The big bang as mythology

For all the noise about Darwin's descent with modification, a deep understanding of evolution provides a delightful way to hold together just about everything we know in biology without referring to supernatural concepts.

(In my best sotto voce I will happily admit that evolution does not help us at all in grasping how life came to be, and that the cell theory's weakness is that it cannot explain the original cell.)

You don't need to "believe in it"--there's no leap of faith needed--it works well, and unless some as yet fantastic empirical data gets revealed, it's not going to need major tweaking.

(Again in my sotto voce, I gleefully admit such unimaginably fantastic observations may indeed arise, which is why science is so much fun!)

Meanwhile, kids get drilled on the Big Bang Theory with little complaint in these parts, a model which purports to explain the origins of our universe (or at least everything since after the first 30 seconds, when the universe got to be a few millimeters in diameter, which, of course, makes no sense without a reference).

Look in a textbook and read about it--about 14 billion years ago or so (give or take a billion here or there), the universe was a singularity, a point. Something happened--and space started to expand, to exist.

Too many times I have seen this pictured as an explosion--the event is being viewed from the outside by the illustrator. The textbook I've used the past three years has a picture of an explosion among the stars:

The big bang theory says that 12 to 15 billion years ago, an event called the big bang sent matter in all directions. This matter eventually formed the galaxies and planets.

(Holt Science and Technology: Physical Science, 2006, p. 21)

Big problem--there was no outside, there were no directions-- at least according to the model. So who is looking at the "explosion"? God?

The model too often gets oversimplified, taught by folks with insufficient understanding (and I put myself in that category), and as a result we create myths instead of a scientific model.

When viewed this way, the Big Bang model becomes a religious one. Yes, I know the picture is just to help students imagine the event, and yes, I know that the textbooks are not pushing the God thing, but the result is the same. It's bad science.

What do I do? I hedge.

If we accept that the universe is expanding (and we do little in class to show this is so), then it makes sense to think that the universe was "smaller" or "more dense" in the past.

And that's as far as I can take it with "low level" freshmen, without getting into religious (by my understanding) grounds. My kids may leave 9th grade knowing a little less about the common scientific myths we thrust on 14 year old children in our schools, but I think they might have a better grasp on what science means.

I am a science teacher--I teach science.

The artwork is from NASA.

I teach ancient Greek philosophers

It finally hit me--high school freshmen think like ancient Greek philosophers.

In Period 1 history class, the students are told that ancient Greece is the birthplace of western civilization; by Period 4 science, they're being told that their Aristotelian views of the universe are silly.

No wonder the kids resist science.

A few nuggets of ancient Greek wisdom:

We can see in absolute dark.

Objects emit particles that are detected even in the dark. Democritus believed objects emitted eidola, replicas of the object an atom thick, that hit the eye.

I suggested to one class that they spend some time in a totally dark closet. One student said he didn't need to, he knew he could see in total darkness. Reason over observation--if Aristotle could reject experimentation over pure thought, well, can hardly blame a child for thinking the same thing.

When was the last time you put yourself in absolute darkness. Are you sure you cannot see in the dark?

The sun is a big, hot rock.

If it's good enough for Anaxagoras, it's good enough for my students. The stars are also rocks, but are so far away you cannot feel their warmth.

So now instead of debating what I once considered a foolish point with Sergio or Briana or Louis as they fumble with their iPods and phones, I pretend I am talking to Anaxagoras.

Try explaining plasma and nuclear fusion to an ancient Greek philosopher, a very bright one at that.

Imagine inviting Anaxagoras to dinner. Most of us would use the finest china, serve filet of mignon and the best wine, and only after some initial small talk even consider questioning his position. We'd give him lots of latitude (for how can we expect him to grasp modern physics) and give him room to stumble. He announces at dinner that the sun is, indeed,"a red, hot stone."

Now imagine a 14 year old child who says the same thing in class--there'd be laughter by students, an eye-roll from the teacher.

Until someone offers evidence otherwise, I think a 14-year-old who thinks the sun is a hot rock has good reasons for believing it. It's not our job to convince him otherwise; it's our job to show him how we came to our current understanding through the available evidence. (This translates into getting the right answer on a multiple choice question, true, but I can dream.)

Reading it in a textbook is not a good reason to believe something.

Heavy objects fall faster than light objects

Imagine Aristotle in your class--he's getting to be a real thorn in your side. He says heavy objects fall faster than lighter objects.

Heavy objects are made of "earth" (one of the 4 basic elements), and the object's natural place is back in the earth. Take a big chunk of earth away from its proper place--it needs to return. Do you have a better idea, Mr. Teacher?

