Search results matching tags 'teaching science' and 'ignorance'

The electric slide

Anonymous — Sat, 18 Feb 2012 14:32:00 GMT

I occasionally borrow a hand-cranked generator from the physics folks a floor below. It's a very simple device, exquisitely crafted by someone likely dead now. It should work well for another hundred years.

It's simple, and makes the concept of "generating" electricity accessible. If you spin a coil of copper inside a magnet, you push electrons. (You do not, of course, create these electrons anymore than you create the magnets or the wire.)

If you put some resistance in the path of these electrons, say, a light bulb, you need to crank much harder to spin the coil. Again, you can feel this. You are converting mechanical energy into something that "pushes" back.

It takes a fair amount of force to brighten up a reasonably sized bulb.

If a child learns nothing more than this, that to "create" electricity requires a push, that it's not magic, that you don't get electricity for nothing, she's a step ahead of most adults.

***

When I crank on the generator, I breathe a little harder as my muscle cells are called on to work. My cells burn up organic molecules, breaking down into carbon dioxide, using oxygen to catch the remnants of these molecules, spent electrons, in the depths of my mitochondria.

When I crank on the generator, the concentration of carbon dioxide in my room rises a tiny bit--the same carbon dioxide implicated in global warming.

When I crank on the generator, my muscles warm up a little bit--when I convert chemical energy into mechanical, I am less than 100% efficient. The heat I lose no longer serves me.

When I crank on the generator, I make energy increasingly less useful, energy captured as bonds by plants, now released as mechanical energy by me, so I can see photons emitted from the lamp. It took a bucketload of sunlight to produce a thimble's worth of incandescence.

A young child does not need to know any of this to know that generating electricity requires a push, and that the more electricity you need, the more push you must provide.

***

I remember learning about electric generators--it was a classic mid-20th century 16 mm film, moving images of the Hoover Dam with a sonorous male (always male) voice extolling our country's technological virtues.My brain whirs with the clickety-ckickety of a 1963 projector when I think of dams. Children are that impressionable....

A huge dam with huge turbines generated huge amounts of electricity. Somehow that juice got to the wall. It cost nothing because rivers were meant to be damned.

In junior high, my class visited the Oyster Creek nuclear plant, and again we learned about huge turbines generating huge amounts of electricity, clean energy, so safe school children wander within yards of a nuclear reactor.
.
Turns out most electricity generated in the States comes from burning coal, a process remarkably similar to the way I extracted energy from last night's clams. Oxygen strips off electrons from unstable organic molecules, coal and clams to carbon dioxide and water. I do it in a lot more steps, or else I'd spontaneously combust, but the end result is the same. The universe has smaller, more stable molecules, and useful work can be done.

Either way, something had to put the unstable molecules together in the first place. Both coal and clams rely on the nuclear furnace just under 100 million miles away, both coal and clams rely on plants to do this. You don't get something for nothing in the natural world.

***

This is a Chevy Volt. It is an electric car.

You can plug it into your wall and pretend it's green. Or you can start thinking about where things come from, where things go.

If giant hands holding up the Earth assuage whatever feelings you might have as we plunder the planet, then we get the planet we deserve. Nothing comes from nothing.

GM is depending on your ignorance (and your guilt) to shell out over $30,000 for a car.Before you do, come on by B362, and I'll let you crank on our class generator for a bit.

You're an adult now--time to give up magical thinking.

We can argue about the efficiency of coal-generated generating plants vs. gasoline engines, about the relative costs of charging a car during peak or off hours, about the carbon cost of making huge batteries, about the break point (likely around 80k miles) where a Volt may be greener than your Daddy's Oldsmobile, about the risks and benefits of dams, of nuclear rods, of dams, of wind, of solar, of tidal generators.

And these could be interesting discussions....

If you don't believe in magic

First photo from Old Pinawa self-guided tour online brochiue here

What ales us

Anonymous — Mon, 29 Nov 2010 23:50:00 GMT

"Because when you’re set in your ways, you stay true to yourself."
Coors commercial

I'll give the wealthy Coors family this much. They've managed to sum up the crisis in education, in our culture, and in our experiment in democracy in a succinct piece of propaganda.

And they managed to do this by selling mediocre beer at a premium price.

We don't need no stinkin' schoolin'--we revel in our ignorance.

