Gratuitous time lapse of this year's exhibit adoption. Special thanks to Britknee for being such an excellent bouncer/door guard.
2014 ExploratoRio Exhibit Adoption
The "season" runs from the close of Presidents' ("Ski") Week until ExploratoRio (Open House). Exhibitors bring their exhibits in to show me that they work. Or I show them how to use school equipment to set up their exhibit (so they'll be able to do it on their own on ExploratoRio Eve). We discuss the operation, logistics, physics, perception.
I schedule one or two exhibits after school each day during the season, with the exception of Thursdays and other known blackout days. (Thursdays are out due to district-mandated "collaboration".) The one-on-one time with each set of exhibitors pays dividends on ExploratoRio Eve and Day in terms of operational smoothness and crisis avoidance.
Support staff positions are filling up nicely. Elementary class hosts are bringing in teacher contact information, and I've laid out a visitation schedule. We have three time slots yet unclaimed (two them being 11:30am-12-30pm). There are times when the space we have gets a bit crowded. We want to get as many elementary class students as we can to come in for a visit, but we have school for only a minimum day, so there is a hard time limit. One solution, I suppose, would be moving ExploratoRio off of Open House. But the original vision of ExploratoRio was for it to be the Open House activity.
Saturday, March 08, 2014
Friday, February 14, 2014
Doing AP science wrong
I've taught AP Physics B since 1986. The course I taught was always intended to be an excellent advanced high school physics course that would compare as favorably as possible to an introductory college physics course. Engaging demonstrations and robust lab work was always important. But in the end, students needed to be prepared for the College Board's Advanced Placement Physics B Examination, administered each May.
From 1986 to 1997, we ran it as a first year course. But it was supposed to be a second year course, and in 1998, we brought our course into alignment with College Board expectations.
In recent years, sign-ups for AP Physics B dwindled at my school. Not so for AP Biology. Nor for AP Chemistry (which is a harder test than AP Physics B, as far as I'm concerned). Last year we introduced AP Environmental Science. It blossomed from one section last year to two this year. Impressive growth. While AP Bio and AP Chem held there ground, AP Physics bit the proverbial dust. Enrollment for 2014 did not merit a single section.
It was hard to observe the demise without concluding that the instructor of the course (that would be me) was doing something wrong. Data provided by the school's administration today sheds light on the subject.
In 2013, I had 25 students in AP Physics B. Only 21 sat for the exam, an unusually low test rate for me. Still though, while 16 of my students earned an A or B in my class, 16 also earned a 5 or a 4 on the exam. Six of the 21 AP Physics B examinees earned 5s. All my examinees passed with a 3 or better. I am rightfully very proud of all of them.
[sanctimony]
What I didn't know until today was that my raw number of 16 4s and 5s represented better top-tier performance than was had in any other AP science course at my school (including one with over double my enrollment). Or that my six 5s outnumbered the 5s from all our other AP sciences combined.
I also didn't know that my rate of classroom grades of A and B (64%) was—by far—the lowest rate, as was my A rate (under 50%).
[/sanctimony]
AP and honors courses enjoy weighted grading in my district, so an A gets you a grade point of 5, a B a 4, and a C a 3. Where I grew up, a GPA of 4.0 was the mark of academic perfection. My students routinely have GPAs well above 4.2. Students hoping for admission to elite post-secondary institutions are keen to fly their GPAs into the stratosphere. Such students try to enroll in as many APs as possible. But with so many demands on their time (and many are in our nationally-recognized band program), meeting the academic rigor of an AP science course can be challenging.
The story of my AP Physics B's demise can be found in the data that follows. To me, the tale jumps right off the page. If it doesn't to you, interpret that as me overreacting; making a mountain out of a molehill.
The diminishing enrollment in my course amid the flourishing enrollments of my colleague's courses does suggest that someone is doing AP science wrong.
Here's the data:
So...
In AP Physics B, there were 11 As and 6 5s. There was insufficient enrollment to run the course in 2014.
In non-physics AP sciences, there were 82 As and 3 5s. Enrollments in these courses increased in 2014.
A riddle wrapped in a mystery inside an enigma? I think not.
UPDATE: Is it important that course grades given by high school teachers be accurate and valid? Very much so. Colleges are increasingly valuing classroom grades over SAT/ACT scores.
From 1986 to 1997, we ran it as a first year course. But it was supposed to be a second year course, and in 1998, we brought our course into alignment with College Board expectations.
