Sunday, September 14, 2008

Reform Science and the fate of the science experiment

"It's not as if I have the kids go in and do a science experiment, and then go in the next day and do another experiment, and so on.." my son's 6th grade science teacher told me.

Rather, he assured, today's science classes focus on more important things, like communicating scientific ideas through presentations and posters.

The science experiment is now an optional home venture: the fourth and final option on the weekly homework sheet, listed after (1) the calculator-facilitated metric conversion worksheet, (2) the calculator-facilitated area & volume worksheet, and (3) the communications assignment (pick a science article, summarize it, and write a personal reflection of what you thought about it).

And the experiment's instructions are so imprecise that it's not clear what you're actually supposed to be doing or testing out.

The question:

Does the amount of salt in water affect the amount of freshwater produced?

In one trivial sense, the answer is yes. Any significant amount of salt reduces the amount of freshwater down to zero, because when you add enough salt to freshwater it's no longer fresh.

In another trivial sense, the answer is no: adding substance B to substance A doesn't subtract from substance A.

Whatever. Maybe the directions will somehow illuminate matters:
Mix salt and water to make salt water.
Do the proportions matter? A sprinkling of salt? A whole ladel full?
Add about 2 inches of the water to a pot.
But remember the area and volume sheet! Inches are linear! What on earth is "2 inches of water"?
Put an empty glass in the bowl.
Just "put?" Centered? On its side? Upside down?
Seal plastic wrap over the top, weigh it down with a rock (centered above the bowl?)... Now you've made a solar still.
Oh, OK. Let's re-position the cup accordingly.

But what if no one at home knows what a solar still is already?
Repeat with fresh water.
"Two inches" of water?

In a pot the same size as the first? Actually, it's a good thing this is left unspecified: we don't have two equal pots. (Do most people?)

Do two inches of fresh water get you the same amount of H2O as two inches of salt water? Is this what we're trying to find out? Or is starting out with the same amount of H2O a prerequesite for answering a different question about what happens to the water later on?
Put the stills outside in the sun. Leave it [sic] alone for a few hours, or even a whole day. When you're ready, measure the water.
In inches?

And doesn't how long we leave them out affect the answer we get?

Assuming we even know what the question is...

Yes, I see now that communicating scientific ideas is very important. Perhaps we'll go with Option 3 next time.

1 comment:

Ganeida said...

um, we don't do science experiments but we *are* random learners, completely non~sequential, & I think the other side of the brain learners. We don't do mess. Art is not mess. ;D
However as a homeschooler I would fail those instructions for an English paper so I can only imagine how terrible they are from a scientific viewpoint.