Faith Hill and Physics

Today we were talking circular motion in class.  I am alway careful to define the confusing words centrifugal and centripetal in terms of their Greek origins (center fleeing vs. center seeking).  Then, I point out a pet peeve: that the 'words' centripical and centrifical do not exist!  I always claim that people use these non-words to hedge their bets since they don't know if something is centripetal or centrifugal.

Today, student SH exclaimed:  "So Faith Hill is wrong!?"  To my perplexed look, she said "You know, that song "This kiss This kiss"?`  So we did a quick internet search and, indeed, it appears that Ms. Hill does say "centripical motion".  She also says that it's like "perpetual bliss" and we all know that perpetual motion is doomed to fail eventually.  Hey!  What is she saying in this song?  Starting to get suspicious about the nature of the song, I scanned the lyrics more closely and found that it's "impossible", "criminal", and "unsinkable".  Only now do I remember that, just like the movie Titanic, country music is supposed to be bittersweet...

Irene cautioned me against using any old site for lyrical content, so (surprise surprise), it turns out various sites will say the Faith Hill lyric is "centrifugal" (a real word but doesn't really fit with the song) but it sounds like "centripical" to me when I listen to the video!

I ended the class singing "You Spin Me Round" much to the amusement of several students...

Fighting the Wrong Fight

We've been dissecting projectile motion problems lately in class.  I have, for years now, been trying to clarify and simplify the thinking process for my students.  Still, some struggle mightily.  I have always assumed that the vector nature of velocity and the algebra of the equations of motion are the sources of trouble for the students.

I have been reading Knight's book on teaching physics and I now think that the issue may be far simpler:  Most people don't believe in Newton's Laws.  Students frequently worry about forces applied during the launching of the projectile and what happens to the projectile after it hits the ground.  (Always confused about "initial" conditions and "final" conditions.)    I think they are uncomfortable with the fact that the means by which the projectile is launched is irrelevant - how it is brought to a stop is irrelevant  -gravity is irrelevant to the horizontal motion - fast things are accelerating just as much as slow things, etc... 

Laws are memorized, equations are manipulated, and answers are obtained - but most people do not change the way they think things work. 

I saw some students at other times of the day and made some terrible analogies based on what they were doing at the time:

1) A student working on his music composition theory homework:  "Think of the bass cleff as the horizontal motion and the treble cleff as the vertical motion: same rules but slightly different roles."  (nervous laughter followed by eye rolling) 

2) A student talking over a recent paper on Thoreau with her English teacher:  "Forget what society tells us about the projectile, let's go back to nature and see what is really going on with that parabola."  (English teacher waiting patiently for me to leave room; student remarks that I should blog this incident)

3) A student engaged in a deep philosphical discussion on the meaning of life:  How far you go is a combination of how much time you have (Vy) and the amount forward thinking you engage in (Vx), but one comes at the expense of the other since you only have so much launch speed to spend. (ok, I completely made this one up but I couldn't resist another plug for Balance)

Push vs. Pull

I am a 20th century creature.  I thought of my blog as a public diary - a place where other interested people may come upon occasion to see what I've been thinking about.  Turns out that one of my students last year started a facebook fan page for me.  I don't facebook myself but Irene does and when she leaves herself logged in, I confess to checking the fan page to see which former and current students & friends have shown up there.

So, recently (some of you are probably reading this post via facebook), the facebook fan page has been pulling content from this blog and pushing it out into the facebook world.  Some of you have been spammed by these posts (I am wearing an especially cool sweater and striking a fancy pose in my facebook fan picture) and I have mixed feelings about this.  In principle, I don't mind but I just hope the pushing of blog content doesn't change my postings (ooops - it just did!). 

I just checked one of my earliest blog entries, and  I do feel that having a forum to write my thoughts down has been a positive thing.  Writing down thoughts requires more discipline than simply thinking them and knowing others may read them forces a certain integrity in process that I would not impose on myself otherwise.  So, hooray for blogging and the 21st century!

In this 21st century, everything is tracked and google analytics tells me that over 450 people have taken a look at the site for an average of 2.2  minutes per visit since I started the blog last June (2009). 

Here is a pie chart generated by google to show the breakdown by network location of the visitors (who knew they could do that?) (Wayland Public Schools is the 7th most popular provider - hmmm....)

Western Red Persimmon or Foreign Eggplant?

The other night, my father-in-law mentioned that in Chinese a tomato is a "fān qié" which means "foreign eggplant". Finding this very interesting, I mentioned it in a class with two Chinese speakers.  The Cantonese speaker agreed, but the Mandarin speaker disagreed calling it "xī hóng shì" which means "western red persimmon". 

Hmmm.... I was very confused since I know that my wife's family is Mandarin speaking.  It turns out that this is a difference in mainland China vs. the more western-influenced Taiwanese Chinese.

What is a tomato to me is a foreign eggplant in Taiwan and is a western red persimmon in mainland China. 

