GAS FRAME CURRICULUM
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Name_______________________________Teacher___________________________________
Gas Lab with the Frame
This lab combines real objects with a computer simulation of gas molecules. Your task is to
connect these two levels – the everyday and the tiny – into an understanding of the behavior of
gases. The “Frame” is like having super-magnifying glasses. You can observe and manipulate
simulations of very, very small gas molecules that you wouldn't be able to see and interact with
otherwise. Make sure that you have a Frame set up at your lab station.
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Try out the simulation
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Double-tap the Gas Frame icon on the desktop. The model shows a chamber with a piston
filled with gas. To start with, the gas molecules are invisible.
Tap the Reveal button to show the gas molecules represented by small green dots.
Tap the Run button to see the gas molecules’ behavior. The arrows on the piston wall
represent the impulses of collision between the gas molecules and the piston wall. Longer
arrows represent stronger collision impulses.
Tap the Energy button to show colors that represent the kinetic energy of the molecules: red
for high energy, pink for medium energy, and white for low energy.
Tap the Trace button to highlight one molecule and see its trace.
Tap the Velocity button to show arrows that represent velocity of the molecules. Longer
arrows mean greater velocity.
To turn off these visual modes, just tap these buttons again.
To pause the simulation, just tap the Run button again.
To restart the simulation, tap the Reset button.
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Some simulation results are shown on the lower right of the screen.
 Temperature of the gas is measured in Kelvin. Make sure the simulation is running. Touch
the temperature sensor tip on the left edge of the Frame and observe the temperature change.
(Note: The temperature range has been purposely exaggerated in order for you to observe
more dramatic changes.)
 Pressure of the gas is measured in an arbitrary unit. Increase or decrease the pressure by
pushing or pulling the spring attached to the right edge of the Frame and observe the
pressure change.
 Volume of the gas is represented by the location of the piston on the ruler.
 Number of molecule A starts at 100, and number of molecule B starts at 0. Pump in or take
out molecules by pushing or pull the syringe attached to the left edge of the Frame and
observe the change of number of molecules.
 Tap the small rectangle marked with “A” or “B” near the nozzle on the left edge of the
screen to switch to molecule B or A. The mass of molecule B is four times of that of
molecule A.
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Behavior of an individual molecule
In this activity, you will investigate the behavior of an individual molecule. Reset and run the
simulation, reveal the molecules, and trace one molecule. Observe this one molecule carefully
and answer the following questions.
2.1 What happens when the molecule collides with the piston wall?
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2.2 What happen when the molecule collides with another molecule?
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2.3 Why is the molecule’s speed always changing?
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2.4 Why is the molecule’s kinetic energy always changing?
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Temperature
In this activity, you will investigate the nature of temperature of a gas. Temperature (T) is a
measure of the average kinetic energy of the molecules. An individual molecule’s kinetic energy
(k) is proportional its mass (m) and its velocity squared (v2). The formula for kinetic energy is:
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𝑘 = 𝑚𝑣 2
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3.1 Reset the simulation and DON’T run it yet. Answer this question first and you will have a
chance to revise your answer later. The picture below shows gas molecules at room temperature.
The arrows represent molecules’ speed and direction. Draw how you think the molecules would
look in a cold room and a hot room.
Room temperature
Cold room
Hot room
3.2 Run the simulation and reveal the molecules. Change the temperature of the Frame by
touching hot or cold jars next to the temperature sensor (ask teacher for hot water and ice cubes).
When you increase or decrease the temperature, do all molecules have the same speed?
☐YES ☐NO
3.3 When you decrease the temperature, do all the molecules
A. spread out more.
B. gather together in the middle.
C. fill the chamber the same as before.
3.4 What happens to the average speed of the molecules when you increase or decrease
temperature?
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3.5 Based on your observation, would you change your drawing of molecules in a hotter or
colder room? ☐YES ☐NO
Explain why or why not and provide new drawings if needed.
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Cold room
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Hot room
Pressure
In this activity, you will investigate the nature of pressure of a gas. When a molecule collides
with the piston wall, it exerts a force on it. The total force on the piston wall is the sum of forces
exerted by individual molecules. Pressure (p) is defined as the force (F) on a given surface (A).
𝐹
𝑝=
𝐴
4.1 Reset and run the simulation. DON’T reveal the molecules yet. Follow the instruction and
answer this question first. You will have a chance to revise your answer later. Make sure the gas
temperature is constant. You need to move the hot or cold jar away from the Frame and wait until
its temperature returns to room temperature (around 300 Kelvin). Add 100 gas molecules into the
chamber while keeping the piston at its original position. As the number of molecules increases,
it becomes harder and harder to control the piston. What do you think happens inside the
chamber that makes the gas pressure increase? Please draw to help you explain.
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100 molecules
Before adding molecules
200 molecules
After adding molecules
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4.2 Now, reset and run the Frame and repeat what you did in 4.1 with the gas molecules revealed,
and observe what happen that makes the gas pressure increase. Was your answer correct?
Describe the evidence that either support or revise your answer. Provide new drawings if needed.
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100 molecules
Before adding molecules
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200 molecules
After adding molecules
Relationship between pressure and volume at constant temperature
The kinetic molecular theory of an ideal gas predicts the following relationship:
𝑃𝑉 = 𝑛𝑅𝑇
Where P is pressure, V is volume, n is number of molecules, R is a constant, and T is temperature.
