Wednesday, December 7, 2011

Biology: Measuring tiny things

This week we learned a technique for measuring the length of tiny things. The kids measured a louse (for the uninitiated that's singular for lice), onion cells, and a human hair. This activity gave new meaning to the question: Do you have thick hair or thin hair?

So what unit do you use when you're measuring something so small? Meters, centimeters, millimeters? At this scale we're talkin' microns, 1000 of which make a millimeter. Using a ruler, the kids measured the field of view. Then they converted this number to microns. After examining a specimen, they estimated how many times it would fit within the field of view, did some simple math, and came up with a measurement that was within 2.5% of the accepted value. Not bad for a day's work!

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