Lesson video

Hello, my name is Dr.

Robson.

I'm delighted that you'll be joining me in today's lesson.

Let's get started.

Welcome to today's lesson from the unit of Place Value.

This lesson is called Place Value in Imperial Units.

And by end of today's lesson, we'll be able to interpret place value in the context of imperial units.

Our keyword today is imperial.

It's a system of units for measuring which was created during the early 1800s during the British Empire.

For example, feet, miles, ounces, and gallons are all imperial units of measure.

The word imperial relates the word imperialism as an empire.

Today's lesson will include two cycles, and we're gonna start by understanding what imperial units are.

So imperial measures come from an older system for measuring things.

Some examples of imperial measurements for length include inches, which is used to give the size of a pizza, a feet, which we sometimes use to measure the height of a person, yards, which is sometimes used to measure the length of a sports field, or miles, which is often used to measure the distance of a journey.

Some examples of imperial measurements for mass include ounces, which are sometimes referred to when weighing ingredients for cooking, pounds, which are sometimes used for the weight of a baby, or stone, which we sometimes use to measure adults or children's weights.

And some examples of imperial measurements for capacity include pints.

For example, milk bottles tend to be pints, or gallons for how much petrol fits in a car or how many miles might go per gallon.

Let's check what we've learned so far.

So which of the following can be measured in miles? Is it A, length, B, mass, or C, capacity? Pause the video.

Have a go.

Press play when done.

The answer is A.

Length can be measured using miles.

Which of them can be measured in pints? A, length, B, mass, or C capacity? Pause, have a go, press play when ready.

The answer is C.

Capacity can be measured with pints.

Which can be measured with pounds? Is it A, the amount of space inside a large box? B, the height of a milk bottle, or C, the weight of a cat? Have a go, pause, and press play when ready.

The answer is C.

The weight of a cat can be measured in pounds, which can be measured in gallons.

Is it A, the amount of space inside a large box, B, the height of the milk bottle, or C, the weight of a cat? Pause, have a go, press play when ready.

Did you get it? The answer is A, the amount of space inside a large box.

well done.

Many units were originally based on practical ways of measuring things by comparing them to common objects that are around.

So for example, the unit feet was originally based on the length of a human foot.

So we could express how long something was by saying it was equivalent to three or four feet in length.

Other examples are we can express how much something weighs by saying it weighs equivalent to five or six stones.

However, a problem with that is that people have different size feet.

So what one person says as being three foot might not be the same as what someone else says as being three foot.

So during the 1800s, many of these units were standardised to create the imperial system of measurements, and now one foot is a equal to exactly 12 inches.

Most countries in the world use metric units for measuring things, such as metres, grammes, and litres.

The USA use imperial units, such as miles, pounds, and gallons.

The UK use a mixture of both metric and imperial units, depending on the context.

For example, running a 50-meter race.

The length for race might be described using metric units such as metres, but the length of a journey travel by car might be described using miles.

For example, road signs in the UK express using miles.

One thing to note is that imperial units do not use the kilo, centi, or milli prefixes like metric units do.

For example, metric units for length, such as kilometres, centimetres, and millimetres, they are all metres with a prefix kilo, centi, a milli in front of them to describe how long they are compared to a metre.

However, imperial units don't use those prefixes.

The measurements for length are miles, yards, feet, and inches, completely different words.

So let's check what we've learned.

Which of the following is an imperial unit of length? Is it A, centimetres, B, inches, or C, millimetres? Pause, have a go, press play when ready.

The answer is B, inches.

One inch is approximately the width of a thumb.

However, thumbs vary.

Which of the following is an imperial unit of mass? Is it A, kilogrammes, B, grammes, or C pounds? Pause, have a go, press play when ready.

The answer is C, pounds.

Which of the following is an imperial unit of capacity? Is it A, pints, B, litres, or C, millilitres? Pause, have a go, press play when ready.

The answer is A, pints is imperial unit of capacity.

Okay, it's over to you for task A.

This task consists of two questions, and here is question one.

Look at the units on the right hand side.

And for each one of them, decide whether it is metric or imperial and write it in the correct column in the table.

