Subject XYZ 101 in U.S. colleges/universities. Why 101?

Factual Questions
21

At a lot of institutions, three-digit course numbers beginning with a leading zero frequently indicate “nonspecialist” or “non-major” courses, as opposed to the introductory courses in the regular program of study that constitute the “100-level” sequence.

So, for example, Physics 120, 121, 122, 123 could be the standard four-course sequence for beginning physics majors, while Physics 051 and 053 are less technical courses aimed at non-science majors interested in learning some general information about particular subjects in physics.

As suranyi notes, some highly prestigious institutions like Caltech have made kind of a point of retaining an earlier or idiosyncratic course numbering system that doesn’t follow this “100-level, 200-level, etc.” pattern, as part of their “brand”. For instance, Harvard also still uses 1- and 2-digit course numbers, while geek-happy MIT uses decimal fractions as course numbers, with the integer part being the number of the department or “course” it’s offered in. So, for example, Physics is designated “Course 8” at MIT, and the first introductory physics course is numbered 8.01.

22

Nowadays most colleges and universities have their catalogs available online, so you could browse some real-world examples if you want.

At the risk of repeating what others have said: It’s typical for every course that a college offers to be identified by a Department/Subject Area (like Chemistry or Sociology or Mathematics) and a course number (like 101 or 210); there will also be a course title, telling you, for example, that “MATH 210” is Calculus I.

The course numbers are most commonly all three-digit numbers, though some institutions use four- or two-digit numbers. The system—if there is a system—for assigning course numbers will vary from school to school, with one constant being that higher-numbered courses tend to be more advanced than lower-numbered courses (CHEM 101 might or might not be a prerequisite for CHEM 102, but it would virtually never be the other way around), with the first digit often indicating, in a broad sense, the level of the course or the year at which it’s most commonly taken.

It’s also fairly common for classes numbered below 100 (like 095) to be remedial/developmental classes (often in math or English) that aren’t really college level and don’t offer college credit, but which need to be taken by some students before they’re ready for college-level classes.

23

IIRC, in the good old days (not sure if it’s still true)… at the University of Toronto.

The first digit indicated the year. 1xx courses were first year undergraduate (“freshman”).

2xx was 2nd year, 3xx was 3rd year, 4xx was fourth yer. then you got a bachelors.

The increasing number indicated level of difficulty.
01-09 was for “outside” students - i.e. Physics 101 was for Arts students.
10-19 was for other disciplines - i.e. Physics 110 was for Biology or Sociology students who wanted an intro to physics - a bit more scientific than 101.
20 or 30 level was for lower-level specialization - say, Chemistry or Architecture would need a bit more than a smattering of physics, it was needed for their discipline.
40 and above were for specialists in the field.

Hence, Physics 101 was the simplest, least detailed course you could take in physics. Physics 150 was for Physics majors; Math 150 was detail Calculus, Math 140 was Linear ALgebra that you had to take as a Physics specialist.
Some disciplines, like Chemistry, only offered Chem 120 for beginners - unless you were Arts or someone who took Chem 101.

By second year, you are getting into assorted courses - Chem221 was Organic intro, Chem 225 was Reactions, or something like that. It’s been a while.

So “Basket Weaving 101” is shorthand for “not only is it an introduction to the topic, it is the simplest introduction we can offer.” it assumes you probably know nothing at all of the topic. I assume a large number of universities used this shorthand in the 1960’s to 1990’s, since the use of “101” is common from what I’ve seen.

And the calendar would list a track of courses to get a “Science Degree”:
You must take PHY130, Math 130, Plus 3 of the following…
2nd year, PHY 223, MATH 221, MATH 225, and CHEM 225, and 3 of the following…
etc.

24

Oh, and each course had pre-requisites. To take Whatever-220 you must have taken Whatever-120 or higher number.

Typically, if you took Physics 101 (PHY 101) or Astronomy 101 (AST 101) you took no more physics or astronomy classes. You concentrated on courses like FAS 252 Fine Art and the Use of Visual Metaphors the next year, and savoured your near-brush with science for the rest of your career.

