Estimating Lung Volume Worksheet for 13-Year-Olds — Middle School Science Activity

Instructions

Your amazing lungs are responsible for breathing, but how much air can they actually hold? In this worksheet, you'll learn about the different ways we measure lung volume and even try a simple experiment to estimate your own!

Part 1: Match the Lung Volume Terms

Draw a line or write the correct letter in the blank to match each term with its definition.

Part 2: Lung Volume Math

To find a person's Vital Capacity (VC), you can use a simple formula. It's the total of the three main breathing volumes added together!

Vital Capacity (VC) = Tidal Volume (TV) + Inspiratory Reserve Volume (IRV) + Expiratory Reserve Volume (ERV)

Use the formula to solve the following problems. All volumes are in milliliters (mL).

1. A student has a Tidal Volume of 500 mL, an Inspiratory Reserve Volume of 3,000 mL, and an Expiratory Reserve Volume of 1,100 mL. What is their Vital Capacity?
   Calculation: _____________________________________
   Answer: _______________ mL
   
   
2. An athlete's vital capacity is measured to be 5,500 mL. Her tidal volume is 500 mL and her expiratory reserve volume is 1,000 mL. What is her Inspiratory Reserve Volume?
   Calculation: _____________________________________
   Answer: _______________ mL

Part 3: Think About It!

Use your knowledge to answer these critical thinking questions in complete sentences.

1. Why can’t you exhale every last bit of air from your lungs? What is this "leftover" air called and why is it important?
   ____________________________________________________________________________________
   ____________________________________________________________________________________
   
   
2. A trumpet player and a person who doesn't play a wind instrument are the same height and age. Who would you predict has a larger vital capacity and why?
   ____________________________________________________________________________________
   ____________________________________________________________________________________
   
   
3. Besides exercise and musical training, list two other factors that can affect a person's lung capacity.
   ____________________________________________________________________________________

Part 4: The Balloon Experiment - Estimate Your Vital Capacity

This simple activity gives a rough estimate of your vital capacity. You will need a round balloon and a flexible measuring tape (or a string and a ruler).

Steps:

1. Stretch the balloon a few times to make it easier to inflate.
2. Take the deepest breath you possibly can.
3. Exhale all the air from that deep breath into the balloon. Do not let any air escape.
4. Pinch the balloon's neck shut and measure the diameter of the balloon at its widest part in centimeters (cm).
5. Use your measurement and the formula for the volume of a sphere to estimate your lung volume.
   (Note: 1 cm³ is equal to 1 mL)

Data and Calculation:

• Diameter of my balloon: __________ cm
• Radius of my balloon (Diameter ÷ 2): __________ cm

Formula: Volume = (4/3) × 3.14 × (radius)³

My Calculation:
Volume = (4/3) × 3.14 × ( ______ × ______ × ______ )

My Estimated Vital Capacity is approximately: _______________ cm³ (or mL)

This is just an estimate! Why might this not be a perfectly accurate measurement? (Hint: Think about the shape of the balloon and its material.)

Answer Key

Part 1: Match the Lung Volume Terms

1. C. The amount of air you breathe in and out normally, while at rest.
2. E. The extra amount of air you can force in after a normal inhale.
3. B. The extra amount of air you can force out after a normal exhale.
4. D. The maximum amount of air you can exhale after taking the deepest possible breath.
5. A. The amount of air that always remains in the lungs to keep them from collapsing.

Part 2: Lung Volume Math

1. Calculation: 500 mL + 3,000 mL + 1,100 mL
   Answer: 4,600 mL
2. Calculation: 5,500 mL - 500 mL - 1,000 mL (or 5,500 - 1,500)
   Answer: 4,000 mL

Part 3: Think About It!

1. You can't exhale all the air because of the Residual Volume. This air is important because it keeps the tiny air sacs (alveoli) in the lungs from collapsing completely.
2. The trumpet player would likely have a larger vital capacity. Regularly playing a wind instrument is like exercise for the respiratory muscles, which can strengthen them and increase the amount of air the lungs can exchange.
3. Other factors include: height (taller people usually have larger lungs), age (lung capacity often peaks in early adulthood), gender (males typically have a larger capacity than females of the same height and age), and altitude (people living at high altitudes may develop larger lung capacities).

Part 4: The Balloon Experiment

Answers will vary based on the student's own measurements and calculations.

The measurement is not perfectly accurate because the balloon is not a perfect sphere and the rubber of the balloon pushes back, which can make it harder to exhale fully compared to exhaling into the open air.