Thursday, November 6, 2014


Somehow I seem to have gotten on to a theme of gadgets. I was watching something on the local PBS station and as is customary when a show ends a bit before the hour mark, there was a short clip. This time it was one from a series called the History Quiz, where people are given strange objects from the past and try to figure out what they were used for. Here's what they were asked to look at in this episode.

So a densiometer measures the shade coverage by the leaves of trees above. It's not to be confused with a densitometer, which Google continually wants to steer me to and which has a variety of meanings, but which seems to mainly have to do with optical density, or how much light passes through or is absorbed by  an object. Yeah, let's not go too far down that road right now.

As the little clip shows, the densiometer, by measuring shade, can tell various things about an ecosystem, including its health. The one in the clip is pretty fancy. But guess what, kids? You can make your own with stuff you have at home. It won't look like this:

 But it still looks pretty fun.


  1. Oh, my gosh. The response to "What's a densitometer?" ought to be "Huh?"

  2. Yes, even if you were savvy about densitometers, you could still be dense about densiometers. And apparently Google is, because it just rewrote the word for me behind my back. But I corrected it.

  3. Greetings! I'm doing some work for teacher development at Hamline University's Center for Global Environmental Ed. I'm seeking your permission to use your photograph of a densiometer from this post. We aren't charging money for this curriculum. We are creating a virtual forest transect experience for middle school students and teachers. Please let me know. Thank you.