Hello, and welcome to today's lesson from the Oak National Academy.

Today's lesson is taken from the unit breathing and respiration, and we're gonna be estimating your lung volume today, it is a practical lesson.

Hi there, I'm Mrs. Wheat and I'll be taking you through today's lesson.

By the end of today's lesson, you were able to describe how to use simple apparatus equipment to estimate lung volume.

Let's have a look at our keywords.

We have five keywords for today's lesson, volume, vital capacity, accurate, meniscus, and estimate.

So I'm gonna show you definitions, and don't feel like you have to rush and memorise all of these.

If you want to pause the video and write them down or just read through them, that's totally fine.

Take your time, but here are the definitions.

Today's lesson is in three parts.

In the first part we'll talk about the apparatus equipment that's necessary for measuring vital capacity.

In the second part, we'll talk about how to use the apparatus in order to take the measurements of vital capacity, and then we'll talk about how do we use that measurement and that value in order to estimate our lung volume.

But first of all, apparatus for measuring vital capacity.

Let's start with a really quick recap of the lungs.

So when we inhale, when we breathe in, air is moved into our lungs.

You can see the lungs labelled here on my diagram, and you can see the air flowing through in that green arrow into each lung.

When we exhale, breathe out, air is moved out of our lungs.

When we exhale, most of the air is moved out of the lungs, but some stays behind.

It might feel like your lungs are completely empty, but they're not.

There is still some air there.

The maximum volume of air you can breathe out after breathing in fully is called your vital capacity.

So if I breathe in fully, (breathing in) okay, now I'm gonna breathe out fully.

(breathing out deeply) That air that I just breathed out, that's my vital capacity.

Your vital capacity is affected by several factors such as a person's age.

So babies and elderly people, they'll have a smaller vital capacity than say, teenagers and adults.

Activity levels, if you're really physically active, if you're really physically fit, then you're gonna have a larger vital capacity.

And whether they smoke, smoking will reduce your vital capacity or have asthma.

Again, you'll have a reduced vital capacity if you've got asthma.

Okay, let's see if you understood that.

Vital capacity is the maximum volume of air that, A, the lungs can hold, B, can be fully exhaled after inhaling fully, C, can be inhaled by the lungs.

So you've got five seconds now, or you can pause the video to give yourself some extra thinking time.

Click play when you're ready to see the answer.

It is B, can be exhaled after inhaling fully.

Well done if you got that right.

You can measure your vital capacity using simple apparatus.

So this is what we're gonna use today.

So a tank of water, a large bottle containing water with lines marked on the bottle, and plastic tubing.

Exhaling into the tubing moves air from your lungs and into the bottle.

Then this displaces some of the water from the bottle into the tank.

So there'll be a little bit of air that's originally in the bottle before we start breathing.

When you exhale, that's moving the air from your lungs into the bottle, you see those bubbles of air, and that displaces some of the water from the bottle into the tank.

And now we have that air that was exhaled from your lungs, that's in the bottle now.

So this is how to set up the apparatus.

So first of all, you need to measure 200 centimetres cubed of water in a measuring cylinder.

Pour 200 centimetres cubed of water into a five litre bottle.

Mark the water level on the outside of the bottle with a permanent marker.

Repeat these steps, so repeat steps one, two, and three until the bottle is almost filled with water.

Right, so if you're not paying attention, this part has the potential to go a bit wrong.

So make sure that you pay close attention.

So cover the open end of the bottle and turn the bottle upside down.

Be careful not to spill any water.

So I've got a bottle here.

This is what I could find in my recycling.

So you're putting your palm on the open end, and you're flipping reasonably quickly, so that the water's staying inside, okay? We don't want any of that spilled anywhere, otherwise you're gonna have to put all the water back in and start again, yeah? Your bottle is five litres, so it's much, much heavier than my bottle.

You might need one person to hold it and another person to put their palm on it when you flip it, 'cause it will be quite heavy.

Have a go at lifting it up to see maybe who the strongest person in your pair or your group is.

Who's gonna be more likely to flip it over without spilling it everywhere, okay? Right, once you've done that, so you're holding it, it's flipped, it's upside down, then you place the bottle into a tank of water with the open the open end of the bottle under the water.

So once the bottle, the open part is underneath the surface of the water, then you can let your hand go because then all the water, it won't spill out.

Right, then you need to insert one end of the plastic tube into the bottle and leave the other end outside the water, 'cause that's what you're gonna breathe out.

Right, okay, let's see if you understood that.

