Math A Lung Capacity Lab

Materials:  String for measuring, ruler, round balloons, calculator

General directions for teachers and students:

This activity is best done in pairs.  Students will need a partner to help measure the circumference of their balloon.  Suggest that the students stretch the balloon several times before attempting to blow it up.  Inform the students that they are to inhale as much air as possible and exhale into the balloon.  They are to try to empty their lungs completely, but they are not to inhale a second time.

Measure the largest part of the balloon as the circumference using the string and the ruler.  Record information on the data sheet.

Data Sheet for Students:

Data Collection Sheet       Name_____________

Record the Circumference of the balloon in CENTIMETERS:

*Find the Average Circumference from the 5 Trials__________

*Using the formula for Circumference, and your average circumference,
  find the radius.  (Solve the formula for r.)

radius = _______________

*Calculate the VOLUME of the balloon (a sphere).  Your answer will be in
  cubic centimeters (cc).  This is your experimental lung
 capacity.

Volume = ____________ cc (or ml) [1 cc = 1 milliliter]

*My height in feet and inches is _____________

*My height in total inches is _____________

*My height converted to centimeters is ___________
  1 inch = 2.54 centimeters

*My age in years is ________

Formula for Theoretical Lung Capacity:
 V = 0.041 h - 0.018 a - 2.69
where V is vital lung capacity in liters, h is your height in centimeters, and a is your age in years.

*My Theoretical Lung Capacity is _______________ liters

*Theoretical Capacity x 1000 = __________________ml

*How does your experimental lung capacity compare with your theoretical lung capacity?

Teacher Information:

This is an excellent lab.  It generates a great deal of student interest and valuable information.  It allows students to compare their actual lung capacity (experimental capacity) with the predicted lung capacity (theoretical capacity) for someone their height and age.

If a student's experimental lung capacity is less than or equal to 1000 cc (l liter), there is a good chance that their breathing has a compromised capacity.

If students notice that their breathing is "below" their theoretical capacity, they start questioning why this may be occurring.  Good discussions regarding smoking and diminished lung capacity will follow.

The formula for the theoretical lung capacity is from the American Lung Association.