Lesson video

Hello, how are you today? My name is Dr.

Shorak.

I am really excited to be learning with you.

You have made a great choice to learn maths with me today.

I am here to guide you through the learning.

Welcome to today's lesson.

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

The lesson is called Estimate and then Measure Mass and Volume and Record in a Table.

We are going to deepen your understanding of the concepts of mass and volume and we are going to look at why it is important that we know how we can record in a table.

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

So, shall we find out, how do we estimate and then measure mass and volume and record in a table? These are the key words that we will be using in our lesson today: estimate and table.

I'm sure you've probably heard those words before, but shall we practise.

My turn, estimate.

Your turn.

Fantastic.

My turn, table your turn.

Brilliant.

Well done.

So when we estimate we give a value, a number or a quantity that is near enough to the true amount.

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

And a table is data.

It's a collection of numbers, words, measurements, and descriptions of things, and it's a range in rows and columns.

Today, we are looking at deepening our understanding of measuring mass and volume and recording in a table.

We're going to start by thinking about how we estimate mass and record that in a table.

These are the children who are going to help us with our learning today.

We've got Aisha, Sophia, Jacob, and Andeep.

So let's get started.

Jacob and Sophia have been asked to practise estimating the mass of objects.

I wonder if you've ever been asked to estimate the mass of an object? Good question, Sophia.

Why though? Why do we need to practise estimating? Thank you Jacob.

Estimating is important.

If we estimate accurately, it helps us check if the actual measurements are accurate.

What can we do then to practise our estimation skills, Sophia is asking? We can use objects of known mass to help.

When we estimate the mass of an object, we should compare it to an object of known mass, like a pound coin, egg, apple or pineapple.

I wonder if you knew, but the mass of a pound coin is about 10 grammes.

That of an egg is about 50 grammes.

That of an apple is about 100 grammes, and that of a pineapple is about one kilogramme.

So Jacob is saying, let's estimate the mass of this box of crayons.

And we can hold the box of crayons in one hand and an object of known mass in the other.

Jacob is saying that the box of crayons feels lighter than the apple.

I wonder what that tells us.

But it also feels heavier than the egg.

Hmm, so the crayons are lighter than an apple, but heavier than an egg.

What does that tell us? That's right.

It tells us that the mass of the box of crayons must be between the mass of the egg, 50 grammes, and the mass of the apple at 100 grammes.

So Jacob can now estimate and he says, "I estimate the mass of the box of the crayons to be 70 grammes." 70 grammes is between 50 grammes and 100 grammes.

And once the mass of an object has been estimated, we can then measure it using scales to find the actual mass.

And if the actual mass is different from the estimate, we know that we've either not read the scale correctly or we've not estimated correctly.

And that's why it's really important to estimate first it's a good check of how accurate we are being.

Jacob has read the scales, he has noticed that there are five parts in between those marked in tools of 100.

So each part must be worth 20 grammes.

The arrow is pointing to the end of the fourth part, which means the mass of the box of crayons is 80 grammes.

And this is close to his estimate.

So we can say that the measurement is accurate.

Let's check your understanding.

Jacob estimates the mass of a pair of scissors.

I estimate that the mass of the scissors is 100 grammes.

Sophia estimates the mass of the same scissors.

"I estimate that the mass of the scissors is 250 grammes." They then measure the mass of the pair of scissors using scales, and Jacob is saying the actual mass of the scissors is 90 grammes.

So Sophia saying that she's estimated the mass of the scissors is 250 grammes.

Jacob estimated the mass to be 100 grammes, and the actual masses 90 grammes.

So, whose estimate was more accurate? Have a think about it, maybe find someone to discuss this with.

Pause the video and when you are ready, press play.

How did you get on? That's right.

Jacob is saying that his estimate of 100 grammes is close to the actual mass of 90 grammes.

Sophia is saying that his estimate was more accurate than her estimate.

So she would need to revisit either the estimate or the measurement.

Something's not quite right, so she needs to check both to see which is correct.

When we estimate and measure objects, we need to be able to present the information in a way that people can interpret easily.

A table can help us to record our measurements.

No, not that sort of table.

Thank you, Sophia.

This is an example of a table.

What do you notice? That's right.

Thank you Sophia.

The table is made up of three columns.

Can you see them? We've got a column for object, a column for estimate, and a column for mass.

And Jacob is saying each column is a place to record a piece of data.

A table is also made up of rows, and the number of rows depends on how many objects are being measured.

We can see in this table we've got a row that's got the titles in and then three further rows.

And Jacob is saying that we can now write in our estimation and actual measurement of the mass, of the box of crayons.

Shall we have a go? So we can write in object, the column for object, we can write crayons.

The estimate was 70 grammes and the actual mass was 80 grammes.

So we've recorded that data in a table.

