Introduction

Take a deep breath in. Can you feel your lungs expand? The maximum amount of air that your lungs can hold is called your lung capacity.

Many factors influence a person's lung capacity, including age, height, gender and the altitude of where you live. Lung capacity can be increased through exercise and breath training. It can be reduced by disease, smoking and exposure to air pollution.

A simple way to measure your lung capacity is to take a deep breath and exhale into a balloon. The volume of air in the balloon gives a fairly good estimate of your lung capacity.

The amount of air that you move in and out of your lungs while breathing normally is called TIDAL VOLUME. This amount of air provides enough oxygen for a person who is resting. It is possible to inhale and exhale more forcefully - the maximum amount of air moved in and out of the lungs is called the VITAL CAPACITY. 

Aim

To estimate your vital lung capacity and compare it to the mean, median and mode of your class.

Materials

• spherical party balloons

• 30 cm ruler

• optional: calculator

Method

1.Blow up the balloon to a medium size and let the air out. Repeat two more times. This will stretch the rubber so that it is not too stiff for your test.
Note: Make sure everyone completes this step the same to ensure a fair test.

2.Take the biggest, deepest breath you can manage.

3.Exhale once as fully as you can into the balloon. Tie a knot in the end, being careful not to let air escape.

4.As shown in the diagram, place the balloon alongside a ruler. Measure its diameter at the widest point, making sure your eyes are level with the top of the balloon.

5.Use the graph below to estimate the balloon's volume based on its diameter. Round to one decimal place.

The balloon's volume provides an estimate of your lung capacity.

Results

1. Share your estimated lung capacity with the class(use live brainstorm in stile).

Analysis

2. Calculate the mean lung capacity for your class. Show all working out. Round your answer to one decimal place.

3. Determine the median lung capacity for your class. Show all working out.

Note: If necessary, round your answer to one decimal place.

4. Identify the mode for the lung capacities of your class.

Note: Construct a frequency table to help you find the mode.

5. Use the three measures of central tendency to explain whether your lung capacity is higher or lower than the class average. 

6. How might an athlete's (such as skin-diver) vital capacity compare to a non-athlete? Explain your reasoning. 

Reflection

7. Identify some limitations of the method used to estimate lung capacity and suggest improvements that would increase accuracy.

7.Research:

Label the diagram of the respiratory system.

nose, trachea, diaphragm, mouth, bronchus, bronchioles, alveoli