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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.


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


  • 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.


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?

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