FAQs: Introductory Courses

If you have any feedback on these questions/answers, or if you would like a new question added to this list, please contact David Morin.

GENERAL QUESTIONS RELATED TO PHYSICS COURSES:

  1. In deciding between two (or more) courses with different levels of difficulty, how can I be sure that I sign up for the right one?
  2. I want to take three science courses (among Math, Physics, Chem, Bio, EngSci, CompSci, Astro, etc.) in my first semester. Is this advisable?
  3. What are the physics requirements for my concentration?
  4. I took a college physics course somewhere other than at Harvard. Does it count for my concentration?
  5. I did very well in my high school physics course, but it was a number of years ago so I’m a bit rusty. Which course should I take?
  6. Which multivariable math course will help me more in my physics courses: Math 21, or something higher?
  7. I am planning on taking math at the 21 level. Should I take the Math or Applied Math version?

SPECIFIC QUESTIONS ABOUT THE INTRODUCTORY PHYSICS COURSES (PHYSICAL SCIENCES 2/3 and 12A/B, PHYSICS 15A/B/C, 16):

  1. Which of PS2, PS12a, 15a, 16, or 19 should I take?
  2. Which physics courses satisfy the premed requirements?
  3. When do students take normally PS2/3, PS12a/b, Phys 15a/b/c, 16, and 19?
  4. Can I switch from one of the PS2/3, PS12, 15, 16, and 19 courses to another after a few weeks if the difficulty isn’t right?
  5. What benefits do I get from having taken an AP physics course in high school?
  6. I reached a very high level of math in high school (and did very well in it), but I had only a weak physics course (or none at all). If I am interested in physics now, which physics course should I take?
  7. What level of math is needed for PS2/3 and 12a/b?
  8. What level of math is needed for 15a, 16, and 19?
  9. What level of math is needed for 15b?
  10. Can I take PS12b after taking Phys 15a?
  11. PS12a and Phys 15a seem to cover many of the same topics as a high school AP mechanics class. Does that mean I’ll be bored in them?
  12. Is it ok to postpone Phys 15a to freshman spring or later?
  13. Do I need a certain Harvard physics placement-test score or a certain AP score to get into Physics 16?
  14. Which one of the Phys 15a, 16, 19 courses should I take?
  15. Is the workload for the Math 55/Phys 16 and the Math 25/Phys 16 combinations manageable?
  16. Can I take Phys 15b before (or concurrently with) Phys 15a? And likewise for Phys 15c/15b, and for 143a/15c?

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GENERAL QUESTIONS RELATED TO PHYSICS COURSES:

  1. In deciding between two (or more) courses with different levels of difficulty, how can I be sure that I sign up for the right one?
    In most cases, you can’t. The best you can do is make an educated guess by reading the available materials (course catalog, course webpages, departmental documents, Q Guide, etc.) and by talking with your various advisors and also with students who have taken the courses. Then it comes down to shopping the possibilities. Sometimes there is simply no way to determine which course is the right one for you without checking them all out. This is all the more true because even for a given course description and syllabus, two different professors might end up teaching two highly different versions of the same course. In the event of conflicting time blocks, it’s generally best to start out by attending the higher-level course (for example, Phys 16 instead of Phys 15a) and then dropping to the lower one if the workload is too much. But beware: courses invariably start off a little slow and then pick up the pace, so don’t be fooled by an initial light workload. Also, if there is a possibility that you might switch into a course after a couple weeks, keep an eye on the assignments and other requirements.
     
  2. I want to take three science courses (among Math, Physics, Chem, Bio, EngSci, CompSci, Astro, etc.) in my first semester. Is this advisable?
    The answer is a definite maybe.It depends on many things - your background in these areas, learning style, goals, extracurriculars, and so on. You are strongly encouraged to talk with your freshman advisor about the particulars of your schedule, and see what works best for you. But one piece of advice: In your first semester, it’s best to play it safe and not get in over your head. There will be plenty of time to get creamed in future semesters if you so desire. Courses invariably end up being more difficult than anticipated, but in the (extremely unlikely) event that you are completely bored because your schedule is too easy, you can simply ace all your courses and get involved in a few more of the zillion extracurriculars on your wish list. Things could be worse.
     
