glass into the measuring container.

What can you tell here? It's the same container, so there are still the same number of equal parts between the marked intervals.

So each part is still 20 millilitres and this liquid reaches the end of the fourth part.

So the volume of liquid in the glass is about 180 millilitres.

So even though the taller glass looks like it should hold more liquid, it didn't did it? 'Cause 150 millilitres is less than 180 millilitres.

So Jacob's glass, although it looked taller, had the smaller volume of liquid.

So what have we learned? That's right.

The capacity of taller containers is not always greater.

Taller containers may be narrower and so may not hold as much liquid as shorter, wider containers.

Let's check your understanding.

Is this statement true or false? Taller containers always hold a greater volume of liquid.

Have a think.

Is that true or false? And then why? Is it because taller containers are bigger and so they must be able to hold a greater volume? Or is it smaller containers may be wider and so they may be able to hold a greater volume? Pause the video.

Have a think about it and when you think you know press play.

How did you get on? Did you decide that it was false because smaller containers may be wider and so they may be able to hold a greater volume? Well done.

It's your turn to practise now.

For your first task, can you find five objects.

Compare the mass of your objects by holding them.

Which object feels lighter, which feels heavier? Can you start with your lightest object and arrange the objects in order of mass? And then, if you can, if you do have a set of scales, measure their mass and see if you are correct with your ordering.

And for your second question, I'd like you to solve this problem.

Jacob has a glass which is full to its capacity of 200 millilitres.

Andeep's glass has a capacity of 600 millilitres but is only half full.

What is the volume of liquid in Andeep's glass? Who has the greatest volume of liquid in their glass? And what is the difference between the volume of liquid in Andeep's and Jacob's glasses? You have two questions to have a go at.

So pause the video when you've completed both questions, press play.

Shall we see how you got on? You might have found five objects like these.

I found an egg, a cupcake, a carrot, a tomato and an orange.

And you might have held them and compared them and to see which was the lightest, which was the egg for me, and which is the heaviest, which is the orange for me, and then you might have put them in an order that looks like this, going from the lightest to the heaviest.

You might have used scales to check that you were correct and labelled each with its actual mass.

So I found the egg was 50 grammes, the cupcake, 100 grammes, the carrot, 120 grammes, the tomato, 150 grammes and the orange, 200 grammes.

So I can see there that my ordering was correct.

For question two you were asked to solve a problem.

I like to represent things in a bar model.

So when I was asked what the volume of liquid in Andeep's glass was, well I could put my whole amount, the capacity of his glass is 600 millilitres, is only half full.

Half of 600 is 300.

So the volume of liquid in Andeep's glass is 300 millilitres.

For part B, who has the greatest volume of liquid in their glass? Well Jacob had 200 millilitres and that's smaller than 300 millilitres.

So Andeep has the greatest volume of liquid.

And then the difference between the volume of liquid in their glasses, 300 millilitres is 100 millilitres more than 200 millilitres.

So Andeep has 100 millilitres more liquid.

How did you get on? Brilliant.

Well done.

Fantastic learning so far everybody.

We've really deepened your understanding on comparing mass and volume.

We're now going to move on to think about how we estimate mass and volume using objects that we might know the mass or the volume of.

If we know the mass or volume of some objects or liquids, it's easier to estimate that of others by comparing them to those that we know.

Andeep and Jacob found an object that they knew had a mass of 100 grammes.

I wonder if you can guess what it might be.

That's right, a typical apple has a mass of 100 grammes.

Maybe you can find an apple and just hold it and feel, that will be about 100 grammes.

And we can use the apple to estimate the mass of other objects without needing to use scales.

I wonder how they do that.

Do you know how they might do that? What is the mass of this stone? Ah, remember we cannot compare the mass by looking at it.

It depends on the matter inside and we can't always tell that.

But we can estimate the mass of the stone by comparing it to the mass of the apple.

"We can do this by holding the apple in one hand and the stone in the other," Jacob is telling us.

"The stone feels a little bit lighter than the apple," Andeep tells us.

"It has a smaller mass than 100 grammes." So we are now estimating the mass of the stone by comparing it to a known mass, a known mass of 100 grammes because we know that is the mass of the typical apple.

So Andeep can now estimate its mass to be about 80 grammes because that is smaller than 100 grammes of the apple because the stone feels lighter than the apple.

Andeep and Jacob found some other objects that they knew the mass of.

A typical egg has a mass of 50 grammes.

Maybe you can vary carefully find an egg and hold it, compare it to the apple.

An egg is usually about 50 grammes.

And the pound coin, if you've got one of those, have a feel of that.

Usually they have a mass of about 10 grammes.

And we can use these objects to estimate the mass of other objects without needing to use scales.

Andeep and Jacob decide to estimate the mass of different objects by comparing to these objects of known mass.

So by comparing to a pound coin of 10 grammes, an egg of 50 grammes and an apple of 100 grammes, Andeep decides to estimate the mass of a toy car that he has found.

The toy car feels heavier than the pound coin.

So he is saying its mass is more than 10 grammes.

He then compares it to the egg and the toy car feels lighter than the egg.

So it's mass is less than 50 grammes.

So we now know the mass of the toy car must be between 10 grammes and 50 grammes.

So Andeep is estimating that the mass is 30 grammes because 30 grammes is more than 10 grammes but it's less than 50 grammes.

Let's check your understanding.

Using these clues, can you estimate the mass of this spoon? The spoon is lighter than the egg.

The spoon is heavier than the pound coin.