As you explore the model, see if this relationship holds up for this model of an ideal gas.
In this activity, you will investigate the relationship between pressure and volume of a certain
amount of gas at constant temperature. You will collect data using the Frame, display your data
in a line graph, draw a conclusion based on your data, and explain your finding based on what
you know about behavior of molecules.
5.1 Data collection: First, reset and run the Frame. To find out the relationship between volume
and pressure, you need to control other variables that may confound your results.
1. Make sure that the chamber only has a single type of molecule.
2. Keep a fixed number of molecules in the chamber—no molecules being pumped in or
sucked out.
3. Keep the temperature constant.
Change volume by pushing or pulling the spring and then wait for at least 10 seconds while
holding the spring in the new position for the simulation to reach equilibrium. Because the piston
always fluctuates, you should record an average value. Repeat this procedure for at least five
volume values. Record your data below and graph the data to determine the relationship.
GAS FRAME CURRICULUM
Trial #
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Volume
Pressure
1
2
3
4
5
5.2 Display your data in a line graph below. Use the average values from each trial.
25
Pressure
20
15
10
5
0
5
10
15
Volume
20
25
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5.3 Based on your data, what is your conclusion about the relationship between pressure and
volume at constant temperature? Does your finding match what would be expected for an ideal
gas where PV = nRT?
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5.4 Explain why the relationship between pressure and volume exists based on what you know
about the behavior of molecules. Draw to help you explain.
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Gas
Before pushing the piston
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Gas
After pushing the piston
Relationship between temperature and volume at constant pressure
In this activity, you will investigate the relationship between temperature and volume of a certain
amount of gas at constant pressure. This time, you will design your own experiment. Then you
will collect data, display your data in a line graph, draw a conclusion based on your data, and
explain your finding based on what you know about the behavior of molecules.
6.1 Create a method you will use for this investigation and describe it below. You may use the
method described in 5.1 as a reference. Ask teacher for help if you need (Hint: you may use four
different temperatures: room temperature, temperature of your fingers, temperature of the cold
jar, and temperature of the hot jar.)
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6.2 Record your data in the table below.
Trial #
Temperature
Volume
1
2
3
4
6.3 Display your data in a line graph below. Use the average values from each trial.
25
Volume
20
15
10
5
200
250
300
350
400
Temperature
450
500
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6.4 Based on your data, what is your conclusion about the relationship between temperature and
volume at constant pressure? Does your finding match what would be expected for an ideal gas
where PV = nRT?
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6.5 Explain why the relationship between temperature and volume exists based on what you
know about molecules’ behavior. Draw to help you explain.
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Gas
Gas
Before being heated
After being heated
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7 Does the mass of molecules affect gas pressure at constant temperature and
constant volume?
In this activity, you will investigate whether the mass of molecules affects gas pressure at
constant temperature and constant volume. This time, you will first make a prediction based on
what you have learned so far. Then, you will design your own experiment, collect data, draw a
conclusion based on your data, and explain your finding based on what you know about the
behavior of molecules.
7.1 Based on what you have learned so far, do you think the mass of molecules (heavy
molecules versus light molecules) affects gas pressure at constant temperature and constant
volume?
A. The heavier gas molecules are, the higher gas pressure is.
B. The heavier gas molecules are, the lower gas pressure is.
C. The mass of molecules does not affect gas pressure.
D. It is impossible to know how the mass of molecules affects gas pressure.
Explain your prediction:
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7.2 Create a method you will use for this investigation and describe it below. Remember, in the
simulation, the mass of molecule B is four times of that of molecule A. Ask teacher for help if
needed.
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7.3 Record your data below.
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7.4 Based on your data, what is your conclusion about the effect of mass of molecules on gas
pressure at constant temperature and constant volume? Does your finding match what would be
expected for an ideal gas where PV = nRT?
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7.5 Explain why or why not the mass of molecules affect the gas pressure at constant
temperature and constant volume. Draw to help you explain.
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Gas
Gas
Heavy molecules
Light molecules
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Partial pressure
In this activity, you will investigate the pressure of a mixture of gases. In a mixture of gases,
each component gas has a partial pressure, which is the pressure that this component gas would
exert if it were alone in the container. Students from another school concluded from their
experiments that the total pressure of the gas mixture is the sum of the partial pressures of all
component gases (as shown in the figure below). You will first evaluate this conclusion based on
what you have learned so far and explain your evaluation. Then, you will design your own
experiment, collect data, draw a conclusion based on your data, and explain your finding based
on what you know about the behavior of molecules.
pA = pressure when type-A
molecules are in the chamber
pB = pressure when type-B
molecules are in the chamber
ptotal = pA + pB
8.1 Do you think you will reach the same conclusion about total pressure and partial pressure?
Why or why not?
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8.2 Create a method you will use to test the relationship between partial pressure and total
pressure and describe it below. Ask teacher for help if you need.
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8.3 Record your data below.
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8.4 Based on your data, what is your conclusion about relationship between partial pressure and
total pressure?
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8.5 Explain your conclusion based on what you know about the behavior of gas molecules.
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