  3. What are the physics requirements for my concentration?
    You should check specifically with the advisors of your concentration. But a few comments: The general rule is that even if you have AP physics credits, you still need to take the physics course(s) here at Harvard. And for the concentrations that require PS2/3 or PS12a/b, it generally also suffices to take 15a/b; that is, there is no need to complete the 15 series by taking Phys 15c. But again, you should take this paragraph with a grain of salt and be sure to check with your concentration for the official rules.
     
  4. I took a college physics course somewhere other than at Harvard. Does it count for my concentration?
    You should check specifically with the advisors of your concentration, because the rules on this vary from department to department.
     
  5. I did very well in my high school physics course, but it was a number of years ago so I’m a bit rusty. Which course should I take?
    This is highly student dependent, so it's best if you get some one-on-one advice by stopping by to talk with Howard Georgi or David Morin (contact info at the end of this page). But in short, it depends on how well the material sunk in originally, and also how comfortable you are with reading up on topics that you find you need to review. And comfort level with math also plays a part.
     
  6. Which multivariable math course will help me more in my physics courses: Math 21, or something higher?
    If your goal is to obtain the math tools that will help you in physics, then Math 21 (or Applied Math 22) is probably the right course for you. However, if you are someone who likes math simply for math’s sake, and if you are confident that you can pick up math concepts as needed, then Math 23, 25, or 55 is probably the way to go. A difficult decision arises if you like math for math’s sake, but you’re not confident that you can pick things up as needed. At any rate, shop a couple of the courses if you’re undecided, and keep the option open for switching within the first couple weeks. And be sure to discuss things with the advisors from the Math department, who offer a large number of advising opportunities during freshman week.
     
  7. I am planning on taking math at the 21 level. Should I take the Math or Applied Math version?
    It depends on what you want out of the class. The two courses cover basically the same material, but the Math version is more proof based, while the Applied Math version has more applications. You should discuss similarites/differences with the advisors from the Math department. But in the end, just as with many questions of this type, it probably comes down to shopping both classes and seeing which one is a better fit for you. The courses are also organized differently, so as always, shopping is important to see which style you like better.
     

SPECIFIC QUESTIONS ABOUT THE INTRODUCTORY PHYSICS COURSES (PHYSICAL SCIENCES 2/3 and 12A/B, PHYSICS 15A/B/C, 16):

  1. Which of PS2, PS12a, 15a, 16, or 19 should I take?
    It depends on you background, interests, and schedule. PS2/3 is geared toward students in the life sciences. It is a physics course that contains many biological examples and applications. PS12a/b is designed as a foundational course for students interested in the physical sciences or engineering, but who have not yet chosen a concentration. It has a large numerical component. Both PS2/3 and PS12a/b cover more topics but in less depth than Phys 15a/b. Phys 15a/b/c is required for Physics, Chem/Phys, and Astro concentrators, although many students from other concentrations also take this sequence. Phys 15 involves more derivations and more problem solving than the PS sequences. Phys 16 is the honors version of Phys 15a (and like 15a, it funnels into 15b). Phys 19 is an alternative to Phys 15a and 16 and covers a wider set of first-principles, foundational topics for theoretical physics and is intended to give a broader preview of later courses in the physics concentration, but assumes only a familiarity with single-variable calculus as a prerequisite. See also the "Which one of the Phys 15a, 16, 19 courses should I take?" question below. The main point of 15a and 16 is to learn physics that is required for more advanced courses and to hone one's problem-solving skills. The main point of Phys 19 is to provide a comprehensive grounding in the concepts and mathematical tools of theoretical physics that show up in the rest of the physics concentration, especially but not only for students who are curious about physics but who may have limite
     
  2. Which physics courses satisfy the premed requirements?
    The premed requirement is two semesters of physics. So you can take PS2/3 or PS12a/b or Phys 15a/b or Phys 16/15b. Other combinations also work, for example Phys 15a and then PS12b. But be aware that the PS12 sequence starts with 12a in the spring semester.
     
