This document describes a procedure to experimentally determine the coefficient of linear expansion of a metal rod by measuring its change in length when heated. Safety precautions are outlined when using a hot plate and boiling water. The equipment needed includes a linear expansion apparatus to hold the metal rod, a micrometer gauge to precisely measure changes in length, and a thermometer. The procedure involves taking initial length and temperature measurements, heating the rod with boiling water, and recording the final stabilized temperature and length to calculate the coefficient using the linear expansion equation. Sources of error and comparing the experimental value to accepted values are analyzed.

1. Coefficient of Linear Expansion WCJC Spring 2015 1
Coefficient of Linear Expansion
Purpose
The coefficient of linear expansion for a metal will be determined experimentally and compared to the
accepted value.
Safety
This lab makes use of a hot plate and a water boiler and both will be brought to high temperatures. Use
caution when working with this equipment in order to avoid injury.
Equipment
 Hot plate
 Water boiler
 Plastic/rubber tubing
 Thermometer
 Linear expansion apparatus
 Meter stick
 Metal rod
 Micrometer gauge
 Paper towels
 250 mL beaker
Procedure
1. Fill the water boiler about 2/3 full of water and bring it to a boil on the hot plate.
2. Measure the initial length of the metal rod and the room temperature and record these in the data
table.
3. Assemble the linear expansion apparatus and insert the metal rod. DO NOT attach the tubing
from the water boiler yet.
4. Attach the micrometer gauge to the linear expansion apparatus, align the micrometer gauge with
the metal rod, bring them to just touch, and zero the micrometer.
5. Insert the thermometer into the appropriate hole in which it comes to rest in contact with the
metal rod.
6. Once the water in the boiler begins to boil, attach the tubing from the boiler to the linear
expansion apparatus. Prepare to catch steam coming from the apparatus using any combination of
the paper towels and 250 mL beaker.
7. The system will reach equilibrium when the temperature and the micrometer reading stabilize.
When this occurs,record these values in the data table.
8. Allow heated equipment to cool and then disassemble and return the equipment to its appropriate
place. Clean up your lab area.

2. Coefficient of Linear Expansion WCJC Spring 2015 2
Analysis
1. Use the equation for linear expansion to calculate the coefficient of linear expansion for the metal
rod.
2. Compare your experimental value for the coefficient of linear expansion to the accepted value of
linear expansion for the type of metal used. Calculate the experimental % error.
3. Is this experiment an ideal way to determine the coefficient of linear expansion? Why or why not.
Explain any possible sources of error.