Inhalation and Exhalation

Kelly Ludwig Lincoln-Way High School
1801 East Lincoln Highway
New Lenox IL 60451


The main objectives of this Mini-teach are to make a model of the
respiratory system that will demonstrate the processes of inhalation/exhalation
and to determine the volume of air exhaled.

Materials Needed:

MODEL CONSTRUCTION VOLUME OF EXHALED AIR 2 pieces of plastic straw food coloring 2 small balloons water rubber cement paper towel clear plastic cup 2-L plastic bottle large balloon 2-hole rubber stopper rubber band rubber tubing tape glass tubing graduated cylinder Strategy:

Model Construction 1. Take a piece of straw and cut a hole in the middle, do not go through to the opposite side. Fit a small balloon over each end. If the balloons are slightly larger than the straw, cement them to the ends. Put this aside to dry. 2. When the cement has dried, bend the straw in the middle of the hole. 3. Take a second piece of the straw and cut a V-shape at the end. Fit the slanted points of the straw into each semi-circle of the bent straw. 4. Cement the two pieces of straw together. Allow the cement to dry. 5. Cut a hole in the bottom of the clear plastic cup using the diameter of straw as a guide. Push the open end of the straw into the hole of the plastic cup from the inside. Cement the straw in the hole. 6. Take the large balloon and cut the neck off. Carefully stretch the cut balloon sheet over the opening of the cup. Do not crack the cup. Secure the balloon sheet with a rubber band. If necessary, you may tape the edges, but do not cement them to the sides of the cup. The model will work only if there are no leaks. 7. Pull down on the balloon sheet. Observe what happens to the small balloons. 8. Push up on the balloon sheet. Observe what happens to the small balloons. Measuring the Volume of Exhaled Air 1. Fill a plastic bottle four-fifths full of water. Add several drops of food coloring to the water. 2. Put a short glass tube (does not reach the water) and a long glass tube (almost reaches the bottom of the bottle) through the 2-hole rubber stopper. 3. Connect the rubber tubing. To the short glass tube connect a piece to blow into. To the long glass tube connect a piece that will touch the bottom of a graduated cylinder. 4. Cover the opening of the shorter length of rubber tubing with a paper towel, and after inhaling normally, exhale normally into the rubber tubing. 5. The exhaled air will cause an equal volume of water to move through the outer length of tubing into the graduated cylinder. Record the volume of this water in ml in a data table. 6. Pour the colored water from the cylinder into the 2-L plastic bottle. 7. Repeat steps 4-6 two more times. Record the results in your data table. Calculate the average of the three readings. 8. Run in place for two minutes and exhale into the rubber tubing. Record the volume of the water in the graduated cylinder. 9. Rest for a few minutes until your breathing returns to normal. Then repeat step 8 two times and record the results. Calculate the average of the three readings. Performance Assessment:

At the conclusion of the Mini-teach, students will be able to answer the
following questions:
1. What do the small balloons represent?
2. What do the two ends of the straw to which the balloons are attached
3. What does the longer piece of straw represent?
4. What do the sides of the cup represent?
5. What does the balloon sheet over the cup's opening represent?
6. What happened to the small balloons when you pulled down on the balloon
7. What happened to the small balloons when you pushed up on the balloon
8. What happens in the plastic bottle as you exhale into the rubber tubing?
9. Why is it important to measure the volume of exhaled air three times
before and after exercise?
10. How does your average volume of exhaled air before exercise compare to
your average volume of exhaled air after exercise?
11. What effect does exercise have on the volume of exhaled air? Explain.


Students will understand the basic anatomy and physiology of the
respiratory system. Also, students will understand that exercise will effect
the volume of air exhaled.

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