Pause, have a go, and press play when you're ready to continue.

And here is question two.

Look at each of the imperial units on the right-hand side.

For each one, decide whether it is a unit for length, mass, or capacity, and write them in the correct columns in the table.

Pause, have a go, and press play when you're ready for the answers.

Well done, everyone.

Here are the answers to question one.

Our metric units of length are metres, kilogrammes, millilitres, centimetres, kilowatts, and metric tonnes.

Now, we haven't seen kilowatts in today's lesson.

It is a unit for measuring the amount of power that an electrical appliance might use, for example.

However, we can still figure out that it's a metric unit of measure because it starts with a prefix kilo.

Or can you think of any other units that are not length, mass, and capacity, but also have kilo as a prefix? You might be thinking of for example of kilojoules, which is a unit for energy, or even kilobytes in terms of computers because it's a unit for computer memory.

All those ones with kilo, centi, and milli tend to be metric units.

Our imperial units are inches, miles, and feet, which are the common ones that we've seen in today's lesson.

Hands, we haven't see in today's lesson, that is a unit of length that is the width of a hand.

Three hands make one foot.

And hands, it's not used very much, but tends to be used to measure the heights of horses.

We can figure out that it's an imperial measure because it doesn't have kilo, milli, or centi at the start, and also it's named after a common object, like feet, for example.

Others are acres, which is a imperial unit for measuring area.

for example, of a field or a forest, and also tonnes as well.

Ton's an interesting one because there's an imperial tonne and a metric tonne.

They are spelt differently, and they also have slightly different weights as well.

An imperial tonne is just slightly heavier than a metric tonne.

So if you're ever using tonnes, just double check whether it's a metric or imperial tonne that you're working with.

And in question two, our imperial units for length are inches, yards, feet, and miles.

Our imperial units for mass are ounces, pounds, and stone.

And our imperial unit for capacity are fluid ounces, pints, and gallons.

We haven't seen fluid ounces in today's lesson.

However, it's about liquid usually, so how much liquid you can fit into a bottle, so that has to do with capacity.

Onto the second cycle of today's lesson.

I'm gonna be learning to convert between different imperial units of measurements.

Imperial measures use different multipliers to convert between different units.

This is unlike the metric system where we convert between different units by always multiplying or dividing by 10, 100, and 1,000.

For example, to convert between kilometres and metres.

We times by 1,000.

It's always 10, 100, and 1,000 when it comes to metric units.

But with imperial units, we don't use 10, 100, and 1,000 to do conversions.

We use different numbers each time, depending on which units we convert between.

It's a bit more like when we convert between different units of time, although we should note that units of time are not imperial, but a good example of where we do this day-to-day anyway.

For example, when we convert between weeks and days, we times by seven.

Convert between days and hours, we times by 24.

Between hours and minutes, we times by 60.

And minutes and seconds, by 60 again.

In each case or many of the cases, we use different numbers to convert between one unit of time and another.

That's a little bit like how the imperial system works.

For example, to convert between yards and feet we times by three.

To convert between feet and inches, we times by 12.

There are 12 inches in one foot.

And if we're going either way, we'll use division instead.

So let's look at this example.

Convert five feet to inches, and we can use a table to help us.

So if we put five feet in our table, we can see we wanna convert to inches, so we're gonna multiply by 12, and we get 60.

So five feet is equal to 60 inches.

And this table is about mass and imperial units of mass.

You can see here, to convert between stones and pounds is times 14.

Pounds to ounces is times 16.

That means there are 16 ounces in one pound.

We wanna convert 140 pounds to stone.

So let's put the 140 in the pounds column.

Look which way we're going.

We're go to the left to stone.

So we want to divide by 14.

140 divided by 14 is 10, which means 140 pounds is equal to 10 stone.

Let's check what we've learned.

So select the smallest unit of length from the options.

Is it A, one yard, B, one foot, C, one inch, or D, one mile? Pause, have a go, press play when ready.

The answer is C, one inch is the smallest of those imperial units of length.

You can see that because it's in the far right-hand side of the table, and you need 12 inches to convert into one foot, which is the next smallest one along.

It's worth noting that inches are not the smallest unit of imperial length that exist.