Put the steps in the correct order to set up the apparatus.

A, place the bottle upside down in the tank of water, B, pour 200 centimetres of water into a large bottle, C, measure 200 centimetres of water into a measuring cylinder, D, repeat and mark the level of each 200 centimetres of water on the outside of the container, E, insert one end of the plastic tube into the bottle.

You can take five seconds or you can pause the video to give yourself some extra thinking time.

Click play when you're ready to see the correct answers.

Okay, let's see the right answer.

So first of all, we measure 200 centimetres cubed of water in a measuring cylinder.

Then we pour 200 centimetres cubed into a large bottle.

After that, we repeat and mark the level of each 200 centimetre of water on the outside the container.

Then we place the bottle upside down in a tank of water, and then we insert one end of plastic cube into the bottle.

Great work if you've got that right.

So there's supposed to be 200 centimetres cubed of water between each of the lines.

This will only be true if the volume of water was measured accurately using the measuring cylinder.

Now in science, there's tonnes of words that we use every single day.

Physics has got a lot of them like power, energy, work.

We use those words every day, but they have a specific meaning in science lessons.

Accurate is one of those words.

So the closer the volume is to the true value, remember we want 200 centimetres of cubed in between each of those lines, the more accurate the measurement is, so an accurate measurement is one that is close to true value.

Okay, let's see if we understood that.

What does accurate mean? Does it mean, A, a measurement that's close to a true value, B, a pipette was used to add the last bit of water carefully, or C, the measurement has been repeated.

So take five seconds or pause the video to give yourself some extra thinking time.

Click play when you're ready to see the answer.

Okay, it is A, so accurate means a measurement that is close to true value.

Well done if you got that right.

So I've said it's really important to make sure that we measure 200 centimetres cubed of water really accurately.

Here's how to do that.

So look at the measuring cylinder from the side, position your eye so it is level with a 200 centimetre cubed mark.

Use a beaker to pour water into the measuring cylinder until it almost reaches the 200 centimetre cubed mark.

Then use a pipette to run water down the inside wall measuring cylinder until it reaches 200 centimetre cubed mark.

So here's a video of exactly how to do that.

How to measure volume of liquid as accurately as possible using a measuring cylinder.

You'll need a measuring cylinder, a beaker of water, and a pipette.

You'll want to measure out 200 centimetres cubed of water.

Look at the measuring cylinder from the side.

Position your eye so it's level with a 200 centimetre cubed mark.

Use a beaker to pull water into the measuring cylinder until almost reaches the 200 centimetre cubed mark.

Use a pipette to trickle water down the inside wall of the measuring cylinder until it reaches a 200 centimetre cubed mark.

You might be thinking, well, why can't I just look at the measuring cylinder from my standing position? Why do I have to crouch down and get my eye level? And I'll show you why that is.

So it is important to look at the measuring cylinder from the side and position your eye, so it is level with the mark you want to fill it to.

So this is what a measuring centre looks like from above.

Viewed from above, the volume of the liquid appears to be slightly more than 200 centimetres cubed.

But if you crouch down and you get your eye level with a 200 centimetre mark, we can see that it's actually exactly on 200 centimetres.

So if you'd viewed from above, you would actually have underfilled the measuring cylinder, and that means our result, our measurement would've been much less accurate.

You might notice that the surface of the water in a measuring cylinder is curved.

This is called the meniscus.

We read the volume of the water from the bottom of the meniscus in order to get an accurate value.

Okay, let's see if that made sense.

Which measuring cylinder contains 200 centimetres cubed of water? Is it A, B, or C? Take five seconds or click pause in order to give yourself some thinking time.

Click play when you're ready to see the answer.

It is B, well done.

We read the volume of the water from the bottom of the meniscus, that curve in the surface.

Okay, you're ready for the first practise task.

Follow the method on the worksheet to set up the apparatus.

Explain why it's important to look at the measuring cylinder from the side when measuring out 200 centimetres cubed of water.

You need to pause the video to give yourself some time to do that.

Click play when you're ready to see the answer to number two.

Okay, hopefully you found it easy to set up your apparatus.

Here's the answer to number two.

Explain why it is important to look at the measuring cylinder from the side when measuring out 200 centimetres cubed of water.

Looking from the side allows you to position your eyes, so it is level with the 200 centimetre cubed mark.

This allows you to see when the level of the water is exactly on the 200 centimetre cubed mark.

This makes the measurement more accurate, close to the true value of 200 centimetres cubed.

