Course Information

Physics 120 -- Heat, Waves, and Light – Winter 2026

Instructors 

Mark Shroyer       Office: D109 SMC, ext. 7847, mshroyer@knox.edu

Tom Moses          Office: D116 SMC, ext. 7341, tmoses@knox.edu


 

Class Meetings 
Section 1 MTuThF 2nd period, D108 SMC (Shroyer)
Section 2 MTuThF 6th period, D108 SMC (Moses)

 

Text  Douglas C. Giancoli, Physics for Scientists and Engineers, 4th ed. (Prentice-Hall, Englewood Cliffs, NJ, 2008).

Course Website: http://course.knox.edu/physics120/

Direct connection to the homework site

https://physics.knox.edu/OnlineHW/phys120/winter

Homework  Homework problems sets, adapted from Giancoli’s text, will be available on-line at the course website. The online homework software displays the problems, with your own individually-customized random numerical parameters, provides hints if requested, and gives instant feedback by telling you when your answer is correct. For full credit, homework sets are due by 9:00 a.m. on the due day.  Homework problems can be completed up to one week after the due date for half-credit.

Working out the homework problems is probably the most important single aspect of the course for learning physics.  It is in the effort to understand specific problems that you make real progress in understanding.  You are encouraged to work together in groups on the homework problems; you may consult other books or people, and especially, you may feel free to consult me if you have trouble with a problem.

Honor Code, Internet Solutions, and AI (Artificial Intelligence Software)

You are expected to abide by the Knox College Honor Code.

You may work together in groups to discuss and solve problems related to the homework problems and lab reports.  In writing up your lab reports and calculating final solutions on the problem sets, each person must do his or her own work. The use of online homework aids or solution manuals is prohibited. Duplicate lab reports are not allowed, even by lab partners.  You may share data with your lab partner only if both of you were present in the lab together collecting the data. You many not share any text written as part of your lab report.

The use of online homework aids and solution manuals is prohibited.

You additionally are not allowed to use AI (for example, chatGPT) to seek solutions to point bearing work (homework problems, lab reports, quizzes, and exams).  Doing so is a violation of the Honor Code as you are presenting work that is not yours for credit.

Additionally, while AI might effectively solve some of the problems we’ll encounter, relying on it deprives you of the opportunity to learn the underlying principles of physics. The purpose of problem-solving is to help you learn the process, which often involves working through challenges, making mistakes and learning from them. Therefore, solutions provided by AI or other internet sources are not appropriate to submit or use.

However, this does not mean that you can never use AI in relation to the class. You may use AI to clarify content and assist with understanding (but not for homework problems, lab reports, quizzes, and exams). Always keep in mind, though, that AI frequently makes errors in physics, particularly with mathematics, so use it cautiously and critically. It is a poor substitute for speaking to your professor!

As always, if you are unsure if something is allowed, please ask!

Attendance and Make-Up Policy
Class attendance is required, and unexcused absences may trigger deductions from the course average.  Up to 3 absences can be excused, by reporting the absence and the reason for it before the beginning of class.  Only students with excused absences are allowed to make up a missed quiz or exam.

Lab instructor Nathalie Haurberg, nhaurber@knox.edu.

Labs  Laboratory sessions will be held every Wednesday in D105 (across the hall from the classroom). You will have a pre-lab activity due when you arrive to the lab session each week. 

Exams  There will be two mid-term exams and a comprehensive final exam, as well as a number of small quizzes.

Midterm exam 1

Friday, Jan. 30

Midterm exam 2

Tuesday, Feb. 24

Final

 

During the normal scheduled Period 2 and Period 6 times (TBA)

Grade Weighting

Homework

15%

Labs

15%

Quizzes

10%

2 Midterm exams

35%

Final exam

25%

 Late Policy  Homework completed within a week after the due date counts half credit.  As usual in science courses, it is absolutely vital not to fall behind in the homework.  Labs turned in late lose 10% per working day.

Physics 120 - Approximate Schedule

Week

 

Topic                                                             

Reading

1

 

Temperature, thermal expansion, ideal gas law

Ch 17, 18

2

 

Kinetic theory, heat

Ch 18, 19

3

 

First law of thermodynamics and applications

Ch 19, 20

4

 

Second law of thermodynamics and applications

Ch 20

 

Exam 1

 

5

 

Simple harmonic oscillation

Ch 14, 15

6

 

Wave motion, sound

Ch 15, 16

7

 

Light reflection and refraction

Ch 32, 33

Exam 2

8
 Lenses and optical instruments Ch 34

9

 

Wave nature of light, interference

Ch 34, 35

10

 

Diffraction of light, polarization

Ch 35

            Final Exam

Course Description:


The middle course in our introductory physics sequence is devoted in roughly equal thirds to heat, waves, and light.  The first section explores thermodynamics and kinetic theory, with the goal of understanding the microworld of atoms and molecules.  We’ll be able to estimate the size of atoms, the speed of molecules in the air, the distance particles in a gas travel between collisions, and the time-scale of heat and molecular diffusion.  Thermodynamics connects the microworld and the world of everyday macroscopic phenomena, with consequences ranging from the limitations on the best possible engine to the greenhouse warming of the planet and the ultimate fate of the universe.


We take up wave phenomena next, beginning with an exploration of simple harmonic motion.  Oscillatory motion is ubiquitous in the microworld of atoms and molecules as well as in macroscopic structures like machines, planets, and stars.  Indeed, at ordinary temperatures everything is vibrating.  Vibrations cause waves, and wave phenomena are therefore also everpresent. We’ll study two examples in some depth: sound and light.


We’ll devote special attention to light or electromagnetic waves, since it is through light that we obtain much of our information about the world.  Because of the great range of wavelengths involved (from 102 m for AM radio waves to 10-12 m for gamma rays), we’ll see that different mathematical models (ray model vs. wave model) will be appropriate to describe and predict phenomena depending on the wavelength.  This is one of the first (and certainly not the last) occasion where we’ll have the opportunity to glimpse the characteristic progress of science, advancing via a succession of models of nature.


Some advice for the student: This course probably has more physical ideas than any other course in the introductory sequence (and maybe any other course in our curriculum).  Reading the textbook and thinking about the physical picture is consequently more important even than usual.  Although the math level is confined to algebra, geometry, and elementary trig, you can expect to build problem-solving skill translating a wide variety of physical situations into mathematical form.  As is standard in science and particularly physics courses, a regular and faithful work ethic is essential to your success (that means some study, reading, and problem solving every day).