• pressure sensor - absolute

• printer (optional)

Follow all safety directives given by your teacher.

1. Connect the Science Workshop interface to the computer, turn on the interface, and turn on the computer.

2. Connect the DIN plug of the pressure sensor to Analog Channel A on the interface.

3. Open the Science Workshop file titled as shown:

• The document has a Digits display of the gas Pressure in kiloPascals (kPa), a Graph display of Volume versus Pressure, and a Table of Volume and Pressure.

• Note: For quick reference, see the Experiment Notes window. To bring a display to the top, click on its window or select the name of the display from the list at the end of the Display menu. Change the Experiment Setup window by clicking on the "Zoom" box or the Restore button in the upper right hand corner of that window.

4. The "Sampling Options…" for this experiment are: Periodic Samples = Slow at 1 measurement per second and "Keyboard" sampling with Parameter = Volume and Units = mL (milliliters).

• You do not need to calibrate the pressure sensor. The pressure sensor produces a voltage that is proportional to pressure (1V = 100 kPa). The default calibration is 101 kPa equals approximately one volt.

2. Put the end of the piston of the syringe at the 20 mL line. Connect the end of the syringe to the other end of the small piece (about 2.5 cm) of plastic tubing (included with the pressure sensor).

3. Align the quick-release connector on one end of the plastic tubing with the connector on the PRESSURE PORT of the Pressure Sensor. Push the connector onto the port, and then turn the connector clockwise until it clicks (about one-eighth turn).

4. Check that the syringe and pressure sensor have a secure seal by adjusting the volume between 20 mL and 10 mL. It should get harder to push as the volume decreases.

1. When you are ready to begin the experiment, click the "REC" button to begin recording data.

• The Keyboard Sampling dialog box opens.

2. Adjust the volume of air in the syringe to 20.0 mL.

3. When the pressure reading stabilizes, type in 20.0 in the Keyboard Sampling dialog box and click on "Enter".

4. Reduce the volume to 18.0 mL. Type in 18.0 in the Keyboard Sampling dialog box and click on "Enter".

5. Continue reducing the volume by 2.0 mL, checking the pressure, and entering the new volume until your last entered volume is 10.0 mL.

6. After you enter 10.0, press the "Stop Sampling" button to end data recording.

1 Click on the Graph window to bring it to the front. Click on the "Autoscale" button to rescale the Graph to fit the data. Notice that one plot shows Volume versus Pressure and that the second plot shows Inverse Volume versus Pressure.

2. Select "Print Active Display" from the File menu to print a copy of the Graph.

3. Click on the Table to select it. Select "Print Active Display" from the File menu to print a copy of the data table.

4. If time permits, repeat the procedure. For both the Table and the Graph windows, you can choose which run is displayed by clicking on the "DATA" buttons . Be sure that you are consistent about which run is specified for all the columns on the Table or both plots on the Graph.

1. From looking at your graphs, do the pressure and volume seem to be directly or inversely proportional? Does this agree with Boyle’s Law?

2. What are possible sources of error or limitations in this experiment? For each one, try to decide what effect it might have on the experimental results.