In recent years, sign-ups for AP Physics B dwindled at my school. Not so for AP Biology. Nor for AP Chemistry (which is a harder test than AP Physics B, as far as I'm concerned). Last year we introduced AP Environmental Science. It blossomed from one section last year to two this year. Impressive growth. While AP Bio and AP Chem held there ground, AP Physics bit the proverbial dust. Enrollment for 2014 did not merit a single section.
It was hard to observe the demise without concluding that the instructor of the course (that would be me) was doing something wrong. Data provided by the school's administration today sheds light on the subject.
In 2013, I had 25 students in AP Physics B. Only 21 sat for the exam, an unusually low test rate for me. Still though, while 16 of my students earned an A or B in my class, 16 also earned a 5 or a 4 on the exam. Six of the 21 AP Physics B examinees earned 5s. All my examinees passed with a 3 or better. I am rightfully very proud of all of them.
[sanctimony]
What I didn't know until today was that my raw number of 16 4s and 5s represented better top-tier performance than was had in any other AP science course at my school (including one with over double my enrollment). Or that my six 5s outnumbered the 5s from all our other AP sciences combined.
I also didn't know that my rate of classroom grades of A and B (64%) was—by far—the lowest rate, as was my A rate (under 50%).
[/sanctimony]
AP and honors courses enjoy weighted grading in my district, so an A gets you a grade point of 5, a B a 4, and a C a 3. Where I grew up, a GPA of 4.0 was the mark of academic perfection. My students routinely have GPAs well above 4.2. Students hoping for admission to elite post-secondary institutions are keen to fly their GPAs into the stratosphere. Such students try to enroll in as many APs as possible. But with so many demands on their time (and many are in our nationally-recognized band program), meeting the academic rigor of an AP science course can be challenging.
The story of my AP Physics B's demise can be found in the data that follows. To me, the tale jumps right off the page. If it doesn't to you, interpret that as me overreacting; making a mountain out of a molehill.
The diminishing enrollment in my course amid the flourishing enrollments of my colleague's courses does suggest that someone is doing AP science wrong.
Here's the data:
So...
In AP Physics B, there were 11 As and 6 5s. There was insufficient enrollment to run the course in 2014.
In non-physics AP sciences, there were 82 As and 3 5s. Enrollments in these courses increased in 2014.
A riddle wrapped in a mystery inside an enigma? I think not.
UPDATE: Is it important that course grades given by high school teachers be accurate and valid? Very much so. Colleges are increasingly valuing classroom grades over SAT/ACT scores.
Scientist Valentines: The Movie
Physics teaching colleague, Alex McKale of Stanford OHS, has turned the Scientist Valentines into a video, complete with a lovely physics-song soundtrack. Check it out!
Physics Valentines
Physics Valentines
Tuesday, February 11, 2014
It broke yesterday, and they don't really make them anymore
I use it nearly everyday at school for one reason or another. It comes in handy in a pinch. Mine was a gift from Paul Hewitt when he was moving out of his residence in San Francisco in 2003. He had used it for years, and I used it for a decade beyond that. (And I'm pretty sure I used it more heavily than he did.) It ran through consumables at a reasonable rate, but procuring them when needed was never a problem.
But it stopped functioning correctly yesterday, and it will be difficult to purchase a replacement. When I got it, replacement would have been a simple matter of a visit to OfficeDepot or OfficeMax. But this device appears no longer to be made. Market forces have driven this species to extinction in the past few years.
What was it?
It wasn't an electronic wastebasket. No, those things occupy a substantial amount of space at the big box office supply chains. I'd have my choice from dozens of models if it were an electronic wastebasket that I needed. Electronic wastebaskets are big right now, and the segment appears to be growing. There is a bonanza in electronic wastebaskets. Feel bad that you didn't get in on the ground floor.
It wasn't an adding machine. No, those seem to be doing just fine. If my adding machine went down, I'd have models to choose from on the shelf in the store today. The adding machine is far from obsolete.
The land-line telephone? No. Those are available in every shape and size. Land-line phones command considerable shelf space these days.
Fax machine? The 1980s live on! If I were in the market for a new fax machine, I'd have to comparison shop between multiple competing models.
Digital frame? You thought they were gone, but there are still models to be found on the shelves at OfficeDepot. Note the electronic wastebaskets nearby. This was a standalone display, more than 30 yards away from the main electronic wastebasket show space. It's quite clear that if you don't have an electronic wastebasket, you really must get one. The selection available on the showroom floor is breathtaking.
Was it my typewriter ribbon? No. The stock of typewriter (and printer) ribbons is well maintained at the modern office supply chain. I will include a link to the Wikipedia entry on typewriter ribbon for the benefit of my younger readers.
