College Bulletin - Course Catalog 
    Jul 25, 2021  
College Bulletin - Course Catalog

Physics and Astronomy


MICHAEL R. BROWN, Morris L. Clothier Professor of Physics
DAVID H. COHEN, Professor of Astronomy and Chair
CATHERINE H. CROUCH, Professor of Physics
AMY LISA GRAVES, Walter Kemp Professor of Physics in the Natural Sciences
ERIC L. N. JENSEN, Professor of Astronomy3
TRISTAN SMITH, Associate Professor of Physics
CACEY STEVENS BESTER, Assistant Professor of Physics
HILLARY L. SMITH, Assistant Professor of Physics2
BENJAMIN D. GELLER, Assistant Professor of Physics (Part-time)
KRISTINE LUI, Visiting Assistant Professor of Physics
JESUS RIVERA, Visiting Assistant Professor of Astronomy
MARY ANN KLASSEN, Senior Laboratory Lecturer
PAUL JACOBS, Instrumentation Technician
STEVEN PALMER, Machine Shop Supervisor
CAROLYN WARFEL, Administrative Coordinator

1 Absent on leave, fall 2020
2 Absent on leave, spring 2021
3 Absent on leave, 2020-2021

The Physics and Astronomy Department teaches the concepts and methods that lead to an understanding of the fundamental laws governing the physical universe.

Emphasis is placed on quantitative, analytical reasoning, as distinct from the mere acquisition of facts. Particular importance is also attached to laboratory work because physics and astronomy are primarily experimental and observational sciences.

With the awareness that involvement in research is a major component in the education of scientists, the department offers a number of opportunities for students to participate in original research projects, conducted by members of the faculty, on campus.

Several research laboratories are maintained by the department to support faculty interests in the areas of plasma physics, nanophysics, computer simulation, liquid crystals, materials physics, granular media, and observational and theoretical astrophysics and cosmology.

The department operates the Peter van de Kamp Observatory for student and faculty research, plus several small telescopes for instructional use. The observatory is equipped with a 61-cm reflecting telescope, a high-resolution spectrograph, and a CCD camera for imaging and photometry. A monthly visitors’ night at the observatory is announced on the department website. 

Three calculus-based introductory sequences are offered. PHYS 003 and 004 cover both classical and modern physics and are an appropriate introductory physics sequence for those students majoring in engineering and some chemistry majors. A parallel sequence, PHYS 003L and 004L, has a focus on the life sciences and is an appropriate sequence for students interested in biochemistry, and biology. PHYS 007 and 008, on the other hand, which are normally preceded by PHYS 005, are at a more advanced level. They are aimed towards students planning to do further work in physics or astronomy and are also appropriate for engineering and chemistry majors. The sequence of courses from PHYS 005 to PHYS 018 is designed to provide a comprehensive introduction to the major topics and mathematical tools of physics.

Additional information is available at

The Academic Program

In order to receive a degree from Swarthmore as a physics, astrophysics, or astronomy major, a student must have taken and satisfactorily passed one of the programs described below. In the Physics and Astronomy Department, the seminar is the standard format for most junior and senior level work. All prospective majors and minors in the department should realize this when planning programs. The seminars are open to all students, both honors and course majors and minors.

NOTE: Due to the pandemic, we have temporarily altered our major requirements for students graduating in 2021 or 2022.

First Course Recommendations

PHYS 005. Spacetime and Quanta  introduces and explores in some depth special relativity and quantum mechanics - two key theories of modern physics and astronomy. This course is intended as an entry point to the major track for both physics and astronomy, regardless of the degree of high school physics and math preparation a first-year student has had.

PHYS 003. General Physics I : Motion, Forces, and Energy is calculus-based and has a weekly lab component and is the entry point for a two-course physics sequence required of engineering majors. Although most prospective majors start in Physics 005, if after taking Physics 003 you wish to consider a major in our department, please speak to your instructor or to the department chair and we will be glad to discuss pathways for doing so.