(And we wonder why less than half of Americans accept evolution, the cornerstone of biology.)

Photo by Steven Rhodes , used under CC, of Joe Rees' neon sculpture.

Diffuson confusion

Anonymous — Fri, 19 Nov 2010 00:26:00 GMT

I used to be able to "teach" the concept of diffusion in less than two periods. I threw in the sucrose solution in dialysis tubing demo, its slowly increasing turgidity eliciting giggles from my larval humans. I even tossed in fart jokes.

Now it takes me a week, or longer.

And for some of my lambs, even two weeks would be too quick.

I may or may not be getting better at teaching, but I am getting better at recognizing ignorance, and it's put a huge dent in my schedule. Life was easier when I thought an exam truly measured understanding.

***

To understand diffusion, you have to know a tad about statistics, a little about kinetics, a thing or two about randomness, a smidgen about molecules, and a lot about energy. You also need a dollop of faith in the laws of thermodynamics.

I am a molecule, I cannot stop moving.

Molecules move. If two molecules are randomly moving across this page, they will mostly be far apart, with an occasional pass close enough to wave hello. If they bump into something (including the other molecule), they change directions.

Why do they move? Ask the cosmologists....they'll sputter some nonsense about singularities and expanding universes. Sometimes a shrug makes as much sense as anything.

I am a molecule, I cannot stop moving.

Molecules drift from a high concentration to a lower concentration. This is a purely statistical, random event. Molecules have no desires, no wants. They just keep bouncing around, have been for about 14 billion years, give or take.

It's why "whoever smelt it, dealt it." It's why chocolate syrup dissolving in milk fascinates me. It's why you don't drown in your own carbon dioxide.

I am a molecule, I cannot stop moving.

Unlike previous years, I did not do the dialysis tubing demo this year. I set out 1 M sucrose solution, beakers, and dialysis tubing, then asked the students to figure out the four possible scenarios using one or the other solution in the tubing and in the beaker.

I explained that the tubing acts like a net--its holes were big enough to let water molecules slip past, but not the much larger sucrose molecules. I reminded them that "sucrose water" held two separate types of molecules--this is not obvious to children who take biology before learning chemistry.

The students then picked one of these scenarios, predicted what would happen, and ran the experiment. A few of the students were angry that I would not tell them specifically what to do. (I did advise a bit--tie the tubing like a balloon, don't fill the tubing all the way to the top, don't punch your partner, the usual.)

After setting up the experiment, I asked the students to tell me which way the water molecules go. (Since they are bouncing around in both pure water and in sucrose solution, water molecules are entering and leaving the dialysis tubing simultaneously, just not at the same rates.)

The result? About 30% of my kids got it--some of them with yelps and huge smiles. I know they got it because I listened as they explained it to other students.

Getting 30% of a class to grasp how diffusion works after almost a week setting up the various facets needed to grasp the concept may seem like an incredible waste of instructional time, and perhaps it is.

Still, 30% getting it after 4 days trumps nobody getting it after two. And those who got it are now ready to tackle membrane physiology.

Stimpy fart pic from A Cartoon Christmas.

Melomel, cosmos, and teaching biology

Anonymous — Sat, 16 Oct 2010 21:21:00 GMT

Yes, I know, same old same old...I write for Leslie.
When I walk, I walk with Leslie.
When I eat, I eat with Leslie.
When I sleep, I sleep with Leslie.
When I share melomel, I share it with Leslie.

This morning I watched a couple of bees trying to suck nectar from pink cosmos flowers. The breeze was topping 25 mph. I suspect the bees were spending more calories than they were getting, but they keep trying to get to the flowers, because that's what bees do.

And now I am writing stories about the bees, because that's what humans do.

And it's all good.

***

I'm drinking peach melomel--peaches from 2009 fermented with honey made from flowers in Michigan. A few dormant yeast rest in the bottom of the bottle, poisoned by the ethanol they created.

I took a walk on the today--October beaches have more carcasses than life. The light is fading, and life fades with it. We forget this when we pal around with modern 21st century humans. Except when we don't, and make a formalized ritual out of dying. Which is OK, I guess, but I think I can manage it on my own. I hope I die under the sun, and I hope I'm alone. But we don't talk about this in polite company.

We started farming about 10,000 years ago. It's why I can sit in a permanent structure sipping wine made from cultured peaches and cultured yeast.