  3. When do students take normally PS2/3, PS12a/b, Phys 15a/b/c, 16, and 19?
    PS2/3 is generally taken in the junior year (about 75% are juniors), because premed students need it for the MCAT. PS12a/b is taken anywhere from freshman to junior year. Phys 15a is a foundational course for the Physics, Chem/Phys, and Astro concentrations, so these concentrators take it freshman year (freshmen make up slightly more than half of the class), or perhaps sophomore year for Chem/Phys. However, students in related science concentrations who opt for 15a often take it in the sophomore or sometimes the junior year. Phys 16 is generally taken freshman year, although it’s certainly open to everyone. Phys 19 is intended mainly for freshman, but also for students from other years and from other fields who may be interested in learning a lot of physics either to change their area of focus to physics or to serve the needs of their original areas of study. Note that each of the 15a/b/c courses is taught in both the fall and spring semesters. Phys 16 and 19 are offered only in the fall semester.
     
  4. Can I switch from one of the PS2/3, PS12, 15, 16, and 19 courses to another after a few weeks if the difficulty isn’t right? Yes, but keep close tabs on what you need to do to enter a course late. It is your responsibility to check that work can be transferred from one course to another. Keep an eye on the add/drop deadline and any possible early exam dates. Be aware that the PS12 sequence starts with 12a in the spring semester.
     
  5. What benefits do I get from having taken an AP physics course in high school?
    If you have enough AP credits overall, you can declare “Advanced Standing” which makes it possible to obtain a Master’s degree through the AB/AM program or to graduate in three years. However, it turns out that very few students end up taking either of these routes, so in nearly all cases the sole benefit of a high school AP course is that it gives you the background to start with a higher-level course here at Harvard (for example, Phys 16 instead of 15a).

    But one major exception to this is with the foreign-language requirement; a sufficient score on the SAT II test or on the Harvard placement test allows you to skip the otherwise required yearlong language course requirement. The full rules are here.
     
  6. I reached a very high level of math in high school (and did very well in it), but I had only a weak physics course (or none at all). If I am interested in physics now, which physics course should I take?
    If your math level is very high, and if you are comfortable reviewing and picking up things on your own, and if you want to enthusiastically put in the extra effort, then Phys 16 might be the right course for you. Otherwise, 15a or 19 should work. At any rate, you can shop 16 and see how it goes. Of course, you may also choose PS2 or 12a, depending on your concentration.
     
  7. What level of math is needed for PS2/3 and 12a/b?
    The prerequisite for both courses is Math 1b.
     
  8. What level of math is needed for 15a, 16, and 19?
    The corequisite for 15a and 19 is Math 1b; this will work fine if you are very confident with the Math 1a material. But if you’re shaky with it, then you should probably finish Math 1b before taking 15a or 19. The corequisite for 16 is Math 21a. But perhaps more importantly, a very high level of comfort with Math 1b material is needed for Phys 16.
     
  9. What level of math is needed for 15b?
    The prerequisite is math 21a. So if you took Math 1b concurrently with Physics 15a or 19, you should delay taking 15b until you have completed Math 21a. There are exceptions to this if you feel confident in your ability to read up on the 21a material on your own before you encounter the applications in 15b. But this is risky, and you should definitely talk with Howard Georgi or David Morin (contact info at the end of this page) if you are thinking of doing this.
     
  10. Can I take PS12b after taking Phys 15a?
    Yes. But be aware that the PS12 sequence starts with 12a in the spring semester; so you would need to skip a semester if you take 15a in the fall (15a is also offered in the spring). The Phys15a-PS12b combination counts as equivalent to the 12a/12b sequence for all concentrations, as far as we know, but you should always verify such substitutions directly with your concentration, since they have the final say on what is required. If you plan to take 12b without taking 12a first, you should expect to invest time to catch up on the computational/numerical aspects.
     
  11. PS12a and Phys 15a seem to cover many of the same topics as a high school AP mechanics class. Does that mean I’ll be bored in them?
    In most cases, the answer is a definite No. Although the topics are roughly the same as in a high school course, these college courses move much more quickly and study things in much more detail. So even if you aced your AP course, it is still very likely that you will find these courses challenging. However, there are certainly students who are ready for a course beyond Phys 15a, and this is precisely why we formed Phys 16. The goal of Phys 16 is to make sure that no student is bored. We’re pretty successful at this. Another option is Phys 19, which isn’t more technically difficult than 15a and doesn’t require more prerequisites than 15a, but covers a wider set of foundational topics in theoretical physics and is intended to give a broader preview of later coursework in the physics concentration.
     
