Monday, March 12, 2012

How Do You Measure Up?

I have a math-teacher confession. (Again.) It's not something I'm proud of. Not something I like to admit.

I'm not very good at estimating measurements.

Oh, I'm okay at the small stuff, particularly with length. I can say, "This is about two inches," or even, "That's about fifteen centimeters." But if you go much beyond something I can hold in my hands, I'm pretty hopeless.

This drove me nuts in driver's ed. Rules like, "When parking on the street, you must be X feet from the corner," were useless for me. Thirty feet, fifty feet, doesn't matter. I have no mental gauge for a distance like that.

Weights are even worse. Give me something and ask me if it's closer to five pounds or ten, and I'll be straight-up guessing. I know the fifty-pound bags of salt are pretty close to the limit of what I can comfortably lug around, so if something else is close to that, my guesstimate will be okay.

You know what this all has in common? Experience.

I can estimate lengths of things smaller than a breadbox because I've done a lot of measuring with a 12-inch ruler. I can tell when things are close to that fifty-pound mark because lugging those salt bags down to the basement is a memorable experience. I don't have a lot of experience measuring and knowing larger distances.

I bet if I played football, I'd have a pretty good feel for five yards vs. ten yards vs. twenty.

Except ... I have students who play football and don't know what a yard is.


As much as I'm not great with measurement, it's a much weaker area for many of my students. (Oh, if I could tell you how many times I've asked, "How many inches are in a foot?" or even, "How many months in a year?" and gotten blank stares!) Some of it's a language issue, and some is that it hasn't been prioritized in their previous years of math education. Mostly, it's a combination of both.

So, students in some of my math classes will be attacking objects with rulers and yardsticks and tape measures and scales. I will throw lots of questions at them like, "If you were measuring the water to fill up a bathtub, would you use gallons or cups?" And I will hope some of it sinks in.

What mad measurement skills do you have? What areas trip you up? Any tips or tricks? I'd love to hear 'em.


Jenny Kaczorowski said...

I am terrible at distances! The whole yards thing in driving especially! I do have a great sense of direction (ok that's not a measurement but it's something). I'm good with measuring food too. I can eyeball a cup or a tablespoon pretty acurately from cooking. That's about it...

Cat Woods said...

Like Jenny, I virtually always know which direction I'm headed and can tell you with a glance if the chopped onions are 1/4 or 1/2 cup. I'm also pretty darn good at feet (from designing all landscaping and remodeling projects) and height.

But, if you ask me about gallons and pounds, I'll likely be way off. Additionally, I am worthless when it comes to conversions.

Fun post!