EPSS 264: Order of Magnitude Earth and Planetary Sciences ("OOMPS")

UCLA WINTER Term, 2023.

NOTE: The feedback from previous participants in this class may be found here

Many people have had little practice in making rough estimates or order of magnitude assessments of physical problems, and even less practice at "talking through" a problem with others. The reasons for this are no doubt many and varied, but a key problem is the tendency for rote memorization to take precedence over understanding, presumably because it seems "easier" in a narrow-minded way. All TAs and lecturers know about this problem with undergraduates but, amazingly, the same thing extends all the way to graduate level classes and, perhaps, beyond. The problem with this is that it leaves you with a diminished capacity for understanding new things, or any things that have not already been presented in a pre-packaged, class format. I don't like that.

The objectives in teaching OOMPS are

  • To emphasize the importance of physical understanding and approximation in science.
  • To encourage you to "think on your feet" and "talk on your feet".
  • To encourage you to take a broad perspective and to be scientifically judgemental of others and, especially, of yourselves.
  • To help you think about, practice, and get better at, scientific speaking and writing.
  • To have fun, at least as much as you can have fun in a class.

    The principal targets are pre-qualifying exam EPSS graduate students. No great mathematical sophistication is needed for this class: we are interested mostly in reasoning, not mathematical devices. Not coincidentally, the things we will do in OOMPS may be of value in your qualifying exam, where basic understanding, simple calculations and broad knowledge are the main things tested. It's also fine for post-exam students to take this class.

    The format of the class will probably change as we go along, depending on your needs and interests. Here are my current ideas:

  • It must be interactive to be effective (i.e. you will do things, not just listen to me)
  • You must take it for credit to be involved. Auditors will not have sufficient commitment.
  • The class size is limited by me in order to maintain reasonable interaction with each person.
  • There will be no final exam.

    What We Will Do
    In the first (and largest) part, we will discuss basic problems from an OOM perspective. We will focus on problems appropriate to EPSS, but not exclusively. The aim here is less the particular brand of science than the style of thinking about science. The purpose is to inculcate physically-based reasoning and also to promote effective on-your-feet communication.

  • I will kick-start the class with some examples of order-of-magnitude reasoning.
  • We will solve simple problems in an order-of-magnitude, physically-based way. We'll do this in-person, in-class, interactively.

  • In the second part I want to do the following. You are required to attend the EPSS colloquium each week. After each colloquium, you should independently email me your "grades" for the speaker according to simple criteria to be discussed. I will combine your assessments and we will talk about them in the next seminar meeting. In addition, I will ask one of you to present a 5 or 10 minute off-the-cuff overview of the colloquium, which we will also discuss as a group. Category guidelines are listed here.

    In this way, I hope to encourage your critical listening skills, as well as provoke your judgement about the speaker's style and content.

    In the third part, we will address scientific speaking and writing directly.

    What You Should Do Now

  • Make sure that you have my agreement for taking this class (4 units).

  • If you have ideas or questions or thoughts about what you would like to get from this class - let me know.

    OOM thinking won't work without a platform of basic numbers that you should carry in your head. Over the xmas vacation, you should have made sure that your brain carries the fundamental physical constants. I use MKS units (kg m s) for everything.

    Meeting Times
    Primary = TBD

    Backup = TBD

    David Jewitt.

    Other Classes