Wheat-dogg’s world
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We have just finished our first five weeks of school, and my Physics First students have had their first run-ins with three of the most basic, yet most confusing concepts in physics: inertia, velocity and acceleration. After 23 years of teaching the subject, I have come to realize that I need to spend quite a bit of time trying to solidify these concepts in students’ minds.

Blame those stinking preconceptions, or the obtuse explanations in physics texts, but it is just really hard to get students to grasp those three concepts. Sure, they can memorize the definitions, but few really understand what they mean. Without a decent comprehension of them, learning later concepts (like force and momentum) is appreciably harder.

One misconception about inertia is that it is a force. That is, to some students, inertia is a force that keeps you at rest. A passable first definition, but then these students fail to realize that inertia also keeps you going. When the idea of force comes a bit later in the course, then they confuse inertia with real forces like gravitation and friction.

Inertia is a property of matter. It is internal, not external. External forces support an object, or resist other external forces, or push or pull an object. Inertia cannot make an object move by itself; it only maintains the motion that the object already has. If the object is at rest, it “wants” to stay at rest. If it’s moving in some direction at some speed, it “wants” to keep that speed and heading.

After the parent-teacher confab last week, I came home to discover that Turner Classic Movies was coincidentally airing teacher movies, to commemorate the start of school. I unwisely let myself get sucked into the experience. (I overslept the next morning. Oops!)

You know the kind of movie I mean: the slightly schmaltzy, melodramatic kind that features a dedicated, sincere teacher who can see the best in his or her students and brings them (or drags them) to new academic achievements by sheer force of will. The list is practically endless, but there are a few that stand out as really good flicks.

TCM was showing “Goodbye Mr Chips” just as I got home. It wasn’t the silly musical version with Peter O’Toole and Petula Clark from the ’60s, but the original movie version from 1939, starring Robert Donat and Greer Garson. The movie follows the career of Mr Chipping (we never learn his first name) as he reminisces about his life, dozing by the fireside as an old man. It touches on some of the personal sacrifices and obstacles any career teacher makes, without getting too melodramatic about them.

Chips chooses to teach Latin, in some part because he passed over for promotion to housemaster, but largely because he enjoys his craft and working with his form 1’s. Chips seems a stodgy old man, even in middle age, until he falls head over heels for a younger woman, who returns his love. She helps mold Chips into a warmer, less reticent person, in the process opening new avenues of affection between he and his boys with weekly teas. Her death in childbirth leaves Chips stunned, but he soldiers on, leading his classes on the very day of her death, finding solace in the comfortable routine of coaching young minds.

No, not that one. I mean, “What grade does my child have in your class?” Which one did you think I meant?

We just had parents’ night here on Wednesday evening. At my school, this annual event gives the teachers a chance to meet their students’ parents and talk up their courses, and the parents a chance to learn something about what they’ve gotten their kids into. Like many schools, we’ve taken to putting homework assignments and other course materials on a portal. Our vendor, Edline, provides its clients the opportunity to place students’ grades online, so that both students — and parents — can see them.

We, however, do not, for reasons I will get into later.

Since Edline portals do not allow students to complete their homework online, I also use WebAssign to allow my students to do many of their homework assignments online. Most of the students actually like the site, and it permits me to maintain my gradebook online for each kid to see his or her grades. Parents, however, cannot. And therein lies the rub.

One of my parents was quite distressed that she could visit the WebAssign site, but could not sign in, unless she used her daughter’s account. The girl wisely kept that information to herself (well, I hope, anyway). This mother wanted to know why (1) she could not access WebAssign and its gradebook and (2) why we do not upload our grades to Edline.