Temperature
Physics 102
Professor Lee Carkner
Lecture 1
Things to Know
Physics 102: Principles of Physics
Professor Lee Carkner
Thing you will need
Giancoli, “Physics”, 6th edition
Scientific calculator
Bring both to class
Lab manual
WebAssign card
 Help session:
 TBA (Hopefully Tues, Thurs evenings)
Lab section
If you need to add a lab or change labs, fill out lab
form
Labs start this Thursday!
How Does the Class Work?
 Read the book material before class
 Do the WebAssign homework
 Before class
 Download and print out class notes
 http://helios.augustana.edu/~lc/ph102
 Be sure to set as “Pure Black and White”
 Come to class
 Do the PAL exercises
 Answer the Quizdom questions
 Lab once a week
 Three tests and final
WebAssign
Homework will be entered and graded online
At webassign.com
Click on student login
Username is your first and last name together
(e.g. “johnsmith”)
Institution is “augustana”
Password is same as last semester
Augustana ID number if new to class
After login, click on the current assignment and
complete it
WARNING: Can only submit it three times
Homework
Homework will generally be from book
Will be posted on webpage if you want to look at
them without a computer
WebAssign will randomize numbers
Available at noon M,W,F
Due at midnight Tue, Thu, Sun
Cannot turn homework in late or make up
Can drop lowest three
Each homework worth same amount (100
points)
10% of grade
Can drop (or miss) three
No make-ups or grade changes
PAL
What is PAL?
Physics Active Learning
Each class you will get a PAL
worksheet
Also will answer questions with
Quizdom remotes
Worth 15% of your grade
Need to come to class
Can drop (or skip) three PAL’s
Grading on Tests and PALs
1. Written answers must be in complete
sentences
2. Numbers must have units
3. Answers must reasonable
• If not reasonable, explain why
4. All work must be neat and easily
readable
Thermodynamics
What is thermodynamics?
Thermo

Dynamics

Thermodynamics is the study of
thermal and mechanical energy
How do you transform one into the other?
Where Does Thermodynamics
Come From?
Back in the early 1800’s people figured
out that you can transform thermal into
mechanical energy

A heat engine
Problem:
Need to understand what is going on in
the engine
Temperature
How does temperature manifest itself?

e.g., the height of a column of fluid

We still don’t know what temperature is
Thermal Equilibrium

A thermoscope
Now put the thermoscope in a cup of water

They are not transferring heat
They are at the same temperature
Two bodies at different temperatures placed
together will exchange heat until they are in
thermal equilibrium (and thus at the same
temperature)
Zeroth Law of Thermodynamics

or
if a thermoscope placed near one and then the
other reads the same
Zeroth Law of Thermodynamics
If two objects are each in thermal equilibrium with
a third object then they are also in thermal
equilibrium with each other
Thermometers
In order for a thermoscope to be a
thermometer it needs to be calibrated
Example: the Celsius scale

Put it in ice and mark the height of the column as 0

Fill in the numbers 1-99 (in even intervals) in
between

 Only tells you temperature relative to the freezing point
of water
Types of Thermometers
 Glass tube
 Physics: Increase of
length with increasing
temperature
 Pros:
 Cons:
 Resistance
 Physics: Electrical
resistance increases with
increasing temperature
 Pros:
 Dial
 Physics: Increased bending
of bi-metal strip with
temperature
 Pros:
 Cons:
 Radiation
 Physics: Change in type
and amount of radiation
emitted with temperature
 Pros:
 Cons:
 Cons:
Temperature Scales
Gabriel Daniel Fahrenheit invented the
mercury thermometer in 1714

Anders Celsius introduced his scale is 1742

William Thomson, Lord Kelvin, determined
from theory that minus 273.15 degrees
Celsius is the coldest it can get
The Kelvin Scale
In science we normally use the Kelvin scale

Tells you temperature relative to absolute zero,
the coldest anything can get

No negative numbers

TC = TK -273.15
TF = 9/5 TC +32
A temperature change of 5 Celsius degrees is
equal to a temperature change of 9 Fahrenheit
degrees
Thermal Expansion
Heating an object causes it to expand

Why?

The degree of expansion depends on the
change in temperature and the coefficient of
expansion
We can measure temperature and look up
coefficient of expansion
Linear Expansion
The degree to which the length of an object
changes is given by:
DL = L a DT
Where a is the coefficient of linear expansion
This applies to all dimensions of a solid
length, width and height
Change in length is proportional to length
and temperature change
If the linear dimensions of a solid change then
the volume must change:
DV = V b DT
 Where b=3a
Thermal Expansion and
Thermometers

Consider two strips of metal with different
coefficients of linear expansion attached
together (bimetal strip)

This principle is used in dial thermometers
and thermostats
Next Time
Read: 13.4, 14.3-14.4, 14.6-14.8
Homework: CH 13, P 9, 10, 11, CH 14: 9,
33
Due midnight before class
Note that you might have to look up
values in the textbook
Watch units!