How many of us would retort with "Did you read your assignment last night, Ari?" You have a 24 children in class, you have standardized tests breathing down your neck, why won't Aristotle comply?

Oh, well, that's different--he's from ancient Greece, we're more sophisticated now, everybody knows that gravity is this force that no one understands that causes every object in the universe to be attracted to every other object in the universe.

Imagine a thinking 14-year-old student weighing between a simple Aristotelian version of gravity that says heavy things fall faster because they want to return to their proper place against the teacher version that's telling you that a star millions of light years away exerts a slight pull on you.

The same teacher, by the way, who just told you astrology is nonsense. Even though you had good luck last Friday, just as your horoscope predicted you would.

So I drop my keys and paper clips and lab stools and heavy science books in class--and we all marvel that they hit the ground at the same time. It amazes me every time. I've been dropping things for almost 50 years, and after a few decades I finally accept that at low velocity many objects do in fact drop at the same rate.

I expect my kids to unlearn ancient Greek physics in less than a class period. Took western science about 2000 years to unlearn the same concept (thank you, Galileo).

***

Teaching my lambs does not get any easier realizing that their reasoning rivals that of historic geniuses. Does make me a little more patient, though.

The drawing is of Anaxagoras--the writing is loosely translated as "A classroom full of Anaxagorases"

"I am a molecule, I cannot stop moving..."

Occasionally I'll bounce around the room, muttering "I am a molecule, I cannot stop moving." I'll walk until I hit something, anything, then ricochet in some reasonable approximation of a billiard ball, eventually bumping into something else. Sometimes I get wedged between two rows of desks, vibrating like a pinball stuck on a bumper.

It makes the kids nervous. Doesn't help that I use my robot voice. I AM A MOLECULE I CANNOT STOP MOVING I AM A MOLECULE I CANNOT STOP MOVING I AM...

If I am feeling particularly brave, I get the students out of their seats, cram them in a corner of the room, then ask them to all do what I was doing. Chaos ensues, but within a minute or two, you have fairly random dispersion of the human molecules (except for the 3 or 4 males chasing Polly McMuffin), and I ask them to freeze.

I ask the lambs to look around--how did the particles get so spread out?

If I am feeling maniacally brave, I repeat the exercise, but now walk around with a lit candle, asking the students what they would do if they were heated up a bit. (Yes, I felt maniacally brave once, and hope not to feel so brave again, at least not until tenured.)

If I am feeling not so brave, I'll dilute a drop of milk in water, and have the kids look at it under a microscope. Once the fat droplets settle down, they wiggle and jiggle about, reflecting Brownian motion. Evidence of molecules in motion.

I know someone is thinking when a voice rises above the chaos--"but why do molecules keep moving?"

I can give a fancy pants answer, mumbling about the kinetic theory of matter, but when you push the issue, no one really knows. It wasn't that long ago that physicists argued whether molecules truly keep moving. Boltzmann, a prominent physicist pushing the idea that they do, committed suicide. I'm a passionate teacher, but I draw the line.

So in my best science teacher voice I say:

Beats me!

Students don't like that answer. I give the same answer when they ask why gravity acts the way it does (perhaps better phrased as why does mass act the way it does, but hey, these are freshmen).

Most just figure I'm clueless, but when surrounded by kids who have been told they're a bit slow enough times to start believing it, some find comfort that some things just aren't known, even by teachers.

If they only knew how true that is....


The "I am a molecule" routine was taught to me by Ms. Maria Rinaldi, my cooperating teacher back when I was still in the embryonic stage of pedagogy. I got a million dollar education from her.

First day of school, physical science (freshmen)

Opening day is usually chaotic, nothing new there. We're implementing a new scheduling system designed by a company that has "years of exerpeince" and, well, it shows. Still, once the kids are in the room, once attendance is taken and the procedures reviewed, good things happen.

***

I simultaneously dropped a paper clip and my set of keys (like most floats my key ring rivals that of a warden). The kids predict what they think will happen, then note what actually does.

The knot of keys and the paper clip hit the ground at the same time. Really. Try it.

Five minutes later I asked a student which hit the ground first.

The paper clip.

"Why do you think that?"

Cuz that's what you said.

Pretty sure I didn't, but I don't argue the point.
"Which one did you see hit the ground first?"

They both hit at the same time.

In school, you succeed for producing the "correct" answer, which doesn't always coincide with the right one. If the child heard me say the paper clip hit first, that's his answer, even if he observed otherwise.

It's a tough habit to break. In the long run, he might even be better off picking the authoritative "correct" answer even when he can see otherwise.

Why does teaching science matter then?

