## Wednesday, May 20, 2009

### Help ! I'm confused. My math mojo is deserting me ...

Okay, here's the question. NEA sends out this blurb about germs in school and you just know there's stupid people involved. I'm reading the thing and seeing that the water fountain has 2 700 000 bacteria per inch.

Huh? Shouldn't that be "per square inch"?

Okay, maybe a misprint. I read on. "But the very worst, most disgusting, just say no for germ's sake, was the public sandbox, where NSF's analysts found a horrifying 7,440 bacteria per inch!"

Huh? Huh?

How is this the very worst? The water fountain is something like 4000x as much. The cafeteria plate that they eat off is twice the number! What the hell? With mathematical analysis like this, it's no wonder that elementary teachers don't find it necessary to do math or find it embarrassing when they screw up teaching fractions.

"I just don't DO math. Tee-hee-hee. Giggle."

Can't you just hear it now? "Let's make a silly crack about how video games are bad for you - 551 sounds like a BIIIIIG number!" Too bad it's one-third the number of bacteria on a typical student's hand.

"I don't DO fractions, either. Giggle. Snark."

# Eeek! There's a germ on my desk!

### The bacteria and germs are out there, just not where you might think.

Even as fears of a flu pandemic fade, it's worth noting where all kinds of germs lurk in your classroom. In 2006, the non-profit NSF International took its microscope to two Michigan elementary schools to measure the general bacteria population on different surfaces.

 Water Fountain Spigot 2,700,000 Cafeteria Tray 33,800 Cold Water Faucet 32,000 Hot Water Faucet 18,000 Cafeteria Plate 15,800 Computer Keyboard 3,300 Toilet Seat 3,200 Student's Hand 1,500 Animal Cage 1,200

* Units are number of aerobic bacteria per inch

This year, NSF's microbiologists widened their scope and swabbed surfaces in 26 public places. Thanks to your school custodians, schools starred in the comparison. School bus seats practically sparkled with fewer than 10 bacteria per square inch, as did books and basketballs. Still quite clean were desks, gym mats, and computer mice.

But leaving schools behind, they found a little germ factory on the video game controls in movie theaters-551 bacteria per square inch. (Proof that those games aren't so great for mind AND body.) But the very worst, most disgusting, just say no for germ's sake, was the public sandbox, where NSF's analysts found a horrifying 7,440 bacteria per inch!

Fortunately, your classroom doesn't resemble a sandbox. And it's not too hard to keep it from breeding like one. Check out these tips from veteran custodians on fighting germs in the classroom.

Those who can, do. Those who can't, teach teachers or run their union.

1. Sheesh, You hit it on the head. We are so sloppy about math, most kids think "what's the use?!"
It's not your math mojo that's deserting you, obviously. Maybe the goofballs who wrote the report live in "Flatland."
- Brian (a.k.a. Professor Homunculus at MathMojo.com )

2. You've got it all wrong! In order to count the germs, they have to line them up first! ;) That's why it takes so much time and money to conduct these studies, you know.

3. We understand that there may be some confusion about the units used to report the findings of this study. Please visit, http://www.scrubclub.org/info/topten.aspx to see the actual study. NSF International's Microbiologists conducted this study in 2005 and posted the results in Total Aerobic Bacteria per Square Inch (Colony Forming Units (CFU/in2)).

4. I'm making fun of the scientifically clueless writer, editor, artist, and webmaster, you moron. At least one of these should have noticed the units error. It got repeated quite a few times but was used properly in the text, but was used incorrectly in the drawing and the caption.

"We understand there may be some confusion." Horse manure. You're confused, not me.

The thing that I laughed at most was the interesting lack of understanding of numbers.
Cafeteria Tray 33,800
vs "a horrifying 7,440 bacteria per inch!" in the sand box.

Probably an elementary school teacher masquerading as NSF.

5. Curmudgeon: I concur with your conclusion. In 1998, when my daughter was in 5th grade, I sat through a presentation by an elementary school teacher who was describing the new approach to teaching 5th- and 6th-grade math. Emphasis was to be on "higher order thinking skills", rather than rote memorization of facts. I recall the teacher saying that it was unnecessary to remember "facts", such as that "the formula for area is pi times the diameter - or something like that". And it struck me that anybody who actually understood the geometry would not have made that mistake. So, when I have worked with my kids I have taken pains to make sure that they knew the difference between linear measure, area, and volume ... and that the little exponent after the unit really does have meaning!