I get a little sad when I reflect on the culture we pretend can be sated. It cannot. I get a little sad when I think about my death, too. Contemplating either, however, reflects an ingrained narcissistic and very human attitude contrary to this life thing.

I never saw a wild thing sorry for itself.
A small bird will drop frozen dead from a bough
Without ever having felt sorry for itself.

-- D.H. Lawrence

***

I like being outside. Even when I think I won't, I always do. I have never regretted a single moment outside. And yet I teach my lambs inside.

I like walking barefoot. I am barefoot almost always, except when in school. I have rarely regretted a moment barefoot (though I have had the occasional spectacular bleed). And yet I wear shoes when I teach.

I like making bread, making beer, growing plants, singing, dancing. I have been sneaking parts of all of those into class. That I have to sneak them into the curriculum instead of trumpeting their presence in my classroom speaks to my cowardice and to my role as a government agent. It also speaks to a very weird social situation where I may talk more to a particular child than her parents.

I teach biology. It's messy. Always has been. It's wet, and chaotic, and real, and scary, and, ultimately, about death.

And life.

***

And what do I do?

I wear shoes in class.
I avoid death so I do not disturb my lambs.

But each and every one of us grows plants.
And every day, every day, I remind my students that the plants make stuff from their breath.
And in a few months, we will eat the fruit from the plants.

I do not, of course, call it communion, and would not for a whole lot of reasons.

But I will say this much. Though I have long given up on the Transubstantiation of the Host (but not the miracle of CO₂ and water to food), and though I will teach what I am hired to teach, I am closer to death than birth, and I will not lie to my students.

Ever.

You want a biology teacher? Someone who will put the logos (λέγω) of life in the classroom?

I'll do it.

A good biology course will change your child. If your child has not changed in my classroom, I've wasted her time.

The photos were taken today in North Cape May.
The cosmos were as alive as I'll ever be, and the crab as dead.

On ignorance

Anonymous — Sat, 07 Aug 2010 21:56:00 GMT

The sun slips toward the water. The breeze brings with it the thump-thump-thump of a karaoke box from Harpoon Henry's, a shore joint just over the dune. We barely here it over the waves, but we hear it.

I wandered into the muddy bay, up to my waist. The water is a little chilly, but my toes, buried in the sand, are warm, leftover heat from the sun hitting the beach before the tide rose.

A jelly comb drifts by, its edges marked by iridescent waves. A small crab scurries over my foot.

I am alive, as alive as I can be, and so is the jelly comb.

***

Tonight we're eating basil and cucumbers from the garden; yesterday we ate the tomatoes, and before that, the beans.

The tide rises, the tide falls, an incomprehensible volume of water moving twice a day a stone's throw from here.
Why? The moon, the sun, gravity....

Why? Well, the moon and the sun pull...

Why? Good Lord, child, no one knows why, no one....

***

The standardized tests allegedly test what we know. I want a test that tests what we don't know.

If our culture collapses in the next generation or two (and there are signs it may do just that), it will not collapse because of what we think we know.

It will collapse because of our stubborn refusal to acknowledge what we cannot know, or what we pretend to know.

If you watch a comb jelly even for a few moments on a late afternoon in August, really watch, allowing yourself to be washed by the beauty of a creature as foreign as Jupiter, you will (if only for a moment) grasp that we know nothing at all about anything beyond our human conceits.

And if you see the same creature glow at night, you might even worship it.

***

What would a test like that look like? How do you test for true ignorance?

Ignorance is easy to feign--some kids are motivated enough to study arcane ideas for hours in order to do well on tests that will get them ahead in life.

A child can be coerced into memorizing the equation for photosynthesis. Few kids grasp the significance, and why should they in a world dominated by lust and image and inopportune zits? It cannot be taught in a day, a week, a unit.

I could spend weeks on the sun alone, a magnificent star, a sphere of plasma. I could create plasma in the classroom, get my lambs excited about energy and matter as the boundaries between the two dissolve. Nothing here happens before the sun's existence.

But we do not worship the sun anymore.

We worship our words, our buildings, our cleverness.

So how would you assess ignorance, the awareness of how little we really know?
And should teachers spend more time showing what we don't know, instead of what we do?

The photo of Ra is from Falgun Angadia.
The sun photo gets credited to NASA--one massive solar flare hurled towards Earth, and it's lights out.