PHYS 003L. General Physics I: Motion, Forces, and Energy with Biological and Medical Applications  is calculus-based and has a weekly lab and is the entry point for a two-course physics sequence intended for biology, pre-med, and chemistry students. It covers the same basic physical ideas as Physics 003 but applies those ideas to systems of interest to those studying biology, medicine, or chemistry.

Note that in general, majors cannot replace Physics 005 (or most other major requirements) with AP credit or college courses taken during high school. However, students who need to take Physics 003 or Physics 003L to meet other departments’ requirements can get Swarthmore credit for work done prior to college if they scored a 5 on the physics AP exam (or a 6 to 7 on the IB exam) *and* they achieve a good score on the department’s placement test, which is given the week before classes start in the fall (but in certain cases may be taken at other times throughout the year).

Core Programs

In the spirit of a liberal arts education, we note that one need not be considering a career in physical science to find a physics, astrophysics, or astronomy major beneficial and stimulating. The physics core curriculum and the astronomy core curriculum listed below both provide excellent training in quantitative reasoning and independent problem solving, skills that are applicable in a wide variety of arenas (law, medicine, science journalism, public policy). Since all of the fundamental areas are covered, the physics core curriculum is also excellent preparation for a career in a scientific field related to physics, such as engineering or teaching physics in high school. The astronomy curriculum is excellent preparation for teaching astronomy in high school, or working as a telescope operator or data analyst. These curricula are ideal for double majors.

While the physics core curriculum is adequate preparation for graduate study in physics, students considering graduate school are encouraged to take additional seminars, especially those listed below under “Enhanced Programs.” Most graduate programs in astronomy expect somewhat more physics preparation than the minimum listed in the astronomy curriculum. Those considering graduate school in astronomy are encouraged to take as much additional physics as scheduling permits, and ideally, to choose the astrophysics major listed below under “Enhanced Programs .”

* Note: The Mathematics and Statistics Department offers many sets of courses covering similar material at different levels of sophistication. In each case noted, the most elementary version from each set has been listed. Students should always take the most advanced version for which they qualify, e.g. MATH 034 or 035 rather than MATH 033, if possible.

Physics Core Curriculum

  • PHYS 005
  • PHYS 007, 008, 013, 015, 017, 018
  • PHYS 111, 112, 113, 114
  • PHYS 063, 081, 082
  • MATH* 015, 025, 027, 033

Astronomy Core Curriculum

  • PHYS 005
  • PHYS 007, 008, 013, 015, ASTR 014 or 016, ASTR 061
  • Four Astronomy seminars (can include upper-level astronomy courses at Haverford); ASTR 014 or 016 may be substituted for one seminar
  • MATH* 015, 025, 027, 033


Under some circumstances, PHYS 003, 004 can be substituted for PHYS 007, 008.

†Students who have taken ENGR 072 may substitute PHYS 083 instead of PHYS 081, 082.

Enhanced Programs

These programs provide strong preparation for graduate study in physics, astrophysics, or astronomy.

Physics Enhanced Curriculum

In addition to the physics core requirements listed above, any two advanced seminars

Astrophysics Curriculum

  • PHYS 005
  • PHYS 007, 008, 013, 015, 017, 018, ASTR 014 or 016
  • Two Astronomy Seminars
  • PHYS 111, 112, 113, 114
  • MATH* 015, 025, 027, 033

Other Requirements

Seniors not in the Honors Program must complete a comprehensive exercise, which is intended both to encourage review and synthesis and to allow students to demonstrate mastery of fundamentals studied during all four years. In addition, all students must satisfy the College distribution requirements and the 20-course rule (except for special majors such as astrophysics or chemical physics, for whom the 20-course rule is waived).

Modifications for students in the class of 2021 and 2022, due to the pandemic: 

For the class of 2021, physics and astrophysics majors may take 3 of the 4 core physics seminars and instead of taking the fourth, substitute an elective seminar, two semesters of journal club, or a directed reading or research for credit (totaling 1.0 credits). Physics majors may also choose to take just one semester of advanced lab rather than two. 