Hmm.

Have a think about that.

Pause the video and when you think you have an estimate for the mass of the spoon, press play.

How did you get on? Did you remember that the mass of an egg is roughly 50 grammes? The mass of the pound coin is roughly 10 grammes, so the mass of the spoon must be in between 50 grammes and 10 grammes.

You might have estimated then to be 40 grammes, but really it could be anything between 10 and 50 grammes would be a correct answer.

Well done for estimating the mass of that spoon.

Andeep and Jacob now decide to look at estimating the volume of liquids.

To help them, they find objects that have known capacity.

This typical glass can hold about 200 millilitres of liquid.

You might be able to go and find a glass and fill it with some liquid and that will be about 200 millilitres.

Andeep is sharing that he knows that a teaspoon can hold about five millilitres of liquid and that we can then use these known capacities to estimate the volume of other liquids by comparing them.

Andeep has drunk some water from his bottle and he wants to estimate the volume of water remaining in this bottle.

What do you think? Andeep compares the bottle to the teaspoon.

There is more liquid than a teaspoon can hold, definitely.

So what does that mean? The volume of liquid left must be more than five millilitres.

So we are comparing the volume of water in that bottle to that teaspoon.

So from that we can see that it has to be more than five millilitres.

Now we can move on and compare the water in the bottle to the glass of water.

What do you notice? That's right.

The volume of water looks more than the glass holds.

What does that mean? That's right.

The volume of water left could be more than 200 millilitres and Andeep suggests pouring it out and he's saying that the volume of water looks more than, but near to 200 millilitres and he can use that then to estimate the volume of water that is left in the bottle.

He's saying that he estimates that the bottle still has 250 millilitres of water.

Five millilitres is less than 200 millilitres, which is less than 250 millilitres.

You can see how both boys used objects that they knew the capacity of to then estimate the volume of water left in the bottle.

Let's check your understanding.

Using these clues, can you estimate the volume of milk in this bowl? So there is more milk than a teaspoon can hold.

There is less milk than a glass can hold.

And the amount of milk looks about half the volume that a glass would hold.

Maybe talk to someone and have a discussion about these clues and see if you can come up with an estimate for the volume of milk in this bowl.

Pause the video.

When you've done that press play.

How did you get on? Did you remember that a teaspoon can hold five millilitres, so there must be more milk than that.

And a glass can hold 200 millilitres, so there must be less milk than that.

And then the amount of milk looks about half the volume.

Half of 200 is 100 millilitres.

So the volume of milk is between five millilitres and 200 millilitres.

Half of 200 millilitres is 100 millilitres.

So you might have estimated it to be around 100 millilitres.

Well done.

It's your turn to practise now.

For question one, if you are able to, I'd like you to find an apple, pound coin or egg.

If not, see if you can find another object that you know the mass of.

Can you use them to estimate the mass of at least three other objects by comparing how they feel? And then starting with the smallest, put your objects in order of mass.

Remember, we are just estimating here.

There is no need to actually measure their mass.

For question two, starting with the smallest, can you put these objects in order of mass using the clues? A lemon feels heavier than an egg, but lighter than an apple.

A pencil feels lighter than a pound coin.

An orange feels heavier than an apple.

Once you've put those objects in order, could you estimate the mass of each? And then if you are able to, can you check if you are correct using scales to measure their mass.

For question three, could you find a container with a small capacity and a teaspoon? Can you estimate how many teaspoons of water it would hold? And then use the teaspoon, can you investigate whether your estimate is accurate? Have a go at the three questions.

Pause the video and when you are ready to check your answers, press play.

Shall we see how you got on? You might have found some objects and estimated the mass of objects such as these.

I found a leaf and it felt lighter than a pound coin, so I estimated its mass to be five grammes.

I found an orange and it felt heavier than the apple.

You might have estimated its math to be 230 grammes.

Then I found a key and the key felt a little heavier than the egg, so I estimated its math to be 60 grammes.

I then put my objects in order of mass.

My leaf was the lightest at five grammes, my key at 60 grammes and my orange at 230 grammes.

Five grammes is less than 60 grammes, which is less than 230 grammes.

Question two, you were asked to put these objects in order of mass following the clues.

So the lemon feels heavier than the egg.

Okay.

The pencil is lighter than the pound coin, so that's got to be the lightest.

And the orange feels heavier than an apple.

So the lemon is heavier than an egg, but lighter than an apple, so that must be next.

And then the orange is heavier than an apple, so that must be the one with the greatest mass.

Then you might have estimated the mass of each to be.

I estimated the mass of the pencil was eight grammes, the lemon, 80 grammes and the orange, 250 grammes.

Then I actually measured the mass of each.

My pencil was seven grammes, my lemon was 90 grammes and my orange was 210 grammes.

For the third task, you were asked to find a container with small capacity and a teaspoon.

So I found a cup.

Maybe you found something like this.

I estimated that it would hold 15 teaspoons of water.

Then I checked it and I found that it actually held 20 teaspoons of water.

I wonder what you found out.

Brilliant learning today, everybody.

Really well done.

You've definitely deepened your understanding of comparing and estimating mass and volume.

We now know that the size of something does not determine how much mass or matter it has.

We know large objects do not always have a greater mass.

We know taller containers do not always hold a greater volume of liquid.

And we know that if we know the mass and volume of some objects, we can use them to estimate the mass or volume of other objects by comparing them.

It's been a pleasure learning with you today.

I look forward to seeing you again soon.