Teachers TryScience

Suck It Up: Finding Lung Capacity

Oct 02 2014

Source: Admin

Summary Information

Keywords:

lung, breathing, air

Topic:

Biology

Estimated Time Required:

less than 1 hour

Target Grade (Ages):

Grade 7 (Ages 12-13)

Tab Wrapper

LESSON

Goals and Prerequisites

Goals:

To be able to explain the different types of lung capacities
To be able to evaluate their own experimental designs.

Prerequisites:

Students should:

Be familiar with the scientific method
Understand the basic anatomy of lungs and how gases travel through them.

Instructional Objective(s)

At the end of the lesson, students should be able to:

Design an experiment to find vital capacity, expiratory reserve and tidal volume
Compare and contrast vital capacity, expiratory reserve and tidal volume
Find lung volume by reading a graph showing the relationships between balloon diameter and lung volume
Reflect on whether the experiment they designed allowed them to find vital capacity, expiratory reserve and tidal volume.

Instructional Resources

Background:

Human lung capacity – how much air can fit in your lungs – can be measured in several ways. One way is by using a piece of laboratory equipment called a spirometer. Lung capacity can also be measured using a balloon. The data you obtain may not be as accurate as that obtained using a spirometer.

Several different lung volume measurements can be made:

Vital capacity is the largest possible amount of air that can be exhaled after drawing a deep breath.
Expiratory reserve is the amount of air that remains in the lungs after exhaling normally. (It is the extra air that can be breathed out.)
Tidal volume is the amount of air taken in or expelled during normal breathing.

Materials:

Balloons
Two rulers per student
Finding Lung Capacity Worksheet
Project Rubric

Lung Capacity Worksheet

Project Rubric (pdf)

Procedure:

Before the Activity

Get a balloon for each student, two rulers.
Determine group pairs.
Print worksheet for each student.

With the Students

Break students off into their pair groups.
Pass out balloons, rulers and worksheets.
Read through the introductory paragraph on Worksheet with the class and definitions of new terms: tidal volume, expiratory reserve and vital capacity.
Discuss how to find volume of a balloon using the “Relationship between Balloon Diameter and Lung Volume” Line Graph.
Allow students to figure out how to use their materials to find the different types of lung volumes and fill out Data Tables on worksheet.
When students have finished, they answer analysis questions on worksheet:

Compare the volumes of the balloons in part A, B and C. Which has the greatest volume: Vital capacity, Expiratory volume, or Tidal volume?
Compare your results to someone else in the room. How are their results the same or different compared to yours?
Why do you think different people have different lung volumes?
What were some of the difficulties you had in doing this lab? Do you think you made any mistakes? (If you did, explain how.)

Lung Capacity Worksheet

Extensions

Have students study how the diaphragm contracts and relaxes to facilitate gas exchange. Have them design a model for their classmates to illustrate this process.
Have students research how the circulatory and respiratory systems work together to promote gas exchange.
Have students create their own spirometer, using the Lung Capacity experiment on TryScience.org.

Assessments and Rubrics

See Project Rubric.

Pre-Activity Assessment

Define the Problem: If you were a doctor trying to measure a patient’s respiratory fitness, what methods could you use to find this out? With your groups, design a way to measure lung capacity (a measure of respiratory fitness).

Activity Embedded Assessment

Research & Investigation: Have students record their hypotheses, methods, observations, and conclusions for the investigation.

Post-Activity Assessment

Designing a way to measure Lung Capacity: Using the results of their experiment, students should:

First, brainstorm potential pitfalls of their experimental design. Would these ‘errors’ in experimental design over or underestimate lung capacity? Discuss with your group members.
After brainstorming ideas, if you were to repeat the experiment again, how would you avoid experimental errors? Why do you think different individuals in the room had different lung capacities?

Lung Capacity Worksheet

Project Rubric (pdf)

External Resources