With science, a child has a framework to challenge dogma. It's not enough to say challenge authority; you need to give the children tools. It's easy to create cranks with tinfoil hats, much harder to create critical thinkers.

What's matter?

I start off my physical science class with the usual introductions, procedures and such, but before the first day is over, I tell them that by the end of the year they won't even know what "stuff" is anymore.

"Stuff" is as good a definition of matter as you are going to get at 9th grade, and it's probably as good as you're going to get for most of us without degrees in physics.

The kids look at me quizzically, I gawk back, and away we go!

***

"Stuff" ends up being circular. We can get fancy and call it matter, and the text will tell you that matter is anything with mass that takes up space.

Seems that just about any type of mass a 9th grader is going to run into takes up space, and just about anything that takes up space will have mass.

(OK, OK, bear with me--think about the definitions as presented to our students. Newtonian physics starts with a deceptively simple definition of matter. Teachers fall into the same trap as the students, but if we cannot get the kids curious about what we mean by "stuff", the rest of physics is just a dog and pony show.)

Eventually (months later) we will get to inertia, an operational definition of mass (and again a bit circular), but on the first day of class, the kids are pretty smug about what they know.

OK, Mister Dr. D, matter is "stuff"--we got that, everyone knows what "stuff" is.
So that's it? that's all we gotta know today?

Before I go any further, I tell them that if I do my job, by the end of the year they won't even know what "stuff" is anymore. And more important, they'll know they don't know.

Ah, grasshopper!

***

"So what's mass?"

I'm not looking for a post-doctoral account here, but I don't want to cheat the kids, either.

So I push the issue, even on the first day of class.

If you want someone to learn science, you must first shake them off the ledge of certainty, or rather, convince them they want to jump.

***

OK, so what is it, Mister Dr. D?

I shrug, palms up....Kids don't like it when teachers feign ignorance. They hate it when they realize the teacher isn't faking. A few get mad.

Why we gotta learn this stuff if you don't even know what you're talking about?

I was surprised the first time I saw the anger--I welcome it now.

***

Before the end of the period, I'll review what they know about atoms, or rather, review their misconceptions.

This year I'll show them this model, then take then out to the hall with a grain of sand representing the nucleus of an atom. How far would the electrons roam?

I'll let them walk around. Then tell them to walk farther still. I must have been in a summer daydream--yes, we'll do the walk-through, but not on day one.

I then tell them that if the nucleus was the size of a grain of sand, then the atom would be the size of a football stadium.

(OK, I haven't done the calculations myself yet, not to mention that I have no clue what the standard football stadium size is. A high school stadium? Giants Stadium? OK, so I need to go back to the chalkboard.)

***

OK, we got two minutes left now, and I need closure. Shoot, I forgot to hand out the texts. Closure...closure...closure.

This is when I need to keep my mouth shut. A good lesson in general.

Now the children are really squirming. The teacher is an idiot, and now he's standing up there speechless. They can't take the pressure.

Uh, that means stuff is mostly space, right?

I smile. And it's nowhere near winter break yet.

Why I Teach: modeling atoms

I teach physical science. Officially it's Precollege Preparatory Physical Science now, was Integrated Science 1 last year, and Career Options the year before that. I should start a pool on what it will be called next year.

It's really just science for freshman who have no academic aspirations, science for the "low levels." ("Just science" is the best kind.)

Two years ago I had two brilliant students in the inclusion class. Their minds moved far faster than mine, and faster than can be tolerated in a public school setting. If either survives high school, they will do fine, and I suspect they will do fine even if neither graduates.

Atoms are mostly space. We say this, but it's mostly words to students, words they will memorize long enough to fill in a bubble with a Number 2 pencil, then forget. This kind of ability will get you far today, as long as no wisdom is required (and it rarely is).

The classic textbook diagram misrepresents the space--the book would have to be the size of a football field to do the atom justice. It's also a generation or two removed from the electron cloud model (never mind quantum field theory). I learned to be careful when discussing pictures of models--some children get upset when they learn that the book "tells lies."

Science is stories framed within empiricism.

I took the class into the hallway to get a sense of how much space is in an atom. I used a wheat berry as the nucleus. Several students volunteered to carry electrons. Each was given a grain of sand from a beach in Cape May, sent to me by my cousin when sister died. I told the class this.

My electrons were buzzing around the hallway--every now and again I needed to remind a sleepy student to keep moving. We needed about 150 feet, but the hallway was too short. Still, 100 feet between a wheat berry and a grain of sand leaves a lot of space.

The brightest child in class grasped his head and asked me to stop. "This can't be science!" It was too much for him.

This is why I teach.