And the reason for increasing numbers corresponding to increased difficulty - the calendar would say - “Take PHY 130 or higher”. (i.e. PHY 140, PHY 150) Take any BIO 220 or higher (biology) to fill this requirement, etc. “Take at least one of ACT 221, ACT 225, or ACT 230” (Accounting). The numbers made it easier to group.

25

I don’t know if it still does, but twenty-five (sheesh) years ago my school used letters to designate the level of the class - “A” to “D”. That was followed by a number, which I think was three digits. So for example I have a foggy memory of taking C056, but I can’t remember now that subject or title of that class. Probably some filmmaking class.

26

I just skimmed the thread, so I hope I’m not about to say something already covered.

Another reason for starting at 100 is typography. In the days of letterpress or Linotype, making columns of numbers align was more difficult than it is with the computers of today. One thing that made it easier was to make sure every number had the same number of digits.

So if you planned to have more than 100 but less than 900 different classes per department, 3 digits starting with 100 was how you made things better for the poor souls setting type for the catalog.

27

In my four-year, well-known, highly respected university, the undergrad courses are all two digits. Grad student courses are given three digits. There are some courses taught to both grads and undergrads simultaneously. They’d be listed as 166 and 66 in the catalogue.

28

My General Relativity course was “MATH 666”. The handful of us taking the class would make jokes about “tensors from Hell” and “indices of the Beast”.

I don’t miss coursework. :stuck_out_tongue:

29

All that varies with the institution, though, and I don’t think I ever had a Blah 101 course at any time. In the UC system, for instance, upper division course numbers usually run from 100 to 199, 300s, 400s, and 500s are different types of graduate courses usually depending if they’re considered to be general academic topics, professional core curricula, and so on.

30

Johns Hopkins currently does first a 3-digit code for the Department (was not always like that, at some point they added leading and trailing zeros where necessary to make them all 3-digit), then a decimal, then 100-299 for lower level undergraduate, 300-499 for upper-level undergraduate, 500’s for upper level internships/research/independent and 600+ for Graduate. Thus “030.205 Introductory Organic Chemistry I”

Lower 100 courses tend to be those with little or no prerequisites. They do not, however, always use “101” for the “basic” or “first” course in a subject. Some subjects start rather at 110 or 111. Back in the early 80s it was rare to have a “101” at JHU, they have since grown more uniform with the other schools, so during the time I put in there I don’t think I ever had an actual “101”.

31

To make this even more confusing the place that I got a degree from, which shall remain nameless, numbering could vary between departments. In otherwords in some departments they had 101 courses but those were for non majors and the real freshman courses were number in the 200’s. However other department had the freshman courses for both majors and non majors in the 100 levels. (Oh, and it was a 3 digit code.) I’m not sure if anybody else had anything that was as confusing as that.

32

I think a lot of places have artifacts in their numbering systems. For instance, at my university in the Computer Science department there were only two 100 level courses: 127A and 127B, more or less intro to programming. If you already had some experience, you were permitted to take 227, which was an accelerated one semester version of 127A and B. As far as I know, there was no CSC101, though if there was it was some weird exploratory thing that was probably pass/fail that almost nobody took. It was, in fact, possible to get a BS in Computer Science without taking a single 100-level comp sci course if you took 227, which I did (well, 227H, but whatever, same course different discussion section).

My guess is that at some point there was a CSC101 and 102, and then they added a new intro to programming class called 127, and then eventually 101/102 were deemed superfluous or obsolete, but they kept 127 called 127 due to inertia or to prevent confusion. (In fact, the sister department that split off from the comp sci department has its initial course numbered at 130, which is basically 127 but with Python instead of Java, long story, but presumably that number was intended to suggest it as an alternative before the department split – though in fact both departments will accept 127A+B/227/130 as equivalent).

