Monday, October 30, 2006

Better than two bikes and the bee?

My friend, Marion, sent me this one. It's from Car Talk's series of Puzzlers.

Doing the Math on the Ever-Slowing Drive

It may not become the classic that Two Bikes and the Bee is, but it's right there with it in my book!

Sunday, October 29, 2006

Chicago's Most Haunted

Did you know that ghosts haunt the site of a theater fire in Chicago? No really! It was on the local news.

Check the video clip right here.

Read the text of the report here.

They wouldn't report it as fact if it weren't really a fact. They didn't even include the token, highly-edited soundbite from a low-level skeptic. Obviously... because the ghosts are really real.

Anyway, back to reality. Here's the lesson plan, teachers.
1. Make a list of "facts" as reported in the piece. Have students label each one as to how it was reported: as fact or as speculation.
2. Were alternate explanations offered?
3. Who supplied the photos that included "images" of spirits or ghosts?
4. What "weasel words" did the newscast use to circumvent journalistic accountability?

Super-Bonus: "Psychic Detective" Ken Melvoin-Berg and "PhyzBlogger Extraordinaire" Dean Baird have something significant in common. What is it?

Tuesday, October 24, 2006

Dodge Nitro TV ad

As I've been cheering on the DEtroit Tigers in the World Series, I've been exposed to an ad for the Dodge Nitro. Frequently. And I couldn't help but notice some kinematics problems embedded in the ad. The plot is that an ordinary car in need of a jump start is aided by a Dodge Nitro. The Nitro's power overwhelms the ailing car and launches it sky-high. Having gone up, the car eventually comes back down. But only after what can best be described as a "TV ad eternity."

You can watch the commercial here:

Check my math. I have the launch speed of the car at about 100 mph and the apex of the car's flight being about 100 meters above the parking lot asphalt.

Sadly, even with a good estimate of the car's weight (or mass), I cannot hazard a guess as to the launching force. Don't you hate it when that happens?

Sunday, October 22, 2006

So long, Motion and Forces

I'm now done teaching all the standards in Standard Set 1: Motion and Forces. Constant "and" average speed, Newton's laws, circular motion, and gravity--all covered. I might have even snuck in some topics that went beyond the standards.

Me being done teaching motion and forces doesn't mean my students are done learning motion and forces. My unit tests and semester final exam are designed to encourage retention of the academic content. Future unit tests will include questions on motion and forces. The drum beats until the semester comes to a close.

We're now moving on to Standard Set 2: Conservation of Energy and Momentum. That set will be finished well before Winter Break. Heat and Thermodynamics will close out the first semester.

With five standard sets to cover and the exam administered in April, you need to cover three of the five before the end of the first semester. That is, if you aim to cover most of the tested content before the test.

Saturday, October 21, 2006

My district *can* do it right!

My last two posts about the uselessness of the STAR result reports given to teachers by my district got me all worked up. So I wrote a frank missive to my school's STAR administrator, who passed it up/across the food chain to the district person who prepares the reports. She was able to generate exactly the reports I wanted!

Report 1: Standards Performance
Report 2: Student Performance Levels

These reports, especially Report 1, can be used to inform instructional decisions.

My administrator put in an order for reports in these formats for the other teachers at my school.

I'll score it as good news. It knocked a chip off the boulder that is my cynicism.

Saturday, October 14, 2006

STAR data in a useful format

In the previous post (below), I listed the problems with the STAR reports that my district generates for me. Extraordinarily useless. Here's a link that will take you to what I turn that data into. Mind you, it takes time and energy to do this. Anyone with a life wouldn't do it.

STAR Physics/Baird

1. It's a big file, an interactive Quicktime slideshow.
2. The results are pretty good. But me being on third base doesn't mean I hit a triple. I teach at a good school in a good neighborhood. The students generally know why they go to school. And their parents are quick to remind them should they forget. Anyway, the specific numbers aren't the issue here. It's the format of the data and how it's given teachers.

So what do I want from my district? I want to know how the whole group ("cluster") of my physics students performed in each of the six tested standard sets. That's the information that is most useful to me as a classroom teacher. I'd also like to know how many of my physics students performed at the Advanced, Proficient, Basic, Below Basic, and Far Below Basic levels. That info is interesting but not essential. The whole report would require about half a sheet of paper.

