PHYS 108L
Spring
2019
Lab 1: Gas Thermometer and Absolute Zero
Your Name Gloria Ge
Your Partner’s Name
Section # 02
Introduction
1. What this lab is all about?
In this lab, the relationship between pressure and Temperature for the gas is. This
experiment involved using a constant pressure gas thermometer, and a constant volume in gas
thermometer, in conjunction with the ideal gas law, to predict a temperature of absolute zero and
predict the room temperature.
.
2. What is the investigated physics principle (or model)?
The ideal gas law and absolute zero is investigated here. For a gas at temperature 0 K, there is
zero thermal motion and zero gas pressure, and it is called “absolute zero”. For this reason, the
Kelvin temperature scale is known as the “absolute” temperature scale. For an ideal gas,
if the volume, V, and the number of moles, n, are constant, write the
temperature in Kelvin, KT, as a function of pressure p. The experiment uses ideal gas law to
determine the regression line and the absolute zero.
3. Briefly describe what you did.
The experiment began with taking value so the pressure and temperature as the temperature of
the bath increase as the substance for bath is changing. We first vacuumed the air in gas
thermometer and injected the gas thermometer with helium and recorded the initial pressure
under room temperature. Then the gas thermometer was put in four different baths with various
temperature and recorded the pressure again. Repeated the process for four times with various
initial pressure. Finally took points of temperature and pressure and then plotted the graph of
Pressure vs. Temperature values.
Results
Measured room temperature = ?? unit
Measurement 1
Measurement 2
Measurement 3
Measurement 4
Pinitial absolute 147Kpa
Pinitial absolute 130kpa
Pinitial absolute 115kpa
Pinitial absolute =100kpa
T1 = 77K
P1absolute =40kpa
P1absolute = 35kpa
P1absolute = 30kpa
P1absolute = 23kpa
T2
=201K
T3
=273K
T4
=373K
P2absolute = 98kpa
P2absolute = 90kpa
P2absolute = 75kpa
P2absolute = 65kpa
Graphs
P3absolute = 135kpa P3absolute = 115kpa P3absolute = 115kpa P3absolute = 90kpa
P4absolute = 185kpa P4absolute = 157kpa P4absolute = 145kpa P4absolute = 125kpa
Calculations (You must show your work to receive credit.)
1. Average T0 and % error:
The absolute zero can be obtain from the linear regression line setting the y(pressure) as
zero and the x(Temperature) value is the absolute zero we gained.
T01=-135.11/0.4907= -275.34C
T02=-116.43/0.4089= -284.74C
T03=-107.99/0.3985= -270.99C
T04=-90.22/0.3446= -261.81C
AverageT0 = ( -275.3413+-284.7395+-270.9912+-261.8108)/4= -273.2208C
Percentage error [-273.15-(-273.2208)]/273.15= 0.0002591982=0.02%
2. Average Troom and % error:
Troom1 = (147-135.11)/0.4907=24.231C
Troom2 = (130-116.43)/0.4089=33.1866C
Troom3 = (115-107.99)/0.3985=17.5910C
Troom4 = (100-90.222)/0.3446=28.3807C
Average Troom= (24.231+33.1866+17.59097+28.38073)/4=25.8473C
Percentage error= (25.84-22.778)/22.778=0.1344=13.44%
Conclusion
From the graphs with obvious linear regression lines, we can definitely conclude that there is
positive and linear response relationship between pressure and temperature which correspond to
the ideal gas law. Constant volume gas thermometers operate on the ideal gas law, with the
restrictions that the gas thermometer remains the same volume, the pressure and temperature
values can be explored. Knowing that when the temperature of an ideal gas increases, that there
is a corresponding increase in pressure. Conversely, when the temperature decreases, so does the
pressure. Our group obtained an experimental average absolute zero temperature at -273.22C
which is really close to the actual value -273.15C, having a 0.02% percent error. At this point,
the pressure is zero and no kinetic energy if given for gas molecules. For Troom temperature, we
predict a value from the average Troom to be 25.84C from the linear regression function.
However, on the other hand, some measurement and mistakes need to be explained. For the third
trial of experiment with initial temperature115kpa, the pressure of gas thermometer should have
a value smaller than the value we obtained for gas thermometer’s pressure in to ice water since
the Temperature of ice water should be lower than the room temperature which should predict a
smaller pressure value. The reason for this inconsistence might be caused by the fact that we did
not wait until the pressure drop to the appropriate value and recorded the pressure. However, in
general our groups data confirm the positive linear relationship between pressure and
temperature, also the confirm the absolute zero around -273.15C and room temperature around
25C.
THE END