Wednesday, February 3, 2010

Sherlock Holmes and peanuts

Last night Snuggler had to do her physics homework. Her science class at Co-op is using the Real Science 4 Kids curriculum, which I find very solid and yet kid-friendly. The assignment for yesterday was on gravitational potential energy, and the homework was to drop a book from various heights onto a peanut, to see when it cracked open.

We rigged up a ruler between two blocks, so we could measure how high above the peanut we were starting. Then Snuggler hauled out The Complete Sherlock Holmes. (No, she hasn't been reading it; Big Guy and Eldest just finished.) Dontcha know that 1,122-page tome can crack open a peanut from a height of two inches? Go, Sherlock!

Then we decided to see what would happen if we used a less ponderous volume. We tried Voyages in English 3 (which we're not using this year), which is a tad more than 200 pages. That took a drop of 12" to crack a peanut. We don't have a scientific scale here, but weighed Sherlock on our regular bathroom scale, and it came out at 6.2 pounds.Voyages was too light to register on the scale. I tried to get Snuggler to figure out how much Voyages ought to weigh, based on what we knew about Sherlock and the weight and height needed to crack a peanut with it. Either that was too abstract or I worded the question poorly, because she had no idea what I was talking about. Then I made a table headed like this:

Book name          Height  * Weight =  gravitational potential energy

We filled in the info we had for each book, and lo and behold it suddenly looked like a math problem, where the only missing information was how much Voyages weighed.

 Needless to say, Little Guy was into smashing peanuts with books, too. Given the mess that was created, it was a good thing the prior lesson was on WORK.

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