Name _____________________________________________________ Period _________________
Boyle’s Law – Pressure-Volume Relationship in Gases
The primary objective of this experiment is to determine the relationship between the pressure
and volume of a confined gas. The gas we use will be air, and it will be confined in a syringe
connected to a Gas Pressure Sensor (see Figure 1). When the volume of the syringe is changed by
moving the piston, a change occurs in the pressure exerted by the confined gas. This pressure
change will be monitored using a Gas Pressure Sensor. It is assumed that temperature will be
constant throughout the experiment. Pressure and volume data pairs will be collected during this
experiment and then analyzed. From the data and graph, you should be able to determine what
kind of mathematical relationship exists between the pressure and volume of the confined gas.
Historically, this relationship was first established by Robert Boyle in 1662 and has since been
known as Boyle’s law.
OBJECTIVES
In this experiment, you will
 Use a Gas Pressure Sensor and a gas syringe to measure the pressure of an air sample at
several different volumes.
 Determine the relationship between pressure and volume of the gas.
 Describe the relationship between gas pressure and volume in a mathematical equation.
 Use the results to predict the pressure at other volumes.
Move arrow to 10ml
mark. 
PROCEDURE
1. Prepare the Gas Pressure Sensor and an air sample for data collection.
a. Check to make sure the Gas Pressure Sensor is plugged into into Channel 1 of the LabQuest2.
b. With the 20 mL syringe disconnected from the Gas Pressure Sensor, move the piston of the syringe
until the front edge of the inside black ring is positioned at the 10.0 mL mark.
c. Attach the 20 mL syringe to the valve of the Gas Pressure Sensor.
3. To obtain the best data possible, you will need to correct the volume readings from the
syringe. Look at the syringe; its scale reports its own internal volume. Be sure to consistently use the inner
black ring of the plunger to measure the volume of the syringe.
4. Click the Lab Quest App on the home page.
5. Click “Sensors” at the top of the labQuest screen. Click “Sensor Set-up”, then “CH1” and then scroll down
to choose “Gas Pressure Sensor” of “Pressure Sensor” (check which probe is attached to your LabQuest!)
6. Click “OK”
7. Click “Sensors” again and then“Data Collection”
8. Choose “Mode”- “Events with Entry”, “1”column and Name = volume and Units = mls, Click “OK)
Click “Sensors” and “Change Units” choose “atm” You should now see a pressure reading of about 0.98-1.0
on the home screen.
9. Move Piston to 5.0 mls and hold. Press Green arrow play button at the bottom left side of screen to take
pressure measurement. Hit “Keep”, and then enter in 5.0mLs., Then OK
10. Repeat this process for 7.5, 10.0, 12.5, 15, 17.5 and 20mls. Move Piston, Record and enter volumes. You
should see the pressure values changing on the right hand side of the screen.
*Note - Collect the pressure vs. volume data. It is best for one person to take care of the gas syringe
and for another to operate the computer.
*You should see the points on the graph as you add collect your pressure data.
11. Hit “Stop” at the bottom left hand side of the screen after you collect the 20ml Data point.
Data Table
Once you have collected all your data, hit the table button at the top right to see your *pressure data and enter in
the table below.
Volume (mls)
5.0
7.5
10.0
12.5
15.0
17.5
20.0
*Pressure (atm)
1/Volume
PV = Pressure x Volume
1. Click the graph button again. Fit Data to a curve: Click “Analyze” and then “Curve Fit”. Check the
“Pressure” box.
2. At the new screen, hit the “Choose Fit” menu button and choose “Power” button. This will give you
the equation of the curve. Hit “OK”
3. Record the equation for this line as y = AxB (inserting “A” and “B” from the curve fit menu
____________________________
Record the “RMSE” value for this line _____________________________________ Teacher initials____
4. Return to graph by hitting the “Graph Button” at the top of the screen. Then hit “Table” button.
5. Click the “Table” button at the top to open drop down menu.
6. Choose “New Calculated Column” Then choose A/X option. Column for X : Use Volume and A = 1
7. Name – Change to 1/volume.
8. Click “OK” to take you back to the graph screen. Now you have a graph of P vs. 1/V
9. Click “Analyze” again. “Curve Fit”, “Linear” and check “pressure”
10. Record the equation of the line as y = mx + b and insert the “m” and “b” values in for the slope and yintercept. _____________________________________________________
Record the “Correlation Number “ ______________________ Teacher’s Initials ________
11. Go back to the “Table” button and record the 1/volume data in the data table above.
12. Graph Pressure (y-axis) vs. Volume (x-axis) in the for the first graph below and Pressure vs. 1/volume
(x-axis) for the second graph below. Use proper scaling. Label the graph appropriately. Draw a curve
or line connecting all the points as you saw on the Lab Quest during the lab.
_______________________________________________________________________________________

When you are done writing down all your data. Click “File” and then “quit”, and then choose discard
the data. Disconnect the probe from the Lab Quest and return the Lab Quest to Ms. Kreisel.
Post Lab Questions: Answer the questions on a separate piece of paper. You must use complete sentences
and show all your work in order to get full credit.
1. If the volume is doubled from 5.0 mls to 10.0 mls, what does your data show happens to the pressure?
(for example: the pressure increases or decreases by what factor? Use your pressure values in your
answer. Calculate the factor it changes by. (hint: 5ml pressure÷10ml pressure value)
a. What should have happened to the pressure?
2. If the volume is cut in half from 20.0mls to 10.0mls, what does your data show happens to the pressure?
(for example: the pressure increases or decreases by what factor? Use your pressure values in your
answer. Calculate the factor it changes by.
a. What should have happened to the pressure?
3. Describe the general relationship between pressure and volume of a gas.
4. Based on your data, what would you expect the pressure to be if the volume of the syringe was
decreased to 2.5 mls? Explain your answer thoroughly or show your work using the Boyle’s law
formula.
5. Based on your data, what would you expect the pressure to be if the volume of the syringe was
increased to 40.0 mls. Explain your answer thoroughly or show your work or show your work using the
Boyle’s law formula.
6. Calculate (pressure x volume) for each data point and record the answers in the data table above. How
constant were the values PV. (Good data may show some minor variation, but the values for should be
fairly constant and they should match the slope of the line that you recorded!
7. For your plot of pressure vs. 1/volume, you recorded the “Correlation” value. A “Correlation” value of
1.000 means a perfect fit for a straight line (or that your PV values were constant). How close was your
“Correlation” value to 1.000? Be sure to include your correlation value in you answer and use a
complete sentence to answer this question!
8. What specific lab procedure errors could have occurred that would have caused the R value to be off?