Early Dismissal

I grew up in Buffalo. I remember a day when it was so snowy and windy that I couldn’t see a foot in front of me as I walked to the bus stop. A tree had blown over, and I nearly got entangled in the top branches because I didn’t see them until I was in them. We had a regular day of school that day.

Today, school let out early. I was able to leave by noon, when there was a VERY LIGHT dusting of snow on the ground. I didn’t even have to brush off my car. Freezing rain was in the forecast, but from where I am now sitting, cozy in my home office watching a few fluffy snowflakes drifting down onto the bird feeder, I just have to shake my head and sigh.

So, am I catching up on schoolwork? Sleep? Neatening the house and cleaning the bathroom? Washing the soup pot from Sunday that I still haven’t taken care of? No, I am blogging. This is why this blog was a bad idea.

But I think I can afford the time to tell you about the exciting online course I am taking.

I’m taking a course from North Carolina State University called Matter and Interactions. That’s also the name of the textbook, and one of the book’s authors, Dr. Bruce Sherwood, is the instructor. This particular course is intended for high school teachers, and it is introducing us to several ideas that we may not have applied in our teaching before.

(1) Physics in the modern era acknowledges that major advances occurred in the 20th century, changing the traditional “Newtonian” model.

(2) Physics in the modern era relies as much on computational methods as it does on experiment and theory.

(3) There are several fundamental principles that form the core of physics knowledge and which are applicable from atoms to galaxies, and these should be the principles that form the core of the curriculum.

As teachers, we are viewing lectures, reading the textbook, solving homework problems, and writing computer programs to model physical systems, and we are reflecting on how what we are learning might affect the way we teach.

I am thrilled to be learning some computer programming! You might think that it is not a very useful sort of computer programming (excuse me, coding), because I will not end up with any java applets for use in my class or applications for the web, or cute little games. I am learning to use vpython, which is a part of the python programming language that makes little visual models. For example, last week I had to make a program that included a spaceship, planet Earth, and Earth’s moon. The spaceship started out near Earth (in the picture, it is where the yellow line begins, on the left) and had a certain initial velocity. Due to gravitational interactions, it had an unpredictable but calculable path between the Earth and moon until it crashed into Earth (the green arrow coming off the Earth actually shows the spaceship’s momentum at the moment of crashing.) Depending on what I gave the spaceship for initial velocity, the path of the spaceship had a lot of different shapes that I explored in the course of the assignment.

Here is what one spaceship path looked like:

orbit crash

Notice that the Earth (blue dot on the left) and the moon (gray/white dot on the right) don’t move, so this is an unrealistic representation…but I will eventually program that stuff in also.

One of the reasons that this kind of computer model is so exciting is that you CAN’T solve this problem using calculus. You CAN’T send spaceship after spaceship out with a different initial velocity and see where it goes. But you CAN let a computer take its time and calculate the same little calculation over and over again with slightly changed conditions, and see where you wind up afterward!

In addition to coding, we are doing the traditional introductory physics topics in a very untraditional way. After a brief review of vectors, we immediately jumped into momentum (a topic often covered fairly late in mechanics). The relativistic expression of momentum, that is:

p = γmv

where γ (the greek letter gamma) is the factor


and c is the speed of light.

Usually, in introductory physics, relativity is an afterthought. At the end of the year, if we still have some time, we do some relativity. And maybe we get to the relativistic momentum, and maybe we don’t. I am also looking forward to the promised material on statistical mechanics, which I have never felt very comfortable with.

So far I am liking the different approach. And I keep getting ideas, which is great fun!

4 Responses to “Early Dismissal”

  1. keiko Says:

    you do know that i was a member of the navigation team for mariner and viking project? the weekend of feb 1, i had a reunion with the navigation team at JPL…a 35 yr reunion. i was a member of the orbit determination group… trajectory group was also there. it was incredible to see all these folks after 35 yrs. maybe i will send you a copy of double precision orbit determination book under which we programmed the navigation.

  2. teawithbuzz Says:

    I would be curious to see how you did that! Did you do it in FORTRAN?

  3. April was two months ago « TeaWithBuzz Says:

    […] we had a talk by my NCSU professor, Bruce Sherwood.  He’s the one who taught me to use vpython and completely changed my view of introductory physics.  I’ve been promoting vpython with […]

  4. April was two months ago | Phasing Says:

    […] we had a talk by my NCSU professor, Bruce Sherwood.  He’s the one who taught me to use vpython and completely changed my view of introductory physics theory.  I’ve been promoting vpython […]

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