There are some smaller units of imperial length.

So for example, there's a unit called barleycorn, which is an imperial length, and it is named after the grain barley because it's based on the width of a dried up barley corn.

And you need three of those to make one inch.

They're not used very much, but they are still used in shoe sizes in the UK and the USA as well.

But the most common ones we tend to see day to day are inches, miles, feet, and yards, and inch is the smallest.

Next question.

Convert one mile to yards and you can use the table to help you.

Is the answer A, B, or C? Pause, have a go, press play when ready.

The answer is C.

Well done, everyone.

Next question.

Convert six yards to feet, and you can use the table to help you.

Is the answer A, two feet, B, 18 feet, C, 48 feet, or D, 600 feet.

Have a go, pause, and press play when ready.

The answer is B, 18 feet, where you take the six.

We put it in the yards column.

And because we are times in by three to convert it into feet, we got six times three is 18.

If you've got two feet, it might be that you divided by three rather than times by three.

Or if you got 48 feet, it might be that you chose the multiplier 12, rather than the multiplier of three.

And if you chose 600 feet, you might be thinking about metric and times them by 100, for example, rather than one of the units on screen there.

Next question, convert six feet to yards, and you can use a table to help you.

Is the answer A, 0.

06 yards, B, two yards, C, 18 yards, or D, 48 yards.

Pause, have a go, press play when ready.

The answer is B, two yards.

We put the six in the feet column, and because we're converting to yards, we divide by three.

Six divided by three is two.

If you've got no 0.

06, it looks like you've probably divided by 100 and you got it mixed up with metric units.

If you've got 18, it's probably about you times by three, rather than divided by three.

But we're going from feet to yards, so we need to divide by three.

And if you've got 48, chances are you chose the number 12 as your multiplier, rather than the three.

But we're going between feet and yards, so our multiplier is the three.

Okay, it's over to you again for task B.

This task consists of three questions, and here are the first two.

Question one, starting with the smallest, sort the imperial units into ascending order of size.

So write the smallest one first and then write the next biggest one and the next biggest one until the biggest one last.

In question two, you've got some information here about Jacob, but in the blanks, there needs to be some units.

Write the imperial units listed at the bottom in the appropriate blank spaces.

Pause, have a go, and press play when you're ready for the next question.

In question three, we need to convert between one imperial unit and another, and we can use a table on the right-hand side to help us with those conversions.

Pause the video, have a go, and press play when you're ready for the answers.

How do we get on? Let's look at some answers.

So starting with the smallest, sort the units into ascending order of size, our smallest is inches, then feet, then yards, and then miles.

Question two, fill in the missing words in this information about Jacob.

So Jacob is nearly six feet tall.

We tend to use feet to measure people's height.

He travels to school by getting the bus for five miles.

Miles is an imperial measurement for, good for measuring journeys, long distances.

And then he walks 30 yards.

A yard is roughly the length of a stride.

Question three, use information given to calculate the conversions.

Part A, five yards is equal to 15 feet.

That's five times three.

B, 12 feet is equal to four yards.

That's 12 divided by three.

C, two stone is equal to 28 pounds.

That is two times by 14 D, 160 ounces is equal to 10 pounds.

That is 160 divided by 16.

E, two yards is equal to 72 inches.

That is taking your two times them by three to get feet, and then times your answer by 12 to get into inches.

F, three yards and one foot is equal to 120 inches.

If we convert yards to feet first by doing three times three, making nine, we can see we've got nine foot plus one foot is 10 feet, and then we'll go do 10 feet times 12 to get inches.

That's 120.

So 240 inches is equal to six yards and two feet.

If we start at our 240 in the inches column, we divide it by 12 to make it into feet, and then we divide it by three to get to yards, we can see how many yards we can make in terms of how many feet there are.

We got six yards and two feet.

Well done, everyone.

So to summarise today's lesson, imperial units comes from an older system of measuring things.

Imperial measurements evolved over the course of history and were standardised during the British Empire.

People in the UK tend to use a combination of metric and imperial units of measure, dependent on context.

And the key thing to remember is that conversions between different imperial units are different to the metric system and use a greater range of numbers.