But, it's all good, because the original word in the New World meant "wolf peach" anyway...
(if you want to learn where we got our word tomato from, refer to my old post about turkeys)

Thanksgiving in Corsica

A blast from the past:
What follows is a cut-and-paste from an email I wrote some friends in November of 1998 while I was in France working with my aunt and uncle in the winery: (believe it or not, it is all true)

So somehow, at some point, the French relatives got the idea that I was going to prepare an authentic Thanksgiving dinner (seeing as how I was staying so late into the year this time). I wisely prepared my escape by discretely announcing my date of departure from Corsica as November 26. I thought I had it made until a week ago when my Aunt tells me, "Since your cousin is coming home next weekend and you'll be leaving the day before Thanksgiving, why don't we celebrate it early - say this weekend. Oh, I'm inviting my parents too"

Oh, great!  My thanksgiving knowledge consists of which Nouveaux Beaujolais is cheapest this year. So I start sending the pleas for help to my mother:  "Well, you need a big turkey of course" Do Turkeys exist in France? I think it's a new world meat... When I start asking around at the stores here, the response is more or less along the lines of "You mean a WHOLE one?" coupled with those exasperated aren't-you-an-idiot looks that only the French can give. Eventually the best I can find is a frozen, pre-stuffed (I never did understand with what, but it was definitely not cornbread-based which Mom said was a must) turkey weighing a whopping 3.5 pounds. In the same store, I spot a beautiful frozen bird, weighing in around 7 pounds and, best of all, unsullied by any strange French stuffing or sauces! "That's the ONE !" I cry (turns out it was a neutered rooster (is that a violation of the Geneva convention? Is this commonly done in the U.S. and I am simply ignorant?))


Next the quest for cornbread was on. This one turned out to be easier than expected as I found a box of cornmeal in a grocery store sandwiched in between "Authentic American pancake mix" and "Authentic Mexican Salsa Sauce" in the "Strange and Unusual" aisle. The cornbread, avoiding baking like the plague all my life, turns out to be thinner after baking than before. Suspicious, but probably okay since I'm going to break it into small pieces anyway... I felt like things were going awry when my Aunt looked simply horrified when I was roaming through her refrigerator in search of random things to throw into the stuffing, "You mean there's no meat in the stuffing?" I hem, I haw, but quickly remember those pearls of wisdom from my mother ("When dealing with the French, be your most confident when you are at a complete loss"), "Ah, no - you see- the first pilgrims who started this grand tradition were actually vegetarians and they, uh, except for fowl of course, and so an authentic American thanksgiving has no meat. Except for the turkey, or the neutered rooster, as the case may be". She looked mighty suspicious of my explanation, especially after she caught me slipping a little bacon in the stuffing. But, hey, the French do respect a well told twist of the truth when delivered with confidence.

Vegetables, I need vegetables with lots of fall colors. Bake it, puree it, stream it, boil it, whatever- don't know what they were, I just made sure there were plenty of colors in different bowls scattered around the table. Ah, you should have seen me convincing my Uncle that you were supposed to put instant mashed potato flakes in the pureed squash (how was I too know it was going to come out as soup?).  Corn on the cob, I knew, was going to be tough. I sucked up my courage and spent an afternoon chasing down ever more exotic grocery stores; "On the cob? That is for the animals on the farm..." "But I can find it in cans and not just in the dog food aisle!" "Yes, well, that is for summer salads and to be served cold." Finally I was forced to surrender and made some form of something they tell me is called succotash (my version definitely did look like dog food).


My mother, with her intensive studies of southern lifestyle, sends an email with a simple "Fried green tomatoes would be nice."  Now I'm pretty sure my mother has never made fried green tomatoes and she has definitely never served it at any of her 26 thanksgivings I've eaten... but my table is missing some green so I go for it (how was I to know it turns out yellow after you roll it in cornmeal?)

Now I am a big pecan pie fan and I wasn't going to give on this one.  Pecans: Negative, not in season. Corn syrup: Negative, too disgusting to contemplate for the French. I substitute honey and walnuts. As I said, I'm no baker, so I didn't have it in me to fake it when my uncle came to check on me. Being a noble sort and not much of a baker either, he takes one look at my batter and starts adding flour and yeast. This is not good I'm thinking, but he looks so happy I say nothing...The pie winds up rising like a fluffy baker's hat in the oven and, after we cool it down and cut away the burned parts, we're left with something flatter than my cornbread (and with less sugar). I assure him this is normal and that all pecan pies are like this. He shrugs, looks happy and comments "At least it doesn't have corn in it!"


I'm starting to think of the plan of attack for presentation, distraction, running for cover, etc., when my Aunt comes in with a long face and says "My parents can't leave their house, my father's doctor says he is too frail to take the stairs." Okay, now there will only be three disappointed French people tonight. "I was thinking, we could just pack the whole feast into our cars and drive over to their house!" Thank god no one took a photo of my uncle and I slipping a 3/4 baked neutered rooster in an orange crate into the back of his Fiat Punto.


