College Bulletin 2022-2023 
    Jun 20, 2024  
College Bulletin 2022-2023 [ARCHIVED CATALOG]

Physics and Astronomy



MICHAEL R. BROWN, Morris L. Clothier Professor of Physics, and Chair
DAVID H. COHEN, Professor of Astronomy
CATHERINE H. CROUCH, Professor of Physics3
ERIC L. N. JENSEN, Professor of Astronomy
TRISTAN SMITH, Associate Professor of Physics3
CACEY STEVENS BESTER, Assistant Professor of Physics3
HILLARY L. SMITH, Assistant Professor of Physics
BENJAMIN D. GELLER, Associate Professor of Physics
STEPHEN HACKLER, Visiting Assistant Professor of Physics
JEFFREY HYDE, Visiting Assistant Professor of Physics
WING-HO KO, Visiting Assistant Professor of Physics
JESUS RIVERA, Visiting Assistant Professor of Astronomy
MARY ANN KLASSEN, Senior Laboratory Lecturer
KRISTEN RECINE, Laboratory Lecturer
PAUL JACOBS, Instrumentation Technician
STEVEN PALMER, Machine Shop Supervisor
CAROLYN WARFEL, Administrative Coordinator

1 Absent on leave, fall 2022
2 Absent on leave, spring 2023
3 Absent on leave, 2022-2023

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 experimental and observational sciences.

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, 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. 

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.

First Course Recommendations

PHYS 005. The World of Particles and Waves  introduces and explores in some depth optics 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. It also welcomes non-majors interested in learning this material at a moderately mathematical level. For non-majors interested in a less mathematical course, Astronomy 1 is recommended.

In general, majors cannot replace Physics 005 (or most other major requirements) with AP credit or college courses taken during high school.

PHYS 003. General Physics I : Motion, Forces, and Energy is calculus-based and has a weekly lab. It 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.

Students can get Swarthmore credit for Physics 3 from work done prior to college in either of two ways: 
1) if a student scored a 5 on the physics AP exam (or a 6 to 7 on the IB exam) *and* they achieve the necessary score on the department’s placement test. 
2) if a student achieves the necessary score on the department’s longer, different test for credit. 
The test for placement is available online; the test for credit must be taken in person on paper. The placement and credit tests are given the week before classes start in the fall. Contact the department before winter break to request a test just before the start of the spring semester.

Core Programs

In the spirit of a liberal arts education, we believe that a physics, astrophysics, or astronomy major can be beneficial and stimulating to students with a wide range of long-term interests and goals. 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 at the high school level, or working as a telescope operator or data analyst. Many students in our department do 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. 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.

Physics Major Requirements

For students pursuing graduate study, all four of PHYS 107 (or PHYS 113), PHYS 111, PHYS 112, and PHYS 114 will make the student’s application particularly strong.

Astronomy Major Requirements

Astrophysics Major Requirements

In addition to the Physics core requirements listed above:

  • ASTR 014   or ASTR 016  
  • ​Two Astronomy 100-level offerings (one of which can also be the fourth 100-level Phys or Astr for the Physics requirements)

Not required for Astrophysics major: PHYS 063, PHYS 081, and PHYS 082


* Half-credit course
ENGR 006 and PHYS 003 together may be substituted for PHYS 007. In some cases, with permission from the department, PHYS 003 alone may be substituted for PHYS 007.
§ In some cases, with permission from the department, PHYS 004 and a placement test may be substituted for PHYS 008 
† PHYS 083 is an alternative to PHYS 081 and 082 for students to meet the advanced lab requirement if they will also take ENGR 072 

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).

Advanced Laboratory Program

In the junior and senior years, all physics majors must take PHYS 081 and PHYS 082. 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.

Applying for Majors

A student applying to become either a course major in physics or astronomy should have completed or be completing PHYS 005  and either PHYS 004 , PHYS 006  (or PHYS 013  and PHYS 015 ), or PHYS 008 . 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 an honors physics major should normally have completed or be completing PHYS 008 . 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  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.

Course Minor

Physics Minor Requirements

PHYS 005 PHYS 006  or both PHYS 013 * and PHYS 015 *;
PHYS 007 #; PHYS 008 §PHYS 107  and PHYS 064  or both PHYS 017 and PHYS 018; 
One more 100-level physics offering, normally PHYS 111  or PHYS 112 , but occasionally PHYS 114  or an elective may be approved by the department;  
MATH 015 *; MATH 025 MATH 027  or MATH 028 MATH 033  or MATH 034  

Astronomy Minor Requirements

PHYS 005  and PHYS 006 ; or PHYS 005 PHYS 013 * and PHYS 015 *,
PHYS 007 # or PHYS 003 PHYS 008  or PHYS 004 ,
ASTR 014  or ASTR 016 ,
One Astronomy 100-level offering,
One semester of ASTR 061 *,
MATH 015 *, MATH 025 , MATH 033  or MATH 034  

Astrophysics Minor Requirements

PHYS 005 PHYS 006  or both PHYS 013 * and PHYS 015 *;
PHYS 007 #;  PHYS 008 §
ASTR 014  or ASTR 016 ;
One Astronomy 100-level and one Physics 100-level offering (normally PHYS 107 , but the department may approve exceptions);
MATH 015 *MATH 025 MATH 027  or MATH 028 MATH 033  or MATH 034 .


* Half-credit course
ENGR 006 and PHYS 003 together may be substituted for PHYS 007. In some cases, with permission from the department, PHYS 003 alone may be substituted for PHYS 007.
§ In some cases, with permission from the department, PHYS 004 and a placement test may be substituted for PHYS 008 
† PHYS 083 is an alternative to PHYS 081 and 082 for students to meet the advanced lab requirement if they will also take ENGR 072 

Honors Program

Honors Major Preparations

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

Mechanics (PHYS 111 ),
Electrodynamics (PHYS 112 ),
Quantum Theory (PHYS 107 ),
Statistical Physics (PHYS 114 ),
Honors Thesis (PHYS 180  )
          Note: In some cases, elective seminars may be used as physics honors preparations.

Any of the seminars from the astronomy program,
plus: Electrodynamics (PHYS 112 ),
Quantum Theory (PHYS 107 ),
Statistical Physics (PHYS 114 ),
Honors Thesis (ASTR 180 )

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

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 Preparations

Physics Minor: One of the following seminars PHYS 107 , PHYS 111 PHYS 112 , PHYS 114  

Astronomy or Astrophysics Minors: 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

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 sequential nature of the Physics and Astronomy curricula makes careful planning for study abroad a necessity. 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. With careful planning, 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).

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 complimentary topics