Physics Website


Chair, Associate Professor TIKU MAJUMDER

Professors: K. JONES*, WOOTTERS. Associate Professors: AALBERTS*, S. BOLTON, MAJUMDER, STRAIT. Assistant Professors: TUCKER-SMITH, WHITAKER*. Visiting Professor: CRAMPTONž. Lecturer: BABCOCK. Visiting Lecturer: WALTON. Laboratory Supervisor: FORKEY. Laboratory Instructor: WEBSTER.

What is light? How does a transistor work? What is a black hole? Why are metals shiny? What is wave/particle duality? There are people for whom questions like these are of more than passing interest; some of them become Physics or Astrophysics 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. A Physics or Astrophysics major serves as preparation for further work in physics, astrophysics, applied physics, other sciences, engineering, medical research, science teaching and writing, and other careers involving insight into the fundamental principles of nature.


The Physics Department, in cooperation with the Astronomy Department, offers a major in astrophysics consisting of (at least): 6 or 7 courses in Physics, 3 or 4 in Astronomy, and 1 in Mathematics. The core sequence of the Astrophysics major is the same as the Physics major described below (except that Physics 302, although strongly recommended, is not required). Students intending to pursue graduate study in astrophysics will need to take upper-level physics electives beyond the basic requirements for the major. Honors work in Astrophysics may be in either physics or astronomy. Students majoring in Astrophysics are expected to consult early and often with faculty from both departments in determining their course selections. The detailed description of the Astrophysics major is given under "Astronomy," along with a description of the Astronomy major also offered by that department (see page 16).


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 or 106). Students are encouraged to take Physics 210 as early as possible. Physics 210 is cross listed as Mathematics 210 for the benefit of those students who wish to have the course listed with a MATH prefix.

Advanced Placement

Students with unusually strong backgrounds in calculus and physics may place out of Physics 141 and either: 1) begin with the special seminar course Physics 151 in the fall (typically followed by Physics 210 in the spring), or 2) begin with Physics 142 in the spring (possibly along with Physics 210). Students may take either 151 or 142 but not both. On rare occasions a student with an exceptional background will be offered the option of enrolling in Physics 201.

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. Students who place out of both Physics 141 and Physics 142 and begin their studies in Physics 201 are required to take a total of nine courses.

Required Physics Sequence Courses

  1. Physics 141 Particles and Waves-Enriched
    or Physics 131 Particles and Waves
  2. Physics 142 Foundations of Modern Physics
    or Physics 151 Seminar in Modern Physics
  3. Physics 201 Electricity and Magnetism
  4. Physics 202 Waves and Optics
  5. Physics 210 Mathematical Methods for Scientists
  6. Physics 301 Quantum Physics
  7. Physics 302 Statistical Physics

Required Mathematics Course

  1. Mathematics 105 Multivariable Calculus or Mathematics 106 Multivariable Calculus

Students entering with Advanced Placement in mathematics may obtain credit toward the major for the equivalent Mathematics 105 or 106 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.


1) Mathematics 104 may be counted if taken at Williams

2) Mathematics 209 may substitute for Physics 210.

3) Astronomy 111 may count in place of Physics 141 if a student places out of 141 (see "advanced placement" above).

4) An additional Astronomy or Astrophysics course above the introductory level that is acceptable for the astrophysics major may be counted.

5) 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.

6) Honors work is in addition to completion of the basic major so Physics 493 and 494 do not count towards the ten courses in the major.

Preparation for Advanced Study

Students who may wish to do graduate work in physics, astrophysics, 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:

  1. Physics 402T Applications of Quantum Mechanics
  2. Physics 405T Electromagnetic Theory
  3. Physics 411T Classical Mechanics


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.

The department also offers one semester courses designed for non-majors. This year there are three such offerings: Physics 100, Physics 109, and Physics/Religion 342.

Courses numbered 450 through 459 are independent reading courses in advanced topics. Students will read a textbook or other material and work problems. Once a week the students and the instructor will meet for discussion and student presentations. Due to the initiative and independence required, interested students should consult with the instructor before registering for one of these courses. Enrollments will be limited, usually to 4 or fewer.