I'm reheating things at the grandparents' pad: in the oven, on the stove, on all the burners, when they start trying to help me "What order do we serve the dishes in?" "What are the traditional predinner drinks and what munchies do you serve with them?" "What's the traditional after dinner drink?" But now I'm on point, I'm in the zone, I can do and say no wrong, and so, effortlessly, the stroke of genius comes forth from my lips, "All at once; American whiskey straight up with lots of popcorn; champagne."


After getting tipsy on the whisky and filling up with heavily salted popcorn, the dinner looked and smelled grand and everyone was happy enough to think they were enjoying it. When I saw the warning signs, "No thanks, you can keep that mashed, puréed succotash thing on your side of the table...", I quickly yanked the dishes off the table and brought out the champagne while cutting the smallest possible slivers of the Honey & Walnut Pecan pie with gobs of vanilla ice cream onto everyone's plate. This technique of serving drinks on empty stomachs and filling everyone up with popcorn was so effective, they are still thanking me! Ha!


Hope you all have a nice, authentic thanksgiving as well next week. I will be leaving Corsica as planned next week, but Thanksgiving has already come and gone in France.


all the best,


Ken

Sir Isaac and His Seven Colors

Lately we've been rockin' out in the Riddy household to They Might Be Giants' "Roy G Biv", and it's got me thinking about Isaac Newton and the rainbows we have inherited from him. 

I say that we have inherited the rainbow from him because our actual viewing of real rainbows is filtered based on our expectations.  We "know" there are seven bands and we have seen them many times in various works of art.  Why seven colors though?  The rainbow is a continuous spectrum from the lowest frequency the eye can detect (red) the highest (violet) so nature has not divided the colors into bands. 

Human eyes, however, can only detect three different frequency bands based on the three cones in our eyes (commonly called Red, Green, Blue, although this is an oversimplification).  All colors are an interpolation of those three signals (remember we are talking physiology here not physics).  Take a good look at this close-up of a rainbow:

I can only make out five uneven bands without sharp borders.  It turns out Newton originally only identified 5 colors: red, yellow, green, blue and violet.  Maybe we see five because we get one for each of our cones plus one each for when two neighboring (frequency-wise) cones are being equally stimulated?  (All three cones equally weighted give us the "color" white, of course). 

So where did Roy G Biv come from?  Newton wanted to make the color spectrum fit with the music spectrum of seven notes (click here for Newon's color wheel with notes attached)!  Ever since, artists dutifully draw their rainbows with seven colors and we convince ourselves that we see seven (since it's a continuous spectrum I imagine you can train yourself to identify many arbitrary number of bands as you want).

Beware the difference between what you think you see and what you actually observe!

Innumeracy, Illiteracy, and the Digital Divide

I have for many years now noted the cultural bias that allows innumeracy to be acceptable ("I don't get math", "I don't know which is smaller 10^-5 or 10⁵") but illiteracy to be shameful ("I can't parse a paragraph", "I don't know the difference between a noun or a verb").  This is best argued by C.P. Snow in his famous "Two Cultures" essay on the acceptable nature of scientific ignorance as compared to the stigma of, for example, not knowing any Shakespeare.  I have for many years felt confident that science and math were on the losing end of some larger culture war. But...

It is true that students these days have very little sense of number.  A lot of it, I think, is due to lack of basic math skills: ask them what 6 x7 is and they will reach for a calcuator.  Why should students "waste" their time memorizing math operations when calculators of all kinds are so readily available?  I always argue that a sense of number is built precisely out of having these basic skills and have always imagined that our culture of "innumeracy is okay" has enabled this behaviour. 

This week I discovered that I am wrong.  My freshmen are taking turns presenting to the class using google doc's presentations.  It turns out there is no spell checker built in.  I have been a fool - it's not that students can't mulitply without computational help: it turns out they can't spell either!  Word processors have done to them what calculators have been doing to them for years.

I wanted numeracy to be raised to the level of literacy.  Instead literacy is being lowered to level of numeracy...

Maybe the digital divide that everyone talks about will not be between those who have access to the technology and those who do not, but rather it will be between those that use the technology as an enabling tool and those that use technology as a blinding crutch.

Origami, Betrand Russell, and Muggings

Tuck-Tuck made an excellent origami shirt out of a dollar bill in class the other day.  After I displayed it to the entire class and commented on what a nice shirt it was, he said it "wasn't real".

I thought tangentially about the money and how it wasn't "real" and just a societal construct.  Some words of Bertrand Russell from years ago came to mind (I wish I could remember which book!) and I paraphrased him (without giving due credit I confess) by saying "It's true the money isn't real - I can't use it for shelter or eat it but I find these people working in stores called cashiers who seem perfectly willing to accept these useless bills in exchange for yummy food and other things I can actually use!"

Writing these words now, I had a flashback to 10th grade health class when we had to take turns doing skits of threatening situations.  My partner and I decided to do a skit on a mugging.  When I threatened him with "his money or his life" (quite menacingly as I recall) he responded with "money?"  I then sighed with exasperation and explained "Yes - money: a modern instrument of exchange designed to replace the ancient system of bartering."

(photo from vintageverity.wordpress.com)