For the class of 2022, physics and astrophysics majors must take Phys 113 but may take just 2 of the 3 other core physics seminars and instead of taking the third, substitute an elective seminar, two semesters of journal club (totaling 1.0 credits).

For astronomy majors in either class, rather than taking 4 astronomy seminars, a student may take 3 and substitute a physics seminar, an advanced astronomy class at another Tri-Co school, or two semesters of journal club (totaling 1.0 credits). 

In the detailed descriptions below, we assume the standard, non-pandemic requirements. Adjustments can be made to them according to the policies listed above. 

Course Major

A student applying to become either a physics major in the core program or an astronomy major should have completed or be completing PHYS 005 and either PHYS 004 or PHYS 008. Otherwise it will be impossible to fulfill all program requirements. To be accepted as a major, the applicant must have received grades of C+ or better in Physics, Astronomy, and Math courses.

A student applying to become a physics major in either the enhanced program in course or the Honors Program should have completed or be completing courses through PHYS 008, PHYS 013, PHYS 015, PHYS 017, PHYS 018. In addition, to be accepted into the course major, these courses must be completed with an average grade of C+ or better. To be accepted into the Honors Program with a physics major, the average grade should be a B or better. Grades in math courses should be at a similar level.

A student applying to become an astrophysics major in course or in honors should have completed or be completing PHYS 008, PHYS 013, PHYS 015, PHYS 017, PHYS 018, and ASTR 016 or ASTR 014.  In addition, applicants for the Honors Program in either astrophysics or astronomy must normally have an average grade in physics and astronomy courses of B or better.

Since almost all advanced work in physics and astronomy at Swarthmore is taught in seminars where the student participants share the pedagogical responsibility, an additional consideration in accepting (retaining) majors is the presumed (demonstrated) ability of the students not only to benefit from this mode of instruction but also to contribute positively to the seminars. Grades in prior courses are the best criteria in admitting majors, since they tend to indicate reliably whether or not the student can handle advanced work at Swarthmore levels without being overwhelmed. However, constructive participation in classes and laboratories is also considered.

Program for the Last Two Years

The following one-credit physics seminars are offered on a regular basis (regardless of faculty leaves):

Prerequisites: PHYS 005, 007, 008, 013, 015, 017, and 018

Course Minor

The Physics and Astronomy Department offers two types of course minor, one in physics and one in astronomy.

Physics Minor Curriculum

  • PHYS 005
  • PHYS 007
  • PHYS 008
  • PHYS 013
  • PHYS 015
  • PHYS 017
  • PHYS 018
  • PHYS 111 and 113†
  • MATH* 015, 025, 033

Under some circumstances, PHYS 003 and/or PHYS 004 may be substituted for PHYS 007 and/or PHYS 008.

We prefer that minors have two advanced seminars, one in “classical” and one in “quantum” physics. PHYS 111 is a prerequisite for future seminars and fulfills the “classical” requirement. While we recommend PHYS 113 as the second advanced seminar, a different seminar may be substituted upon consultation with the Chair.

Astronomy Minor Curriculum

  • PHYS 005
  • PHYS 007 or PHYS 003
  • PHYS 008 or PHYS 004
  • ASTR 014 or 016
  • One Astronomy seminar numbered 100 or above
  • One semester of ASTR 061 (0.5 credits)
  • MATH* 015, 025, 033

* Note: The Mathematics and Statistics Department offers many sets of courses covering similar material at different levels of sophistication. In each case noted, the most elementary version from each set has been listed. Students should always take the most advanced version for which they qualify.

Honors Major

Honors majors must meet the requirements for the major as described above, and select three of the following preparations, plus their prerequisites.

