Tuesday, May 27, 2008
how tall is that?
Last week I was listening to KNX 1070 news radio while sitting in traffic. The weather was slightly cloudy with a bit of a breeze around me, but a listener from another county was telling the newscaster about how he'd just seen a tornado overhead. The fact that there was a tornado in Southern California was disconcerting, but it was how he described it that left my mind reeling. When the newscaster asked how big the tornado was, he answered with hardly a pause: "I'd say it was about 300 feet tall, and 3 city blocks wide." Forget the tornado, this was astounding to me. I got the '3 city blocks wide' reference; I've seen that, so I can relate. But how could he make such a quick estimate of 300 feet tall?
If you're a spacially-challenged person, like I am, your mind probably draws a blank anytime there is a reference to a really big (or, really small) measurement. 300 feet tall: how big is that?
Sensible units to the rescue. Fill in a measurement, and sensible units will spit out 3 comparisons to help us visualize how much.
How does this help our students? We recognize the importance of reading comprehension. Basically, where there is no inner visualization, or even questioning of meaning when one reads a word or term, there is no neuronal activity. No learning takes place. If we give our students convenient tools to enhance their understandings, we can help them keep those neurons firing, seeking connections.
I'm glad sensible units offers three analogies. I've seen those London buses, lots of them in a line, and I can imagine a big stack of African elephants. But a stretched out human small intestine?