Living things and the processes of life
 The processes of life

Pupil Activity

In this activity you will create a simple model of the respiratory system. Not only will you measure the effect of narrowed airway channels, you will experience it as well.

Materials:

notebook, pen, and ruler
construction paper, scissors, and tape
balloons-large and round, that blow up to about 25 cm in diameter
plastic drinking straws, 0.6 cm in diameter, cut to 15 cm lengths
rubber bands, 2.5-5 cm in length
stopwatch or watch with sweep second hand
honey dispensed from a plastic squeeze bottle with pouring spout

Method:

• Results will be written in a table on the board or overhead projector.

• Divide into teams of four. Each team should use an inch-wide strip of construction paper and tape to make a ring 25 cm in diameter.

• Number each team member, 1 to 4.

• Each team member will need three balloons. Two of the balloons will be modified by inserting a 15 cm length of drinking straw about 2.5 cm into the opening and securing it with a small rubber band. (About eight twists will make the connection airtight and still not crimp the plastic straw.)

• Each team member takes a turn at blowing up a plain balloon.

• Number 1 will inflate the balloon until it just fills the paper ring, which is held by team member, number 2.

• Number 3 measures the time needed to inflate the balloon to the nearest second, while number 4 records the data.

• When inflation is complete, pinch the balloon shut. Reset the watch, then release the air from the balloon. Record the time it takes for the balloon to deflate completely.

• When each team member has performed the trial with a plain balloon, repeat the entire process with one of the modified balloons.

• Record the times needed to inflate the balloon to 25 cm and to deflate it completely.

• When this trial is finished, each team member takes the remaining modified balloon and squirts about 2 teaspoons of honey into the balloon through the straw.

• Gently squeeze the balloon so that the entire length of the straw is filled with honey.

• Inflate the balloon to 25 cm as before. Record the inflation and deflation times.

• Calculate the average inflation and deflation times for the three trials performed by your team. Compare the results with those from the other teams.

Questions:

In our model, the three balloons represent different conditions in the human respiratory system.

What are they?

How did narrowing the passageway and adding a thick, sticky substance affect your ability to blow up the balloon?

How do you think medicines treat an asthma attack?