measuring lung capacity

Measuring lung capacity

Aim:

To measure the vital capacity (VC) and tidal volume (TV)then by using graphs and comparing the result of this experiment between student of a class to find out the relation of vital capacity (VC) and lung volume with height and weight of a person. In additional to understand how other things as exercise, sex, height and weight can affect the lung capacity and vital capacity (VC).

Introduction:

In this experiment we measure the vital capacity (VC) and the tidal volume (TV) of lungs, this actual number can then be compared with a number derived from an equation that measures vital capacity (VC). The vital capacity (VC) is the maximum amount of air moved in and out of the lungs. The tidal volume (TV) is the amount of air that you move in and out of your lungs while breathing normally. This amount of air provides enough oxygen for a person who is resting.

It surely depends on how active is the person, because a bigger human has more cells and more cells means it requires more energy(ATP),therefore the body needs to respire more and faster and as we know it is linked to lungs volume.

Prediction:

The most important thing is that how big is the person. The bigger and taller the person the bigger the capacity.

Independent variable:

Independent variable is what depends on our measurements and how accurate we are.

In this experiment this is the balloon diameter which changes and depends on out measurement

Dependent variable:

That is the height and weight of the person that we measure to find out the body surface area and afterward for calculating the vital capacity (VC).

Method:

We use two ways to calculate the Vital capacity (VC). First way is to ...

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Prediction:

The most important thing is that how big is the person. The bigger and taller the person the bigger the capacity.

Independent variable:

Independent variable is what depends on our measurements and how accurate we are.

In this experiment this is the balloon diameter which changes and depends on out measurement

Dependent variable:

That is the height and weight of the person that we measure to find out the body surface area and afterward for calculating the vital capacity (VC).

Method:

We use two ways to calculate the Vital capacity (VC). First way is to use a balloon and find out the TV and VC by that. To measure the TV:

Stretch a round balloon several times to stretch it out. Then inhale normally and then exhale normally into the balloon( you need to seat down when you doing it, because as we mentioned in introduction TV is the amount of air you move in and out when you are resting. Therefore even when you stand it can increase your lungs volume a bit more.). After that measure the diameter the balloon.
Repeat this 3 times and record it in a data table.

To measure your VC:

Repeat the procedure, only this time inhale as much air as you can and then exhale forcefully.
Record three measurements in your data table.

At the end convert diameter to a volume using lung volume – balloon diameter graph.

Now you need to work out the VC. To calculate the VC you have to find your body surface area (BSA):

BSA (m2) = ([height (cm) x weight (kg)] / 3600)1/2

Once you have calculated your BSA a second equation will show your estimated VC

Males: BSA x 2500

Females: BSA x 2000

The second way to calculate the VC is to use spirometer.

To use spirometer:

Set end of mouthpiece to nozzle
Hold spirometer by one hand and confirm that the indicator points zero
Inhale deeply stretching your body upward
When lungs are full, set mouthpiece between your lips. Breathe strongly in one motion, without leaking. You should breathe out as long as possible, within 5 or 6 minutes.
After that read measurement.
Repeat it three times.

Diagram:

Safety:

When you want to use spirometer make sure that you are using a new one.

Fair test:

The fair test is when you change only one thing and keep other things same.

In this experiment we are changing the height and weight by using the result of many persons to find out how the size of a person can affect the vital capacity (VC).but we should measure as accurate as possible because it makes our result more reliable.

Result:

Analysis:

According to above tables and the first formula, firstly the vital capacity (VC) depends on the height and weight of the person. The heaviest and tallest person’s VC is the biggest VC.

The second formula (which shows us how to calculate the vital capacity (VC)) shows that there is a different between males and females. Because we have multiplied the surface area of a male by 2500 and for females by 2000, it shows that sex is another factor which the VC depends on.

If we look more carefully at the last table we can see some exception. As an example some of the students are not as tall or heavy as the others but they have larger lungs volume. It shows that the there is another factor. Exercising and training can deeply influence the VC.As we mentioned before an athlete’s lung has been adapted to provide more oxygen for cells and muscles.

Evaluation:

We used two ways to fid out VC. In one of them we used hand measurements. It would be much better if we had used more accurate tools or a better balloon. Because the balloons were not really round. Another thing about using a balloon is that we have surfactant between our alveoli cells, therefore it make it easier for us to breathe in, but when we blow in a balloon there is no surfactant; thus it harder than breathing. In additional we can not avoid leaking. Because even if we try to send all the air from our lungs to the balloon it is still hard to keep all of them in the balloon because the balloon has little holes on its surface.

At the end I think the spirometer was more accurate than the balloon.