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LAB in Temperature, Gas Laws, Pressure, Molecular Motion, Kinetic Molecular Theory, Intermolecular Forces, Volume. Last updated September 06, 2019.


In this lab, students will better understand what causes pressure in a container and the variables that affect pressure (volume, temperature, number of moles) by mimicking molecular motion of gases.

Grade Level

High school


By the end of this lesson, students will

  • Understand the relationship between pressure and volume.
  • Understand the relationship between pressure and temperature.
  • Understand the relationship between pressure and moles.

Chemistry Topics

This lesson supports students’ understanding of

  • Pressure
  • Gas laws


Teacher Preparation: 5 minutes

Lesson: 30 minutes


  • Large rope
  • Timer


Students will come into contact with each other during this activity.

Teacher Notes

Students learn better by doing. This activity allows students to experience "pressure" by taking on the role of a gas particle. Students have fun and learn some important facts about gas pressure.

For the Student



Pressure is caused by the number of collisions between molecules and the force of these collisions. When there are more collisions, the pressure is higher. There are three things that can affect the number of collisions.

1) Size of the container

2) Temperature

3) Number of molecules

You will look at how these three factors affect the number of collisions and therefore affect the pressure of a gas.


For each of the following parts, you will need a long rope and four students to hold the rope in a square shape. Each student holding the rope will count the number of “gas molecules” (student volunteers) that collide with the wall of the container during a time period of one minute for each trial.

Gas molecules should remember the following:

1) Gas molecules travel in straight path until acted upon by the wall of the container or another gas molecule. They do not turn to avoid or cause a collision.

2) Gas molecules move at constant random motion. So you should not change your speed or stop during the duration of a trial.

3) Gas molecules are not attracted to or repelled by each other. So you should not change directions to hit your classmates.


Container size and pressure: Gas molecules should move at room temperature.

Container Size

Number of collisions

Trial 1 Trial 2 Average

Small container

Large container


Temperature and pressure: Gas molecules should speed walk for high temperature and walk slowly for low temperature.


Number of collisions

Trial 1 Trial 2 Average

High Temperature

Low Temperature