So Jacob and Sophia then decide to estimate and measure the mass of some other objects from their classroom.

And Jacob starts with a pencil.

The pencil feels a bit heavier than a pound coin.

Okay, think about what that tells us.

So he's gonna estimate the mass of the pencil to be 15 grammes.

We know the mass of a pound coin is about 10 grammes and he said that the pencil was a little bit heavier, so that's why he's estimating 15 grammes.

Ah, Sophia is reminding us we've got that table now, haven't we? We should record the estimate in the table.

There we go.

We've put our estimate for our pencil into the table.

And now that we've estimated we can measure the actual mass and record that in the table.

Jacob measures the mass of the pencil using scales.

Can you see what the mass of the pencil is? That's right, the pencil has a mass of 10 grammes.

So we can now record that measurement for the mass of the pencil into the table, and we can check the measurement is close to the estimate 10 grammes is quite close to 15 grammes, isn't it? So it must be accurate.

Sophia finds a ball of string to estimate the mass of.

An apple is about 100 grammes.

The ball of string feels a little heavier than the apple.

What does that mean, hmm.

hair's gonna be a little bit more than 100 grammes then, isn't it? A pineapple is about one kilogramme.

The ball of string feels a lot lighter than the pineapple.

What does that mean? That means yes, that's right, that the mass of the ball of string must be between 100 grammes and one kilogramme, but probably nearer to 100 grammes, because it was a lot lighter than the pineapple.

So Sophia estimates that the mass of the ball of string is 200 grammes.

Thank you, Jacob.

Remember to record the estimate in the table.

There we go, Sophia records her estimate for the mass of the string in the table.

Now that we have estimated the mass of the string, we can measure its actual mass.

Sophia measures the mass of the ball of string using scales.

Have a look at the scales.

Can you work out what the mass of the ball of string is? Sophia is saying that ball of string has a mass of 100 grammes.

What do you think? Do you agree with that? And Jacob is reminding us we need to revisit our estimation to check if this is an accurate measurement.

Let's have a look at the table.

So Sophia puts her measurement for the matter of the ball of string into the table.

What do you notice? Yeah, the measurement of 100 grammes is not that close to the estimate of 200 grammes, is it? Hmm, what does this mean? Yes, we will need to measure the mass again to check the measurement, but something's not quite right there.

Sophia repeats measuring the mass of the ball of string using scales.

Can you spot what Sophia's mistake was? That's right.

She thought the unmarked intervals were going up in hundreds, but they're not are they? There are four equal parts between the marked intervals of one kilogramme.

So each part must be worth 250 grammes.

So what does that mean about the mass of the ball of string? That's right, the mass of the string is actually 250 grammes.

Sophia can now correct her error in the table.

The matter of the string is actually 250 grammes.

There you go, she's changed it in her table.

The new measurement is now close to the estimate, so it must be accurate.

So this is why it's really important that we estimate when we measure, just so we can check our measurements.

Let's check your understanding.

So Sophia and Jacob repeat this process for one more object.

Have a look at the table.

Can you tell me what the 200 grammes represents, and what does the 210 gramme represent? Pause the video and you might want to have a discussion with somebody about this, and when you are ready, press play.

How did you get on? Did you say that the 200 grammes represents the estimate for the mass of the toy car, and the 210 grammes represents the actual mass of the toy car? Well done.

Your turn to practise now.

For question one, could you look at these objects? You've got table, apple, pencil and laptop for.

Part A, starting with the smallest, could you put them in order of mass? And for part B, can you explain why you've put them in that order? For question two, could you find four objects and record their names in the table provided? Can you estimate their mass and record your estimate in the table? Can you measure their mass using scales and record the actual mass in the table? And then can you compare your actual measurement against your estimate? Does your estimate support your actual me measurement? And then just put yes or no in the final column of the table.

If you do not think your values agree, have a think.

Do you need to review your estimate or do you need to remeasure the mass of the object? This is the table in which I'd like you to record your estimates and measurements in.

You can see there are four columns for your object, your estimate, your mass, and your comparison.

Yes or no were the estimate and mass close or not.

Pause the video, have a go at both questions, and when you are ready to look at the answers, press play.

How did you get on? Should we have a look? First, you were asked to stop the smallest and put these objects in order of mass.

So we have the pencil, the apple, the laptop, and the table.

And you might have said something like this, a pencil would feel lighter than an apple, which would feel lighter than a laptop.

The table would feel the heaviest and would have the larger mass.

For question two, your table might look something like this.

I found a carrot, a tomato, a banana, and a grape.

I estimated their masses, and then I actually measured their mass using scales, and then I had to compare my actual measurement against my estimate.

I noticed that actually my measurements were close to each other, so I didn't need to review my estimate or remeasure the mass of the object.

How did you get on? Brilliant.

