PhET Simulation
Sarah Borenstein, Behavior of Gases
Learning Goals:
 Explore the relationships between pressure, volume, and
temperature.
 Create graphs based on predictions and observations.
 Make qualitative statements about the relationships between
pressure, volume and temperature.
Background Information: Air is a gas. Gases have various properties that can be
observed with our senses, including the gas pressure (p), temperature (t), and the volume
(V), which contains the gas. Careful scientific observation has determined that these
variables are related to one another. By understanding these relationships it is possible
to explain how gases behave under certain conditions.
Set-Up: Students will be working in pairs with laptops, 2 different colored pens or
pencils.
Procedure: Open pHet simulation “Gas Properties.”.
Either type in: www.colorado.edu/physics/phet or Google “phet”.
Click on “Play with Sims”, open Heat and Thermo on the left side. Select Gas Properties.
1. Without using the simulation, sketch what you think the graphs would look like using
one of your colored pencils. Note: Be sure to label your x and y-axes.
Volume-Pressure graph
Explain your reasoning for the graph’s
appearance
Volume -Temperature graph
Explain your reasoning for the graph’s
appearance
Temperature-Pressure graph
Explain your reasoning for the graph’s
appearance
PhET Simulation
Sarah Borenstein, Behavior of Gases
2. Investigate the simulation involving gas properties. Explain what happens when each
of the following is changed. Be sure to keep gravity and gas type in the container the
same.

Adding air to the container:

Changing the size of the container:

Adding and removing heat with the heat control:
3. Use the simulation to verify or correct your graphs and reasoning using a different
colored pen or pencil.
Prediction color____________
Correction color____________
4. Looking at your graphs, draw or write in your own words the relationship that exists
between pressure and volume.
5. Looking at your graphs, draw or write in your own words the relationship that exists
between temperature and volume.
6. Predict what you think the graphs will look like for each scenario, then use the
simulation to verify or correct your graphs and reasoning with a different colored
pen/pencil. Label your axes and include a key to colors you use for your predictions
and corrections.
a. Pressure VS Volume (Sea-level VS Mountain elevations): People often complain about ears
“popping” when they go up into the mountains. Explain why this likely occurs.
PhET Simulation
Sarah Borenstein, Behavior of Gases
b. Pressure VS Volume (Sea-level VS Mountain elevations): Explain what a plastic bottle of soda
would likely do if you took it up into the mountains.
c. Temperature VS Pressure: Container in ice: A rigid container filled with a gas is placed in ice.
What will happen to the pressure of the gas? What do you think will happen to the volume?
d. Temperature VS Pressure: An infected tooth forms an abscess (infected tissue) that fills with
gas. The abscess puts pressure on the tooth nerve, causing a toothache. While waiting for the
dentist, the person tries to relieve the pain by treating the infected area with heat. Will this
treatment help? Why or why not??
7. What other observations can you make with this simulation?
Test Review and Practice:
Effects of Temperature, Volume and Pressure on Molecular Spacing & Motion
Key Vocabulary- Add definitions, notes and diagrams to your journal for these terms:
Open system vs Flexible Closed System vs Rigid Closed System
Phase Change: Solid, liquid, gas
Molecule Spacing
Molecular Motion/rate of molecule collisions
Temperature
Volume
Pressure
Relationships to know:
Molecular
spacing
Flexible Closed
system (ex
balloon, syringe
Increase
temperature
Decrease
temperature
Increase
Volume
Decrease
Volume
Rigid (constant
volume) Closed
Rate of
Collision
Change in
volume
Pressure
inside system
Pressure
outside system
PhET Simulation
Sarah Borenstein, Behavior of Gases
System (ex
stoppered flask)
Increase
Temperature
Decrease
Temperature
Increase
Volume
Decrease
Volume
Open System
Increase
temperature
Decrease
temperature
Name:
E#:
pHet Sim: Gas Laws
Date:
1. Before starting the simulation, sketch what you think the graphs would look like using
one of your colored pencils. Note: Be sure to label your x and y-axes.
Volume-Pressure graph
Explain your reasoning for the graph’s
appearance
Volume -Temperature graph
Explain your reasoning for the graph’s
appearance
Temperature-Pressure graph
Explain your reasoning for the graph’s
appearance
PhET Simulation
Sarah Borenstein, Behavior of Gases
2. Investigate the simulation involving gas properties. Explain what happens when each
of the following is changed. Be sure to keep gravity and gas type in the container the
same.
a. Adding air to the container:
b. Changing the size of the container:
c. Adding and removing heat with the heat control:
3. Use the simulation to verify or correct your graphs and reasoning using a different
colored pen or pencil.
Prediction color____________
Correction color____________
4. Draw/label the relationship between
pressure and volume in a flexible closed
system.
5. Draw/write the relationship between
temperature & volume in a flexible closed
system.
6. Predict what you think the graphs will look like for each scenario, then use the
simulation to verify or correct your graphs and reasoning with a different colored
pen/pencil. Label your axes and include a key to colors you use for your predictions and
corrections.
Scenario
Graph
Explain your reasoning
PhET Simulation
Sarah Borenstein, Behavior of Gases
a. Pressure VS Volume
(Sea-level VS Mountain elevations):
People often complain about ears
“popping” when they go up into the
mountains. Explain why this likely
occurs.
b. Pressure VS Volume
(Sea-level VS Mountain elevations):
Explain what a plastic bottle of soda
would likely do if you took it up into
the mountains.
c. Temperature VS Pressure:
Container in ice: A rigid container
filled with a gas is placed in ice.
What will happen to the pressure of
the gas? What do you think will
happen to the volume?
d. Temperature VS Pressure:
An infected tooth forms an abscess
(infected tissue) that fills with gas.
The abscess puts pressure on the
tooth nerve, causing a toothache.
While waiting for the dentist, the
person tries to relieve the pain by
treating the infected area with heat.
Will this treatment help? Why or why
not?
7. What other observations can you make with this simulation?