No. The long-laboring device whose utility has not yet diminished from my daily life is the personal photocopier. Paul Hewitt gave me a well used Canon PC740 in 2003, and I used it well until yesterday. Yesterday it made a plastic gear-gnashing sound upon power-up. It made several good copies before fading to black. Literally. The copies it made in the midst of a run got darker until the machine produced only toner-filled black tiles. The scanning tube remains as bright as ever, but black is all that comes out.
You can argue that the era of photocopying is over. Today's documents are electronic. Paper is the past!
But don't tell that to the stores that no longer sell personal photocopiers. Substantial volumes of these warehouse stores are devoted to photocopying services.
And don't tell that to school teachers. The photocopier is the most heavily used piece of office equipment at the school. We've never had fewer than two high-volume machines on campus, with low-volume units spread hither and yon.
I suppose I'm just having an Andy Rooney ("This modern world of yours is crazy!") moment. Perhaps I'm simply jarred because the predicament was unexpected. I used the machine and expected to buy a replacement when it died. But I can't. At least not easily.
The invisible hand of the market is telling me, in no uncertain terms, that I would be wrong to want a personal photocopier. The device is not useful in today's world. Not like typewriter ribbons, digital frames, adding machines, fax machines, and land-line phones. Those things are now! They are the U2s of office machines. Personal copiers? Destiny's Child.
I know there is no arguing with the flawless reasoning of The Market. I'm just too dumb to know why I can't readily buy a photocopier, but there is no end to suppliers eager to sell me toner for a long-since discontinued photocopier.
What I clearly need to do is to replace my broken copier with today's office machinery rock star: the electronic wastebasket. It is clearly the Bruno Mars of productivity devices; it could literally shred the gnar!
But it stopped functioning correctly yesterday, and it will be difficult to purchase a replacement. When I got it, replacement would have been a simple matter of a visit to OfficeDepot or OfficeMax. But this device appears no longer to be made. Market forces have driven this species to extinction in the past few years.
What was it?
It wasn't an electronic wastebasket. No, those things occupy a substantial amount of space at the big box office supply chains. I'd have my choice from dozens of models if it were an electronic wastebasket that I needed. Electronic wastebaskets are big right now, and the segment appears to be growing. There is a bonanza in electronic wastebaskets. Feel bad that you didn't get in on the ground floor.
It wasn't an adding machine. No, those seem to be doing just fine. If my adding machine went down, I'd have models to choose from on the shelf in the store today. The adding machine is far from obsolete.
The land-line telephone? No. Those are available in every shape and size. Land-line phones command considerable shelf space these days.
Fax machine? The 1980s live on! If I were in the market for a new fax machine, I'd have to comparison shop between multiple competing models.
Digital frame? You thought they were gone, but there are still models to be found on the shelves at OfficeDepot. Note the electronic wastebaskets nearby. This was a standalone display, more than 30 yards away from the main electronic wastebasket show space. It's quite clear that if you don't have an electronic wastebasket, you really must get one. The selection available on the showroom floor is breathtaking.
Was it my typewriter ribbon? No. The stock of typewriter (and printer) ribbons is well maintained at the modern office supply chain. I will include a link to the Wikipedia entry on typewriter ribbon for the benefit of my younger readers.
No. The long-laboring device whose utility has not yet diminished from my daily life is the personal photocopier. Paul Hewitt gave me a well used Canon PC740 in 2003, and I used it well until yesterday. Yesterday it made a plastic gear-gnashing sound upon power-up. It made several good copies before fading to black. Literally. The copies it made in the midst of a run got darker until the machine produced only toner-filled black tiles. The scanning tube remains as bright as ever, but black is all that comes out.
You can argue that the era of photocopying is over. Today's documents are electronic. Paper is the past!
But don't tell that to the stores that no longer sell personal photocopiers. Substantial volumes of these warehouse stores are devoted to photocopying services.
And don't tell that to school teachers. The photocopier is the most heavily used piece of office equipment at the school. We've never had fewer than two high-volume machines on campus, with low-volume units spread hither and yon.
I suppose I'm just having an Andy Rooney ("This modern world of yours is crazy!") moment. Perhaps I'm simply jarred because the predicament was unexpected. I used the machine and expected to buy a replacement when it died. But I can't. At least not easily.
The invisible hand of the market is telling me, in no uncertain terms, that I would be wrong to want a personal photocopier. The device is not useful in today's world. Not like typewriter ribbons, digital frames, adding machines, fax machines, and land-line phones. Those things are now! They are the U2s of office machines. Personal copiers? Destiny's Child.
I know there is no arguing with the flawless reasoning of The Market. I'm just too dumb to know why I can't readily buy a photocopier, but there is no end to suppliers eager to sell me toner for a long-since discontinued photocopier.