Well done if you got that right.

We've completed the first part of the lesson, which is all about the apparatus used for measuring vital capacity.

Now we're gonna talk about how do we use that in order to get a simple measurement of vital capacity.

To use the apparatus to measure vital capacity, start by noting which line the water level starts at.

Then exhale into the tube.

So at the top we've got the air originally that was in the bottle.

Then we're gonna exhale.

So the water from the bottle is to space into the tank, and now you can count how many lines the water levels has dropped by.

Each gap between the lines represents 200 centimetres cubed.

So here is our method for using the apparatus.

So note which line the water levels out in the bottle.

Number two, breathe in, inhale as fully as you can.

Number three, breathe out, exhale into the tube as fully as you can.

Number four, count how many lines the water level inside the bottle has fallen by.

And number five, multiply the number of lines by 200 centimetres cubed to estimate your vital capacity.

Let's practise the calculation for estimating vital capacity.

After Sofia exhaled into the tube, the water level in the bottle dropped by 14 lines.

What is Sofia's vital capacity? So if each gap between the lines represents 200 centimetres cubed, and for Sofia, the water level dropped by 14 lines, we need to do 200 centimetres cubed times by the number of lines, 14.

And that gives us 2,800 centimetres cubed.

After Andeep exhaled into the tube, the water level in the bottle dropped by 15.

5 lines.

What is Andeep's vital capacity? So look at the method that we use for estimating Sofia's vital capacity, and apply that to Andeep.

Give yourself five seconds or you can pause the video to give yourself some more thinking time.

Click play when you're ready to see the answer.

Okay, here we go.

So each gap between the lines represents 200 centimetres cubed, 200 times 15.

5, that was the number of lines that the water level dropped for Andeep, equals 3,100 centimetres cubed.

Great work if you got that right.

You're ready for the second practise task for today's lesson.

Follow the method on the worksheet to use the apparatus to measure vital capacity.

Then fill in your table with your result.

After you've done that, have a go at these questions.

So Sofia and Andeep learn in school that smoking can reduce your vital capacity.

The table shows two people with different vital capacities.

So person A has a vital capacity of 4,100 centimetres cubed.

Person B has a vertical capacity of 3,500 centimetres cubed.

Sofia says person B must be a smoker, because their vital capacity is lower.

Is Sofia correct? Explain why or why not.

Pause the video here to give yourself enough time to estimate your vital capacity and have a go at this question.

Click play when you ready for the answer to this question.

Let's have a look at the answer.

Is Sofia correct? Explain why or why not.

Sofia is correct in saying that smoking lowers your vital capacity.

Sofia is incorrect to say that person B must be a smoker.

There could be several reasons why person B has a lower vital capacity.

For example, they could be much younger or much older or much less physically fit, or they could have asthma.

Well done if you got that right.

We have set up our apparatus for measuring vital capacity.

We've used it to get a simple measurement of vital capacity, and now we're gonna use that measurement to estimate our lung volume.

So before we talk about lung volume, let's talk about that word accurate again.

Even if 200 centimetres cubed of water is measured accurately each time it's added to the bottle, the measurement of vital capacity may not be accurate, close to the true value.

So there's a couple reasons for this.

It could be that the person might not have inhaled fully before exhaling into the tube.

They might not have exhaled fully into the tube either.

The lines indicating each 200 centimetre cubed mark may not have been accurately put on the bottle.

So remember, one of the first steps was for this five litre bottle, you had to add the water and then each time you added the water, you had to draw a line.

So if you drew that line really, really thick, or if you just put that line in slightly the wrong place, that's got a knock on effect as well, that might make it less accurate.

And after exhaling, the water level, so you've exhaled into the tube, the water's been displaced from the bottle into the tank, the water level might end up in between two lines.

So what do we do if we get into that situation? So when the water level ends up between two lines after exhaling, we have to either decide which line it's closest to and then calculate the volume to the nearest 200 centimetres cubed.

Or you could use your judgement and decide how far between the lines it is, and use a decimal to calculate the volume.

So if it's halfway between 5 and 6, you could call that 5.

5.

So that's one way you could deal with that situation.

All of these factors mean the measurement of vital capacity using the apparatus may not be accurate.

It is an estimate.

An estimate is an approximate or rough value of a quantity obtained without taking accurate measurements.

We could get a better estimate by measuring the water into the bottle in volumes smaller than 200 centimetres cubed, and drawing the lines closer together.