School district STAR reports for teachers

Each spring, California public high school students sit for a battery of state-mandated exams. The results are machine-scored and tabulated. Performance levels are set and imposed. Schoolwide reports are generated by the California Department of Education (CDE) and posted on their website by August 15.

The CDE passes then passes districtwide data on to each school district. Each district is charged with generating a report for each teacher, showing how that teacher's students performed on the exams corresponding to the teacher's course. For example, I am to be given a report showing how my students performed on the physics exam. I confess that I am genuinely curious about how my students performed on the exam. I hope that they do well.

The most valuable aspect of the report is that is gives some detail regarding the specific areas of strength and weakness among my students. There are six areas of the physics test for which data is collected: Motion and Force, Energy and Momentum, Heat and Thermodynamics, Waves, Electric and Magnetic Phenomena, and Investigation and Experimentation.

In theory, I could see how my students performed in each of these areas and modify my instruction so as to fortify any areas of relative weakness. Indeed, I interpreted an early report as an indication that I needed to beef up my treatment of electricity and magnetism. In subsequent years, my students have performed better on the exam's electricity and magnetism questions.

The problem is that the teacher report generated by my school district is amazingly useless. It was designed by someone who thought I would find utility in knowing how the 10th-graders in my 1st period class performed on the test, then how the 11th-graders in my 1st period class did, then how the 10th-graders in 2nd period, etc.

To me, such reports are mind-bogglingly useless. Who would want to know any of that? How could it possibly useful to a classroom teacher. "Next year I'm going to strengthen the treatment of heat and thermodynamics for my 4th period sophomores."

I spend a nontrivial amount of time and Excel energy melting down the data provided and reshaping it into a useful report. I'm pretty sure that I'm *the one* who does this at my school. Other teachers have lives.

What I want to know is how my students--all of them--did in the various areas of the test. Not how the 1st period sophomores did and how the 2nd period juniors did and the 3rd period sophomes and 4th period juniors, etc., did. I want all my students pooled together. Maybe I'm just lazy, but I don't differentiate instruction between grade levels or periods.

The report that I want would be much simpler and would require less than one tenth the paper to print.

Is it just me? Does anyone else out there even care? Bueller?

Saturn, backlit

The Bad Astronomer had a post about this image. When I saw it, I stayed up way past my bedtime to fiddle and fuss and made a 13"x19" photo inkjet print of it. Absolutely gwarjiss!

See The Bad Astronomer's post for details of how the photograph was taken. It's not a Photoshop illustration or a manifestation of CGI. But it is evocative of space explosions as envisioned by artists at Industrial Light and Magic. Think Star Trek VI opening scene or Star Wars IV ("Special Edition") Death Star explosion. There is something visually appealing (if not necessarily physics-ly appropriate) about an equatorial ring being thrown radially outward.

Sunday, October 01, 2006

The first law before Sir Isaac

Sorry about the absence. Between moving, a PhyzVan failure, a workshop, moving, a wedding, and moving, the blog had to simmer.

When teaching the concepts and subtleties of inertia and Newton's first law, I like to include some information on the understanding of the first law before the time of Newton. So I include a few relevant historical references.

1. "The cessation of motion is due to the opposing force…. If there is no opposing force…the motion will never stop."

2. "It is impossible to say why a body that has been set in motion in a vacuum should ever come to rest; why, indeed, should it come to rest at one place rather than at another. As a consequence, it will either necessarily stay at rest or, if in motion, will move indefinitely unless some obstacle comes into collision with it."

Both references precede Newton's Principia by about 2000 years.

Reference 1 comes from the Mo Ching, published in China approximately 2400 years ago. The source of reference 2 is a little more shocking.

When posed to groups of physics education professionals, I've never had anyone correctly identify the source. Some guess Newton, others guess Galileo. And these are smart people--many of them much, much smarter than I'll ever be. I'm pretty sure many of them don't believe me when I tell them the source.

The point of the lesson is a fundamental truth stated eloquently by Alfred North Whitehead: "Everything of importance has been said before by someone who did not discover it."