Friday Fact: Chalk

~= comes out of fog =~

What? Huh?

Wait...what day is it?

OMAN! It's been a week!

Sorry, friends. I did not mean to be so absent, here. I've just been rather absent...everywhere.

Head cold.

You know.

But I had to force myself back to the world of the living to explore this burning question:

Chalk. What the heck IS that stuff??

Y'know, used-ta-be that schools specialized in chalkboards. Teachers would display arithmatic puzzles on the wall-sized board of black in beautiful contrast with their little piece of white chalk, engaged in an un-ending pirouette from board to class to board to class to...

Students would practice their hand at addition, subtraction, congugation, participle dangle-ation, etc. on their own desk-sized version of a blackboard, and their own wonderful piece of the horrid little chalk.

Professors would walk around wtih hand-shaped chalk marks on the seats of their pants.

Now, of course, the black board has been abandoned in favor of the less messy white board. The screetchy chalk has been replaced in the education market by the squeeky dry-erase marker.

And - sadly - dentention no longer consists of slamming chalk board erasers together to "clean" them and make a great white cloud of a mess on everything else.

Not that I know anything about detention.

But chalk is still cool. Kids everywhere still know exactly what it is.

Just maybe not exactly what it's made of.

Which is where I come in.

Turns out that CHALK is a form of limestone that is composed of the mineral calcite. Calcite is basically calcium carbonate.

I just had to laugh when I learned this - because, apparently I'm obsessed with all forms of calcium carbonate. (I wonder what else I'm intrigued by that can be explained by this freaky substance?)

For blackboard and sidewalk chalk ('cause there's lots of other kinds, did you know?), the idea is that the stuff is compressed into long sticks, that when rubbed over a rough surface crumbles and leaves traces of itself loosly attached to the surface.

It destroys itself so it can leave it's mark.

There's something poetic about that, I think.

Some crazy (and incredibly patient) artists use chalk to create incredible feats on sidewalks. Where people walk. Where rain washes it away. There's something poetic about the imperminence of it, too, I think.

There is not, however, ANYTHING poetic about the unholy sound it can make when used at a wrong angle. And nobody knows what that angle is. It's a sneaky angle that is suddenly wrong - and then everyone is sorry.

Chalk's one revenge.


Grandpa Rusty said...

If one runs out of chalk, one can use lima beans. Their textures are the same. And they taste the same.

MikkSolo said...

Can't remember exactly, but there is some science behind the squeaky chalk. It has to do with the length, not the angle. Long chalk pieces (the nice new ones) are more likely to squeak. That's why we don't ever hear squeaks at church because they are all the little stubby pieces!