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CHAPTER 9 LAB<br />
Boyle’s Law<br />
Apparatus Tips<br />
◆ The syringe has a removable<br />
plastic cap beneath the lower<br />
block. To ensure low friction,<br />
remove the cap, pull the piston<br />
out, lightly lubricate the cylinder<br />
wall <strong>with</strong> silicone grease, and<br />
reinsert the piston.<br />
◆ The mass load on the piston<br />
should not exceed 5 kg; masses<br />
greater than 5 kg cause the piston<br />
to twist and become unstable.<br />
Techniques to<br />
Demonstrate<br />
Show students how to replace the<br />
cap while holding the piston<br />
firmly in place.<br />
Demonstrate twisting the piston<br />
<strong>with</strong>out pushing it down or<br />
pulling it up. Explain that this<br />
helps keep the friction between<br />
the piston and the cylinder from<br />
opposing the motion of the<br />
piston.<br />
Checkpoints<br />
Step 4: Make sure students twist<br />
the piston <strong>with</strong>out exerting force<br />
on the air in the syringe.<br />
352<br />
DTSI Graphics HRW—Holt Physics 2002 Page 352 CMYK<br />
352<br />
PROCEDURE<br />
BOYLE’S LAW APPARATUS<br />
Pressure and volume of a gas<br />
2. Prepare a data table in your lab notebook <strong>with</strong> four<br />
columns and six rows. In the first row, label the first<br />
four columns Number of weights, Trial 1 Volume<br />
(cm 3 ), Trial 2 Volume (cm 3 ), and Trial 3 Volume<br />
(cm 3 ). In the first column, label the second through<br />
sixth rows 0, 1, 2, 3, and 4.<br />
3. Remove the plastic cap, and adjust the piston head<br />
so that it reads between 30 cm 3 and 35 cm 3 .See<br />
Figure 9-29.<br />
4. While holding the piston in place, carefully replace<br />
the cap. Twist the piston several times to allow the<br />
head to overcome any frictional forces.<br />
5. When the piston comes to rest, read the volume to<br />
the nearest 0.25 cm 3 . Record this value as the volume<br />
for zero weight in your data table.<br />
6. Carefully place one 1 kg mass on the piston. Twist<br />
the piston several times.<br />
7. When the piston comes to rest, read the volume<br />
and record it in your data table.<br />
Chapter 9<br />
8. Carefully add another 1 kg mass to the piston so<br />
that the total mass on the piston is 2 kg. Twist the<br />
piston several times.<br />
9. When the piston comes to rest, read the volume<br />
and record it in your data table.<br />
10. Carefully add another 1 kg mass to the piston so<br />
that the total mass on the piston is 3 kg. Twist the<br />
piston several times.<br />
11. When the piston comes to rest, read the volume<br />
and record it in your data table.<br />
12. Add another 1 kg mass to the piston. Twist the piston<br />
several times. When the piston comes to rest,<br />
read the volume and record it in your data table.<br />
13. Repeat steps 3–12 twice and record the new values<br />
in the data table under Trial 2 and Trial 3.<br />
14. Clean up your work area. Put equipment away safely<br />
so that it is ready to be used again.<br />
Analysis and Interpretation begins on page 353.<br />
Figure 9-29<br />
Step 3: Adjust the piston head to set the volume of air in the<br />
syringe between 30 cm 3 and 35 cm 3 .<br />
Step 5: Wait for the piston to come to rest before reading<br />
the volume.<br />
Copyright © by Holt, Rinehart and Winston. All rights reserved.
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