Wednesday, February 27, 2008

What should sixth graders know about science?

Some years ago, E. D. Hirsh Jr. compiled a list of what he thinks kids should know by the time they enter junior high, everything from proverbs to geography. The chapters on science list 442 terms, from acid to x-ray. It's a good list, but, as Hirsch would be the first to acknowledge, a vocabulary is itself no basis for literacy. What is required is an understanding of how the world works and our place in it.

If it were up to me, I would organize the primary school science curriculum around five key concepts:

1) The scale of the universe. Every classroom in America has a solar system model, probably hanging from the ceiling like a mobile. Hirsch's dictionary has a solar system diagram. The trouble is, the models and diagrams give no sense of true scale. In fact, they are hugely deceptive. So get the kids out in the playground. Use a basketball for the sun. The Earth is a grain of sand 80 feet away, and the moon is a pinpoint 2 1/2 inches from the Earth. Add the other planets to scale. Have the kids walk around in this model solar system and feel the vastness of space.

Alpha centauri, the next-closest star, is another basketball in Hawaii.

How many stars in the Milky Way galaxy? Make a spiral galaxy on the classroom floor with a box of salt. Astronomers estimate that there are a hundreds of billions of stars in the galaxy. Have the kids figure out how many thousands of boxes of salt it would take to have a grain for every star. It will blow their minds.

2) The dynamic Earth. Soft-boil an egg and break it open. Now you've got something approximating the inside of the Earth. We live on eggshell. The ground is literally moving under our feet. Every year Boston creeps another inch away from Paris. Los Angeles slips an inch toward San Francisco. Every few hundred million years the face of the Earth is made anew.

Why don't we notice all this moving around?

Without saying anything, set up a motorized telescope in the classroom and turn it on. It will rotate once a day on its axis. Sooner or later someone in the class will notice that the telescope has moved. That's when to talk about geologic time and human time.

3) DNA. Every school in America should have a stick-and-ball model of part of a strand of DNA. A big model, as tall as the classroom, a model that shows every atom. Sure, it would be the most expensive teaching tool in the school, but it would be worth it.

There's an arm's length of DNA in every cell of our bodies.

Live with the model in the classroom. Bask in its beauty. Do all the things teachers usually do: Grow bean sprouts in Styrofoam cups, keep turtles in a terrarium, watch a butterfly emerge from a chrysalis. But all the while keep an eye on that beautiful strand of DNA.

4) Evolution. Kids love dinosaurs, so talk about dinosaurs. But not just the monsters of Jurassic Park. Talk about all of the dinosaurs. Two hundred million years of dinosaurs. The big ones and the tiny ones. The rapier-toothed meat-eaters and the gentle nibblers of plants.

Roll out a paper time line in the longest corridor of the school. Start with Day One, the formation of the Earth. Walk across 3 1/2 billion years of life, most of the way down the corridor, before encountering anything but microbes. Give the dinosaurs their few feet of time. Find our sliver of space at the end of the line.

Construct a family tree of life on Earth. A big one, with a primal bacterium at the base of the trunk, dinosaurs on their truncated branch, and every kid in the class at the end of a twig.

And send any textbook that calls evolution a theory rather than a fact back to the publishers.

5) Reliable community knowledge. Talk about the difference between theory and fact. Stress that all knowledge is tentative and partial, but that some knowledge is more secure than others. The evolution of animals and plants across millions of years is a reliable fact; astrology is poppycock.

Paper one wall of the room with the front pages of supermarket tabloids: "Woman gives birth to dinosaur baby," that sort of thing. Paper the opposite wall with posters of galaxies, planets, coral reefs, rain forests, dinosaur fossils, the human nervous system, and that famous face of Einstein with the big, brooding, curious eyes. Let the kids decide which world they prefer to live in.

That's enough. I wouldn't care very much if a sixth grader didn't know the definitions of acid and alkali, or pistil and stamen. If the kid had a sense of place,a sense of time, a sense of wonder -- that would be scientific literacy enough for me.

The rest, the 442 definitions, will come in their own sweet time.