012-08375A
Small Piston Heat Engine
7
Experiment 3: Boyle’s Law
Theory
Boyle’s law states that the product of the volume of a gas times its pressure is a constant at a fixed
temperature:
P =
a
V
➀
With the platform raised to its uppermost
position, connect the Pressure Sensor to a port on
the base apparatus with a short piece of tubing
(Figure 3.1).
➁
Close the shut-off valve on the tubing from the
unused port.
➂
Connect the Pressure Sensor to the computer
interface and set up DataStudio to record pres-
sure. Be sure that you set up the keyboard
sampling option so you can enter height data by
hand. (See “Manual Sampling” or “Keyboard
Sampling” in the DataStudio online help.)
Procedure
➀
Record the height of the piston and the pressure
when the platform is raised to its highest position.
➁
Press the platform down to a series of levels and
record the height and pressure at each level.
➂
Convert the height measurements to gas volume
measurements. (Hint: The diameter of the piston
is 32.5 mm.)
➃
Prepare a graph of pressure versus volume.
Therefore, at a fixed temperature, the pressure will be inversely related to the volume, and the
relationship will be linear:
*For details on setting up and operating the Pressure Sensor with
DataStudio software
, please
consult the instruction sheet for the Pressure Sensor and the
DataStudio online help.
PV = a
Setup
➤
Note: At pressures greater than 120 kPa, the relationship between pressure and volume may
not be linear because of air leakage from the valves and ports at higher pressures.
Figure 3.1. Experiment setup
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To computer interface
Close the shut-off
valve on the tubing
from the unused
port.
Pressure Sensor
Equipment Required:
• Small Piston Heat Engine
• Pressure Sensor (CI-6532A)
•
Science Workshop
computer interface*
• DataStudio software