Chair, Professor KEVIN M. JONES

Professors: CRAMPTON*, JONES, WOOTTERS. Associate Professor: STRAIT. Assistant Professors: AALBERTS, S. BOLTON, MAJUMDER*. Visiting Assistant Professor: KRAUSE. Lecturer: BABCOCK. Laboratory Supervisor: FORKEY.

What is light? How does a transistor work? What is a proton made of? Why are metals shiny? Why is glass transparent? There are people for whom questions like these are of more than passing interest; some of them become physics majors. A physics student experiments with the phenomena by which the physical world is known and explores the mathematical techniques and theories that make sense of it. The major serves as preparation for further work in pure or applied physics, other sciences, engineering, medical research, science teaching and writing, and other careers involving insight into the fundamental principles of nature.

In addition to the physics major, the Physics Department also offers a major in astrophysics, in cooperation with the Astronomy Department. That major is described elsewhere in this Catalog.


Introductory courses

Students considering a major in physics should take both physics and mathematics as first-year students. A student normally begins with either Physics 131 or Physics 141:

1. Physics 131 Particles and Waves. This is designed as a first course in physics. It is suitable for students who either have not had physics before or have had some physics but are not comfortable solving "word problems" that require calculus.

2. Physics 141 Particles and Waves-Enriched. Students in this course should have solid backgrounds in science and calculus, either from high school or college, including at least a year of high school physics.

The Department of Mathematics will place students in the appropriate introductory calculus course. The physics major sequence courses all make use of calculus at increasingly sophisticated levels. Therefore, students considering a physics major should continue their mathematical preparation without interruption through the introductory calculus sequence (Mathematics 103, 104, and 105). Students are encouraged to take Mathematics 210 as early as possible.

Advanced Placement

Students with unusually strong backgrounds in calculus and physics may place out of Physics 141 and are encouraged to elect either Physics 200F or Astronomy 111 instead. On rare occasions a student with an exceptional background will be offered the option of enrolling in Physics 201 prior to taking Physics 142. In either case, Physics 142 should be elected in the spring.

Placement is based on AP scores, consultation with the department, and results of a placement exam administered during First Days. The exam can also be taken later in the year by arrangement with the department chair. The exam covers classical mechanics, basic wave phenomena, and includes some use of calculus techniques.

Requirements for the major

A total of ten courses in physics and mathematics are required to complete the physics major.

Required Physics Sequence Courses

Physics 141 Particles and Waves-Enriched
or Physics 131 Particles and Waves

Physics 142 Physics Today

Physics 201 Electricity and Magnetism

Physics 202 Waves and Optics

Physics 301 Introductory Quantum Physics

Physics 400 Thermal and Statistical Physics

Required Mathematics Courses

Mathematics 105 Multivariable Calculus

Mathematics 210 Differential Equations and Vector Calculus

Students entering with Advanced Placement in mathematics may obtain credit toward the major for the equivalent Mathematics 105 taken elsewhere.


At least two more physics or other approved courses must be taken, bringing the total number of courses for the major to ten. The following provisions apply to these elective courses:

1. Mathematics 104 may be counted if taken at Williams.

2. Astronomy 111 may count in place of Physics 141 if a student places out of 141 (see below).

3. An additional astronomy or astrophysics course above the introductory level that is acceptable for the astrophysics major may be counted.

4. Two approved Division III courses above the introductory level may be substituted for one physics course. Approval is on an individual basis at the discretion of the department chair.

Preparation for Advanced Study

Students who may wish to do graduate work in physics or engineering should elect courses in both physics and mathematics beyond the minimum major requirements. The first year graduate school curriculum in physics usually includes courses in quantum mechanics, electromagnetic theory, and classical mechanics that presuppose intermediate level study of these subjects as an undergraduate. Therefore, students planning graduate work in physics should elect all of the following courses:

Physics 402T Applications of Quantum Mechanics

Physics 405T Electromagnetic Theory

Physics 411T Classical Mechanics

In addition, students interested in experimental physics or engineering will find Physics 200 Electronics useful.


Both majors and non-majors are encouraged to consult with the department chair or course instructors about course selections or other matters.


The degree with Honors in Physics will be awarded on the basis of a senior thesis presenting the results of a substantial experimental or theoretical investigation carried out under the direction of a faculty member in the department. There is no rigid grade point average required for admission to the program or for the awarding of the degree with honors, but it is normally expected that honors students will maintain at least a B average in physics and mathematics. Students will normally apply for admission to the program early in the spring of their junior year and during senior year these students will normally elect Physics 493, W031, and 494 in addition to the usual requirements for the major. At the end of Winter Study, the department will decide whether the student will be admitted to honors candidacy. Both a written thesis and a colloquium presentation of the results are required. The degree with honors will be awarded to those who meet these requirements with distinction. The degree with highest honors will be awarded to those who fulfill them with unusually high distinction.

Honors candidates will also be required to participate in departmental colloquium talks.


Many students want to take a self-contained and rigorous full-year survey of physics. For such students, the most appropriate sequence will be either Physics 131 or Physics 141 followed by Physics 132, depending on the student's background in science and mathematics (see Introductory Courses above). Either of these sequences satisfies the physics requirement for medical school.

Non-majors are welcome to enroll in Physics 200F Electronics. The department also offers less quantitative or more specialized courses for non-majors. This year there are two such offerings: Physics 100 and Physics 109.