In general, the CS department was in “tiers”, courses that roughly followed one another would change the first digit but leave the other two constant (except 127A/B). For instance, Intro to C was (IIRC) 352, and Compilers (where you wrote a compiler for a minimal subset of C) was 452. Discrete Math was (again, IIRC) 244, Introduction to Discrete Structures (basically data structures and intro to algorithms) was 344, and Algorithms was 444 – granted technically 344 could be followed but by either Algorithms or Automata, which was a different number.

33

Subjects are often numbered the way rooms and floors are. The first floor is 1…, second floor is 2…, so the first room on the first floor is 101, and the first class in the first year is 101. The second class in the first year is 102, and the first class in the second year is 201. Simple, logical, and it worked for me.

34

I think that was the intention, but in my experience it rarely works out that way. For instance (again, at my university), in the English department 101 and 102 were the first and second courses, yes… unless you passed the English AP exams. In which case two terms of English were still required, but you’d take 103 and 104 instead. Or 108H if you were an honors student. Nobody ever took 101, 102, 103, and 104 in sequence, it was EITHER (101,102), (103,104) or (108H)*.

Or the physics department, where 101 was more or less rigid body kinematics without calculus, and 102 was thermodynamics, acoustics, and optics without calculus – versus 124 and 125 which was the same with calculus – versus 152H and 153H which were the same except honors. And, in fact, while the next two (non-elective for majors) courses were 200-level, they were mostly independent of the two 1xx courses, and it was common for students to take one in the 200-track and one in the 100-track in parallel.

  • A few special cases may have done something odd like (101,104) or (103,102), but in general.
35

Heck, I am surprised and impressed that you can all remember all this detail, 'cos I’m sure I don’t. Is age 52 too young to go senile? :eek:

May I say thank you very much to all who have responded and I apologise for my absence as I have been variously away from home and also having only sporadic internet for a wee while.

Thank you all for helping with what was, I suppose, a bit of a silly question. Oh, I do love this board because people understand that sometimes utterly non-important things nag at one’s brain and it is all right to ask about them. :slight_smile:

36

There can be other artifacts in course numbering, too. For instance, some years back, the physics department head at Montana State decided that he ought to get to know all of the physics majors, so he created a new one-credit course (with himself as the instructor) and required it of all physics majors. It was basically an overview of what every physicist should know about modern physics. He assigned it the number PHYS 137, because, well, 137.

37

College courses are organized into blocks denoting similar difficulty. There are 100s level courses, 200s level courses, and so on.
Numbers within each level similarly denote increasing complexity. For instance, Freshman generally have to take English 105 and English 109, which cover the basics you need to know to write for college (boor reports and the like). English 101 is English as a Second Language. English 102 is Simple Subjects and Verbs, for folks who still don’t get that well enough to pass English 105.
No idea why they do that, but I assume it allows some standardization while the exact names of those courses may vary from institution to institution.

38

Not exactly: History 101 was the beginning to the protestant reformation, History 102 was the protestant reformation to the present. Freshmen were free to take either.
But otherwise, yes.

39

One more point: Introduction to Communications Sciences (which was required for all LIberal Arts majors), was CommSci 102, and had as prerequisite English 109, which had as prerequisite English 105, so nobody took CommSci 102 as a Freshman, and nearly everybody took it as a Sophomore.
And my father, who taught it, would routinely have to send a large percentage of his students back to English 101.

40

At my school, you could take a year long introductory biology class, 101 for the first semester, 102 for the second. But that was for non-science majors. Science majors were expected to take 105 and 106. 200 level bio classes had 105 and 106 as prerequisites, you couldn’t take advanced biology classes if you just had Bio 101 and 102. Almost all science subjects had survey classes for dummies that were 101 and 102, for people who were never going to take another science class in their lives if they could help it, and 105-106 classes for people who were going to major in science. If you were a bio major, you were required to take chemistry, but you couldn’t take chem 101 and 102, you had to take 105 and 106.

And courses lower than 100 level were remedial classes that did not count towards your degree. You had to take a year of math, and Math 101 and 102 would satisfy that. But if you were severely behind in Math you’d have to take Math 91 and 92, before you were allowed to take 101 and 102.