Honors Major Programs

Physics: Electrodynamics (PHYS 112), Quantum Theory (PHYS 113), Statistical Physics (PHYS 114), Honors Thesis (PHYS/ASTR 180)

Astrophysics: Any of the seminars from the astronomy program, plus: Electrodynamics (PHYS 112), Quantum Theory (PHYS 113), Statistical Physics (PHYS 114), Honors Thesis (PHYS/ASTR 180)

Note: must include at least one seminar each from astronomy and physics.

Astronomy: Research Techniques in Observational Astronomy (ASTR 121), Stars and Stellar Structure (ASTR 123), The Interstellar Medium (ASTR 126), Honors Thesis (ASTR 180).

Note: In some cases, elective seminars may be used as honors preparations.

Note: External examination for honors major programs includes two or three 3-hour written examinations on the chosen preparations, plus two or three 30-45 minute oral examinations on the chosen preparations, plus one 45-60 minute oral examination on the honors thesis (for thesis writers).

Honors Minor

Physics: One of the following seminars PHYS 112, PHYS 113, PHYS 114

Astrophysics: One of the following seminars PHYS 112, PHYS 113, PHYS 114, ASTR 121, ASTR 123, ASTR 126

Astronomy: One of the following seminars (ASTR 121, ASTR 123, ASTR 126)

Note: External examination for honors minor programs includes one three-hour written examination on the chosen preparations, plus one 30-45 minute oral examination on the chosen preparations.

Research Opportunities

Advanced Laboratory Program

In the junior and senior years, all physics majors must take PHYS 081 and PHYS 082. Students enrolled in PHYS 081 and PHYS 082 must arrange their programs so that they can schedule an afternoon for the laboratory each week free of conflicts with other classes, typically Friday afternoon. Enrollment in each of these laboratories will appear on the student’s transcript with a letter grade for 0.5 credit for each semester. PHYS 081, 082 together count as a “writing course” for collegiate graduation requirements. Students with credit for ENGR 072 may replace PHYS 081, 082 with PHYS 083, which is an advanced lab experience without an electronics component.

Independent Work

Physics, astrophysics, and astronomy majors are encouraged to undertake independent research projects, especially in the senior year, either in conjunction with one of the senior seminars, or as a special project for separate credit (PHYS/ASTR 094). Members of the physics or astronomy faculty are willing to suggest possible projects and to supervise one of these if the student chooses to pursue it. Students completing work under PHYS/ASTR 094 are required to submit final written and oral reports of their work to the department. In preparation for independent experimental work, prospective physics majors are strongly urged to take the required 0.5 credit course PHYS 063, Procedures in Experimental Physics, during their fall semester of their sophomore year, which will qualify them to work in the departmental shops. There are usually many opportunities for students to receive financial support to work with faculty members on research projects during the summer.


Students may do a theoretical or experimental research thesis representing the results of independent work done under the supervision of a faculty member. This thesis will usually cover work begun in the summer after the junior year and completed during the senior year. A thesis is optional for all students in the Honors Program.

Off-Campus Study

With proper planning, study away from Swarthmore for one or two semesters is possible while majoring in physics, astronomy, or astrophysics. However, the many prerequisites in the Physics and Astronomy Department make careful planning for study abroad a necessity. Spring of junior year is often the easiest time to make this work. The important point is to begin planning at an early stage. This allows students (1) to make sure courses not available abroad are taken at Swarthmore, and (2) to find out well in advance what physics and astronomy courses are available in the various study abroad programs. While it is completely feasible to complete a physics major without taking physics abroad (e.g. if one is studying in a non-English-speaking country), students should note when planning their programs that PHYS 111 must be taken before PHYS 113 or PHYS 114.

Teacher Certification

We offer teacher certification in physics through a program approved by the state of Pennsylvania. For further information about the relevant set of requirements, contact the Educational Studies Department chair, the Physics Department chair, or visit the Educational Studies Department website at

Astronomy Seminars

Students interested in upper-level work in astronomy are encouraged to also consult Haverford’s course schedule, since the two astronomy programs actively work to offer complementary topics.