What I clearly need to do is to replace my broken copier with today's office machinery rock star: the electronic wastebasket. It is clearly the Bruno Mars of productivity devices; it could literally shred the gnar!
Friday, January 31, 2014
Faraday Cage: AM vs. FM
To demonstrate the fact that electric fields (unlike gravitational fields) can be shielded, I have taken to showing the effects of a Faraday cage on radio signals. (I wonder how many more years I'll be able to perform this demonstration this way.) I use a transistor radio as my "field detector" and a metal colander and a metal splatter screen as my blockers.
In serendipitous monkeying around, I noticed that FM signals "behave" better for this demonstration than AM signals do.
The FM seems impervious to being placed on the screen or in the colander. But when encapsulated, it virtually drops to nothing.
The AM signal, on the other hand, is sensitive to being placed in the screen or in the colander. But the signal remains intelligible even when the radio is fully encapsulated.
Take a look.
Faraday Cage AM FM
In serendipitous monkeying around, I noticed that FM signals "behave" better for this demonstration than AM signals do.
The FM seems impervious to being placed on the screen or in the colander. But when encapsulated, it virtually drops to nothing.
The AM signal, on the other hand, is sensitive to being placed in the screen or in the colander. But the signal remains intelligible even when the radio is fully encapsulated.
Take a look.
Faraday Cage AM FM
ExploratoRio 2014: The 20th Anniversary Begins
Today the exhibit recipes were posted. I plan to adopt them out prior to the Presidents' Week break.
ExploratoRio 2014 Exhibit Recipes Posted
For more on ExploratoRio, see
ExploratoRio Resources.
ExploratoRio 2014 Exhibit Recipes Posted
For more on ExploratoRio, see
ExploratoRio Resources.
Monday, January 20, 2014
Evidence of ball lightning published in PRL
Physical Review Letters has published the work of Chinese scientists who appear to have recorded an instance of ball lightning.
Ball Lightning
Chinese scientists have recorded the rare phenomenon in nature for the first time
Here's a quick review of ball lightning.
And the video (with spectrometer image).
First recorded scientific video of Ball Lightning
Ball Lightning
Chinese scientists have recorded the rare phenomenon in nature for the first time
Here's a quick review of ball lightning.
And the video (with spectrometer image).
First recorded scientific video of Ball Lightning
Thursday, January 16, 2014
Balanced Balloons - a new Figuring Physics
I am delighted to have developed some "Figuring Physics" ideas for The Physics Teacher columnist, Paul Hewitt over the years.
If you want a treasure-trove of Hewitt's "Figuring Physics" (a.k.a. "Next-Time Questions"), you're in luck.
Hewitt's Next-Time Questions at Arbor Scientific
We're in the midst of our study of electrostatics. Usually this brings torrents of rain to Northern California. This year's drought seems to be impervious to my machinations.
In any case, this little puzzle came to mind. It was preceded by the developments of Balancing Charges 1 and Balancing Charges 2 PhyzJobs. But I turned the concept into a standalone puzzle.
We begin with two helium-filled balloons that, when oppositely charged, are exactly balanced. They are attached to a massless bar that has a frictionless hinge at its midpoint.
I'll post the answer in the comments next week. It's a fun one to think through. Maybe it will make the cut for next year's round of "Figuring Physics."
If you want a treasure-trove of Hewitt's "Figuring Physics" (a.k.a. "Next-Time Questions"), you're in luck.
Hewitt's Next-Time Questions at Arbor Scientific
We're in the midst of our study of electrostatics. Usually this brings torrents of rain to Northern California. This year's drought seems to be impervious to my machinations.
In any case, this little puzzle came to mind. It was preceded by the developments of Balancing Charges 1 and Balancing Charges 2 PhyzJobs. But I turned the concept into a standalone puzzle.
We begin with two helium-filled balloons that, when oppositely charged, are exactly balanced. They are attached to a massless bar that has a frictionless hinge at its midpoint.
I'll post the answer in the comments next week. It's a fun one to think through. Maybe it will make the cut for next year's round of "Figuring Physics."
Dan Burns updated his Science on The Simpsons page
From Dan:"Hello Science on the Simpsons fans, I have added 13 more clips to the website. I included more biology related ones so share it with your life-science colleagues. Don't worry, there are some new physics ones like "Faster than Sound" and "Black Hole 1 and 2". The new clips start with "Acid Rain" in the right column:
Science on The Simpsons
Remember these are for educational purposes only.
Dan Burns
Los Gatos High School"
Go take a look. But be warned, you may find yourself binge-viewing the clips!
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