So you could do it for every 100 centimetres cubed or every 50 centimetres cubed.

That would be more time consuming, but it would give you more accurate measurements.

You could repeat the procedure several times and calculate a mean, an average, of the measurements.

This reduces the effects of people not inhaling or exhaling fully during an attempt.

Okay, let's see if we've understood that.

What is an estimate? Is it A, an accurate measurement, B, an approximate measurement, or C, a guess? Take five seconds or click pause if you a little bit more time, and click playing when you're ready to see the answer.

Okay, it is B, an approximate measurement.

Well done if you got that right.

So I mentioned before that not all the air leaves our lungs when we exhale.

Some stays behind to stop the lungs from collapsing.

So our vital capacity is usually around 80% of our lung volume.

We can use the measurement of vital capacity to produce an estimate of lung volume.

It will only be an estimate of lung volume, because the measurement of vital capacity was an estimate, and vital capacity might not be exactly 80% of lung volume.

It can differ from person to person.

Okay, let's have a practise of estimating lung volume.

Sofia measured her vital capacity to be 2,800 centimetres cubed.

Estimate Sofia's lung volume.

So first, vital capacity is around 80% of lung volume.

So if 2,800 centimetres cubed is 80%, then to get 1%, we divide that 2,800 by 80.

That gives us 35 centimetres cubed.

So that's 1%.

We times that by 100, then, 35 times 100 equals 3,500 centimetres cubed.

That gives us 100%, and that's the lung volume.

Okay, now you try.

Andeep measured his vital capacity to be 3,100 centimetres cubed.

Estimate Andeep's lung volume.

You can take five seconds, or you can click pause to give yourself a bit more time.

Click play when you're ready to see the answer.

Okay, here it is.

Remember, vital capacity is around 80% of lung volume.

So if 3,100 centimetres cubed is 80%, to get 1%, we do 3,100 divided by 80.

That equals 38.

75 centimetres cubed.

Then we times that by 100, 38.

75 times 100 equals 3,875 centimetres cubed.

Well done if you got that.

Well done, this is our final practise task for this lesson.

Exhaling into the apparatus provides an estimate of vital capacity of the lungs.

Alex exhales into the apparatus and estimates his vital capacity at 3,000 centimetres cubed.

Number one, explain why his estimate may not be an accurate measurement of his vital capacity.

Number two, explain how Alex had used this apparatus to get a better estimate of his vital capacity.

Number three, Alex estimated his vital capacity is 3,000 centimetres cubed.

Estimate his lung volume.

Number four, explain why this estimate of his lung volume may not be accurate.

So he need to pause the video now to give yourself some time to think about that and write down your answers.

Click play when you're ready to the answers.

Alex exhales into the apparatus and estimates his vital capacity at 3,000 centimetres cubed.

Explain why his estimate may not be an accurate measurement of vital capacity.

Alex may not have inhaled or exhaled fully.

The lines may not have been marked on the bottle accurately.

The water level may end up between two lines.

The volume may have been calculated to the nearest line, to the nearest 200 centimetres cubed.

Judgement may have been used to decide how far the water level was between two lines.

Explain how he could use the apparatus to get a better estimate of his vital capacity.

Put the lines closer together, so they measure volumes smaller than 200 centimetres cubed.

Repeat the procedure several times and calculate the mean, average volume.

Alex estimated his vital capacity at 3,000 centimetres cubed.

Estimate his total lung volume.

So vital capacities are on 80% of lung volume.

So if 3,000 centimetres cubed is 80%, to find 1%, we do 3,000 divided by 80.

That equals 37.

5 centimetres cubed, and then we do 37.

5 times 100, and that equals 3,750 centimetres cubed.

Number four, explain why his estimate of his lung volume may not be accurate.

He used vital capacity to calculate lung volume.

The original value for his vital capacity was an estimate.

We can only estimate lung volume from this value.

Vital capacity is not necessarily exactly 80% of lung volume as this varies from person to person.

Great work on that practise task.

Amazing work on that practical today.

Let's recap what we've learned to make sure it sticks in our memories.

The vital capacity of the lungs is the maximum volume of air that can be exhaled after inhaling fully.

Simple apparatus can be used to measure the vital capacity.

The closer a measurement is to the true value, the more accurate it is said to be.

The apparatus provide an estimate of vital capacity.

An estimate is an approximate or rough value of a quantity obtained without taking accurate measurements.

Really hope you enjoyed today's lesson.

Take a break now, and I'll see you back real soon for our next lesson.