Fantastic learning so far, everybody really impressed with how you are deepening your understanding of estimating mass, and then recording in a table.

We're now going to move on and do something similar, but we're going to look at volume instead.

Aisha and Andeep want to practise estimating the volume of liquids.

Aisha is reminding us that estimating is an important skill that we use every day.

Andeep is saying that he agrees, because if we don't estimate, we might make mistakes.

We might pour a drink into a container that is not large enough.

Oh dear.

And that would be messy, right Aisha? We need to estimate to ensure make mistakes like this do not happen.

When we estimate the volume of a liquid, we should compare it to a liquid of known volume like that in a teaspoon, a glass of orange squash, or a jug of juice.

So my teaspoon we know holds about five millilitres, a glass would hold about 200 millilitres, and a jug about one litre.

So we can compare other volumes to these.

Andeep is saying that the volume of tea looks more than the volume held by a teaspoon.

What does that mean? He's also saying that it looks less than that of a glass of orange squash.

So what does that mean? That's right.

It means that the volume must be between five millilitres and 200 millilitres, and Andeep is estimating the volume of liquid in the cup to be 80 millilitres.

Once the volume of liquid has been estimated, it can be measured using a measuring jug and you can see that Andeep has poured the tea into the measuring jug.

Can you see what the volume is? That's right.

The volume of liquid in the cup is 100 millilitres.

So we know that that is close to our estimate of 80 millilitres, so our measurements are accurate.

We can now record the estimate and actual measurement in a table.

As my table got the odd, the object with tea and we estimated 80 millilitres, and the actual volume was 100 millilitres.

Let's check your understanding: Aisha and Andeep repeat this process for a jug of water.

Have a look at the table.

Can you tell me what the 800 millilitres represents and what the 900 millilitres represents? So you might want to find someone to have a discussion with.

Pause the video When you've done that, press play.

How did you get on? Did you say that the 800 millilitres represents the estimate for the volume of water in the jug, and the 900 millilitres represents the actual volume of water in a jug.

Well done.

It's your turn to practise now.

For question one, could you find three small containers and put some water in them? Don't worry about how much, just put some water in them.

Can you estimate the volume of water in each by comparing to a teaspoon or a glass? And record your estimate in the table.

Then can you measure the volume using a jug and record that in the table? And then I'd like you to compare your actual measurement against your estimate.

Oh, there you close.

Does your estimate support your actual measurement? And record yes or no if it does.

If you've put no, you might want to rethink, do you need to review your estimate or remeasure the volume? This is the table I would like you to record your estimates and measurements in.

You have four columns.

One to record your container in, one for your estimate, one for your volume, and one as a comparison to say yes or no.

Was your estimate close to your actual volume? For question two, can you answer these questions about the data in the table? Which volume is greatest? Which volume is smallest? What is the actual volume of milk? What does the one litre represent? Could you list the objects in order of volume from smallest to greatest? And what is the difference in volume between the estimate and actual volume of the squash? This is the table that I would like you to answer those questions about.

So pause the video, have a go at both questions, and when you are ready to hear the answers, press play.

How did you get on? Shall we have a look? First, you are asked to find three small containers and put some water in them, estimate and measure their volume.

So your table might look something like mine.

I found a jug.

I estimated 200 millilitres and actually it had 250 millilitres in it.

I found a cup, which I thought had 100 millilitres in it, and it actually had 80 millilitres, and I found a water bottle that I thought had 150 millilitres in, and it actually had 100 millilitres in.

I then compared my estimate to my actual volume, and I noted that my measurements were pretty close to each other, so I didn't need to review the estimates or remeasure the volume.

I wonder how you got on.

For question two, you had to answer questions about data in the table.

Which volume was the greatest? Well, the squash had the greatest volume at two litres, 300 millilitres.

Which volume was the smallest? The tea had the smallest volume at 100 millilitres.

The actual volume of the milk was one litre, 200 millilitres.

The one litre represents the estimate for the volume of the milk, and the objects in order from smallest to greatest, well, the tea was the smallest volume, then the water at 900 millilitres, milk, one litre, 200 millilitres, and the squash at two litres, 300 millilitres.

And then you are asked to find out the difference in volume between the estimate and actual volume for the squash.

While the estimate was two litres, the actual volume is two litres, 300 millilitres, and we could represent this in a bar model.

So I can see that I need to find the missing part.

And so I can see that the difference in volume is 300 millilitres.

How did you get on with those questions? Brilliant, fantastic learning today, everybody.

You really have deepened your understanding on how we can estimate and measure mass volume and the importance of recording in the table.

We've learned that estimating is important, because if we estimate accurately, it helps us check if our actual measurements are accurate, and we know that we can record our measurements in a table, and that is a way to present the information so people can interpret the data easily.

So really well done with your learning today and I look forward to learning again with you soon.