I've been teaching out of the Six Ideas that Shaped Physics for a while now. One of the things I really like about it is the approach to Newton's laws. Essentially he starts with conservation of momentum and ends with Newton's third law. He focuses much of the series on the concept of interactions, making it clear that particles swap momentum during interactions while the particle pairs swap potential energy for kinetic energy. I've found this fun to teach but I get caught up not having a simple unit for momentum.
I've been heard saying: "When that ball hits the other one, 7 kilogrammeterperseconds are swapped." I say it really fast because I want the students to recognize that momentum has been transfered from one particle to the other. I'm writing this post to throw out a suggestion: How about we use the unit "Pom" for momentum? The word comes from a shortening of what I sometimes call momentum (pomentum) to remind them that the letter we use is p.
Why would this be useful? Well, then I could say "When that ball hits the other one, 7 poms are transfered" Rolls off the tongue, doesn't it? Also, if you've read the Six Ideas books you'll know that he describes force as simply an accounting trick to keep track of a continuous transfer of poms. That's why the units of force is poms per second (or, if you insist, the awkward "Newton"). If you want to know if something's going to hurt, you just have to see what the pom rate would be.
I've seen how students relate everything to Newtons, or force. I think, though, and here I think Thomas Moore would agree, it can be very satisfying to try to find how the momentum is being transfered in all the various interactions involved in a physics event. What do you say?
Friday, December 17, 2010
Friday, December 10, 2010
Grading with my voice
A few people have asked me for some more detail about how I use screencasting to grade papers so I thought I'd post this.
As a physics professor I don't grade nearly as many writing assignments as my colleagues in other disciplines but I do take seriously my job to help all my students improve their writing. When I first started grading such papers, I would write comments on each draft and provide a grade via some sort of rubric. The rubrics started really as requirements that could be met in various ways and have evolved to fully fleshed out rubrics with careful descriptions of what it takes to get a check mark in columns like "meets basic expectations."
I quickly realized that giving the students the type of feedback I really thought they could use took a lot of time and effort, and I found that meeting with the students about their writing was one of the best ways to do this. However, those appointments are hard to schedule, especially in a semester like I have now where all three of my lecture courses have heavy writing requirements (my First Year Seminar is writing intensive, my junior-level advanced lab course has writing a grant as 80% of the points, and my fully online course for teachers has a lesson plan as a major assignment).
I realized that the screencasting I was doing for my lectures could also be used to simulate the office experience with students. I use my pen tablet mouse to mark up the documents digitally (using either Jarnal or Adobe Acrobat, or FoxIt reader) and I use Jing to record my voice while explaining my concerns with the paper. Here's an example. In that example you can see how I mix in discussion of content, style, and how it meets the expectations. You'll also see that the 5 minute limit that Jing holds me to wasn't enough (so I just did a second one). Typically I get my comments done in under the five minute limit (though the reading of a typical paper still takes me something like 20 minutes).
I ride the bus a lot and I like to use that time to grade. What I've taken to doing is marking up the papers in regular ink with little notations to myself about what to say. When I'm back in my office I then open the digital document, grab my pen tablet, and begin. I transfer the marks that are necessary all the while holding a pseudo-conversation with the student.
I've gotten a lot of good feedback about this from my students. They really like having the screencast at their disposal for pausing and rewinding. One student told me that he opens his paper on his computer before playing the screencast and he makes changes immediately, while pausing the playback. Others have said that they really feel they understand what I'm looking for after watching. There's also been an interesting study on the preferences of students for the type of feedback they'd like, comparing regular comments, track-changes in Word, track changes with audio, and what I do. The upshot is that my way was strongly preferred in their survey.
I'd love to hear how others use a similar system. Feel free to drop me a line here in the comments or on twitter @arundquist.
As a physics professor I don't grade nearly as many writing assignments as my colleagues in other disciplines but I do take seriously my job to help all my students improve their writing. When I first started grading such papers, I would write comments on each draft and provide a grade via some sort of rubric. The rubrics started really as requirements that could be met in various ways and have evolved to fully fleshed out rubrics with careful descriptions of what it takes to get a check mark in columns like "meets basic expectations."
I quickly realized that giving the students the type of feedback I really thought they could use took a lot of time and effort, and I found that meeting with the students about their writing was one of the best ways to do this. However, those appointments are hard to schedule, especially in a semester like I have now where all three of my lecture courses have heavy writing requirements (my First Year Seminar is writing intensive, my junior-level advanced lab course has writing a grant as 80% of the points, and my fully online course for teachers has a lesson plan as a major assignment).
I realized that the screencasting I was doing for my lectures could also be used to simulate the office experience with students. I use my pen tablet mouse to mark up the documents digitally (using either Jarnal or Adobe Acrobat, or FoxIt reader) and I use Jing to record my voice while explaining my concerns with the paper. Here's an example. In that example you can see how I mix in discussion of content, style, and how it meets the expectations. You'll also see that the 5 minute limit that Jing holds me to wasn't enough (so I just did a second one). Typically I get my comments done in under the five minute limit (though the reading of a typical paper still takes me something like 20 minutes).
I ride the bus a lot and I like to use that time to grade. What I've taken to doing is marking up the papers in regular ink with little notations to myself about what to say. When I'm back in my office I then open the digital document, grab my pen tablet, and begin. I transfer the marks that are necessary all the while holding a pseudo-conversation with the student.
I've gotten a lot of good feedback about this from my students. They really like having the screencast at their disposal for pausing and rewinding. One student told me that he opens his paper on his computer before playing the screencast and he makes changes immediately, while pausing the playback. Others have said that they really feel they understand what I'm looking for after watching. There's also been an interesting study on the preferences of students for the type of feedback they'd like, comparing regular comments, track-changes in Word, track changes with audio, and what I do. The upshot is that my way was strongly preferred in their survey.
I'd love to hear how others use a similar system. Feel free to drop me a line here in the comments or on twitter @arundquist.
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