Experiment 5
LINEAR EXPANSION OF METALS
MENDEZ, JAMELLA V.
NEPOMUCENO, JANINE CAYE S.
MLS 2-4
Group 6
ROLLY O. ORAA, LPT
LUZETTE D. ORAA, LPT, MST
October 19, 2023
Very
Criteria Excellent Satisfactory Developing
Satisfactory
Neatness and Organization 6 4 3 2
Cover Page 4 3 2 1
Abstract 12 9 6 3
Introduction 8 6 4 2
Procedure 8 6 4 2
Data and Results 4 3 2 1
Interpretation of Data and Results 16 12 8 4
Conclusion 8 6 4 2
References 4 3 2 1
TOTAL ___ / 70
ABSTRACT
What is linear expansion?
What is the coefficient of linear expansion?
This experiment aims to measure the coefficient of linear expansion of some metals. Essential
apparatus used includes the PASCO Linear Expansion Apparatus and Steam Generator, Xplorer GLX,
temperature sensor, metal rods, and rubber tube. The experiment used one setup for measuring the linear
expansion of three metals, namely aluminum, brass, and copper, where manipulation and recording of
needed variables and analysis of gathered data were done. Furthermore, the results (insert results here).
These findings significantly contribute to the fundamental understanding of the coefficient of the linear
expansion of metals.
INTRODUCTION
What is thermal expansion?
What is linear expansion?
What is the coefficient of linear expansion?
What is the formula for the tube length?
What is the formula for the coefficient of linear expansion?
The experiment used various materials and apparatus such as the PASCO Linear Expansion
Apparatus and Steam Generator, Xplorer GLX, temperature sensor, metal rods, rubber tube, meter tape,
and beaker and plastic container. Moreover, the meter tape measured the original length of the metal rod
while the Xplorer GLX gathered the initial temperature of the metal rod. Finally, the variables were to
measure the coefficient of the linear expansion of metals: aluminum, brass, and copper, using the initial
and final length and temperature, along with the percentage error of metals using the gathered
experimental coefficient and the given theoretical coefficient values.
SCHEMATIC PROCEDURE
Measure the original length of the metal rod at room temperature and record it as Lo.
1
Insert the metal rod in the jacket of the expansion apparatus.
2
Insert a temperature sensor inside the foam insulator.
3
Turn on the Xplorer GLX, set to digits, and press the start button to record the temperature of
4 the metal rode as the initial temperature To.
Turn the outer casting of the dial gauge to align the zero point on the scale with the long
indicator needle.
4
Turn on the steam generator and watch the dial gauge and temperature as read by the
Xplorer GLX.
5
Read and record the final temperature Tf when the temperature has reached equilibrium
6 conditions and record the expansion of the tube length indicated by the dial gauge.
Turn off the steam generator and let the system regain its room temperature.
7
Compute the experimental value of the coefficient of linear expansion of the metal.
8
Compare the experimental value with the true value by computing the percentage error.
9
Repeat the experiment for other metal rods.
10
DATA AND RESULTS
Specimen Lo (cm) To (°C) Lf (cm) Tf (°C) ΔL (cm) ΔT (C°)
Aluminum 45.4 20.42 45.462 82.44 0.062 62.02
Brass 45.5 21.3 45.549 83.07 0.049 61.77
Copper 45.5 21.33 45.541 83.65 0.041 62.32
Specimen αexperimental (1/C°) αtheoretical (1/C°) Percentage Error
Aluminum 22.02 23x10^-6 4.26%
Brass 17.43 19x10^-6 8.26%
Copper 14.46 17x10^-6 14.94%
INTERPRETATION OF DATA AND RESULTS
The coefficient of linear expansion of metals, represented as α, is directly related to changes in
length (∆L) and inversely related to changes in temperature (∆T). This means that when the temperature of
a metal changes, the coefficient α indicates whether the material will expand when heated or contract when
cooled. This relationship is fundamental to understanding how metals respond to temperature variations.
The data provided relates to how different materials, like aluminum, brass, and copper, react to
temperature changes. We measured the initial and final sizes of these materials and noted the
temperatures they were exposed to. This helped us calculate a value called the coefficient of linear
expansion (α) for each material, both experimentally and theoretically. To see how close our real-world
measurements were to the expected values, we calculated a percentage error. Interestingly, we found
that copper had the highest percentage error at 14.94%, which means our experimental results deviated
significantly from theory. Brass wasn't far behind with an 8.26% error, while aluminum had the smallest
error at 4.26%, showing that our measurements were more in line with what we expected. These
differences could be due to measurement mistakes, variations in the materials themselves, or other
factors. To get more accurate results, we might need to fine-tune our experimental methods and further
investigate these discrepancies.
CONCLUSION
In conclusion, our examination into the linear expansion coefficients of aluminum, brass, and
copper provides insight on the unique thermal expansion characteristics of these materials. In particular,
our experimentally discovered values for, which define the extent of expansion as temperature increases,
regularly fell short of the theoretically projected values, resulting in positive percentage errors. Copper had
the greatest variation from theory, with a percentage inaccuracy of 14.94%, followed by brass at 8.26%,
and aluminum had the smallest deviation, at 4.26%. The discrepancies between experimental and
theoretical results highlight potential limitations in our experimental methodologies, instrument precision, or
material diversity. Further investigation, including possible changes in experimental procedures, is
necessary to improve the precision and accuracy of our thermal expansion data.
REFERENCES