  12. Is it ok to postpone Phys 15a to freshman spring or later?
    Definitely yes, up to point, and it depends on the concentration you choose. From a requirements standpoint, Physics and Astro concentrators can easily start in the spring of freshman year and still have plenty of time to finish the requirements. Sophomore fall can technically also work, but this will make things a little squeezed in later years. Chem/Phys concentrators can easily start in sophomore fall. However, requirements aside in any case, if you plan on going to grad school in Physics, the more important issue is your overall set of courses. If you start late, it will be more difficult (but still doable if you plan things right) to take the necessary courses that will prepare you properly. You should talk in person with Howard Georgi or David Morin (contact info at the end of this page) about this.




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  15. Do I need a certain Harvard physics placement-test score or a certain AP score to get into Physics 16?
    No, but these scores may be helpful in deciding if you want to start out in the course. In any event, if you are interested in Phys 16 and feel that you have the right background, then simply show up on the first day and see how it goes. You can always switch to Phys 15a in the next few weeks. Just be sure to keep an eye on the 15a material and to complete a problem set in its entirety for one of the courses during the week that you switch.
     
  16. Which one of the Phys 15a, 16, 19 courses should I take?
    Phys 15a covers Newtonian mechanics and special relativity, meaning roughly the same topics as an advanced high school course (although special relativity might not be covered in high school), but with a more in-depth treatment and with harder problems. Phys 16 covers more advanced topics in Newtonian mechanics and special relativity, as well as a glimpse of quantum mechanics. Phys 19 assumes less prior exposure to physics and mathematics than Phys 16, and covers a wider set of the foundational topics in theoretical physics, as well as some classical field theory, thermodynamics, and quantum mechanics, but with less extensive coverage of Newtonian mechanics than in 15a or 16 and with problem sets that tend to emphasize conceptual thinking. You should skim through the first problem sets and any lecture notes that are available on the web, and then see which class is most suitable for you. There is no clear-cut criterion for deciding, but a major consideration is that of time. Phys 15a and 19 will take a substantial amount of time. But Phys 16 will take more.<

    If you’re deciding between Phys 15a and Phys 16 and think there is a reasonable chance (say, greater than 15%) that you will take Phys 16, then you should start out there. In the event that you wish to switch to Phys 15a, we promise to make the transition a hassle-free one. (Homework credit will be transferred. Just be sure to do either one of the homework sets in its entirety during the week that you switch.) Furthermore, if you are someone who is thinking of taking Phys 16, then the first few Phys 15a lectures will probably be mainly review, so you have little to lose by trying out Phys 16. The topics in Phys 19 don’t line up as closely chronologically with Phys 15a and Phys 16, so it’s somewhat more difficult to switch between Phys 19 and Physics 15a/16.

    Any of the Phys 15a, 16, 19 courses is sufficient for the intro mechanics requirement for the Phys, Chem/Phys, and Astro concentrations (roughly half of the Phys concentrators come from each course).The advantage of taking 16 or 19 is that you will learn about many advanced topics; see the course syllabi for a complete list of these. Note that Phys 151 (Advanced Classical Mechanics) goes well beyond the level of Phys 16, so if you eventually take Phys 151, it matters less whether you take 15a or 16.
     
  17. Is the workload for the Math 55/Phys 16 and the Math 25/Phys 16 combinations manageable?
    The answer completely depends on your background, course schedule, extracurriculars, eagerness to put in huge amounts of time, and so on. Many students have taken these combinations in the past, and in most cases things turned out fine, but in some cases the workload was too much. In all cases it required a very focused effort. So if you’re planning on taking one of these routes, get ready to work! Don’t hesitate to drop to Phys 15a or to a lower math course after a couple weeks if things get out of hand.
     
  18. Can I take Phys 15b before (or concurrently with) Phys 15a? And likewise for Phys 15c/15b, and for 143a/15c?
    Although we don’t advise this, there have been some compelling cases in the past, and sometimes it has been done successfully. It depends on many things (your background, math level, courseload, learning style, etc.), so you should talk in person with Howard Georgi or David Morin (contact info at the end of this page) to sort things out.
     

We hope that you find these FAQs helpful. But if you would like some more personal advice, don't hesitate to email us or stop by our office hours:

Howard Georgi: email, office hours
David Morin: email, office hours