Armadillo's Book Blog

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1. My 12 yr. old aka dd built a hovercraft as part of her science fair project. Having watched the Junkyard Wars episode on hovercraft, I was quite worried about whether it would ever get off the ground and had actively discouraged dd from choosing this as her project. However, on her own, dd located really excellent plans for building the hovercraft. (The skirt folds in on itself and so forms a closed pouch, and then dd punched holes in the center of the bottom pouch. Which is much more efficient than an open skirt — all the air immediately pushes down.) Then, with just a short lesson about machine tools from her dad (and he did oversee the work) dd pretty much built the whole craft in a day, then took another day to punch the holes and attach the leaf blower (most of that time was spent worrying about where to put the holes). Herself. For example, dd came up with a very clever scheme for where to cut the air holes using a protractor and a pencil on a string for deciding where to cut them… ANYWAY, no limbs, not even any blood lost on the construction. Dd had allocated a week of debugging, but pretty much none was required.

THEN, in terms of the experimental design — dd was trying to determine whether additional weight slowed or sped up the hovercraft — I could tell that she had really no way of even starting to think about what her hypothesis should be. SO, I steered her (really, just emailed her a link) to a webpage with Newton’s 3 laws of motion. And, it was astounding how quickly she understood what F=MA means. And also, when you can sit motionless 1/2 inch above the ground, the law of inertia starts to make a WHOLE lot more sense.

Then, she weighed each of her classmates and had them ride the course she’d laid out to get the data. We had MANY volunteers.

And then, there came the time when dd had to write her report and create her board. I think that figuring out what the difference between \”weight\” and \”mass\” are and what the word \”gravity\” means took the most time. Finally, I pulled out our older daughter’s old AP Study Guide to Physics B & C, and the light bulb turned on over all our heads. No one really knows what the word \”mass\” is — it a property of matter having to do with how gravity affects it. And so, what is \”gravity\” — it is a theoretical force that explains how matter interacts. So we got to learn what recursion means, and at some point dd stopped and said, \”How come this took me so long to understand? I must be very stupid.\” (Must’ve been all of 20 minutes.) And I pointed to the cover of the AP Study Guide to Physics B & C and asked her if she knew what an AP was, and pointed out to her that this was a book for sophisticated high school students, and that, really, it was obvious from the definitions that even physicists don’t truly understand these terms.

Then, there were some very \”smart people\” (dd’s words) who served as the judges. They were very impressed with dd’s board and with her deep understanding of Newton’s laws. The hovercraft gives you SO many ways to understand inertia. It does not move (horizontally) unless force is exerted on it. It then goes and gives no indication that it intends to stop, once pushed. And then — action/reaction. So there is the leaf blower blowing air down. And — SOMETHING is blowing that air right back up. And that air is pushing the hovercraft up off the ground. (Enough air to lift a 300 pound adult. AMAZING. EERIE.)

Anyway, go now. Build a hovercraft. It is fun. Exciting. To build and ride.

2. Every year dd’s school goes on an Intensive Studies trip. This year’s was to the Southwest. We’d never seen the Grand Canyon before. We live on the coast, where it’s mostly cool and damp most of the time. We had some friends of the school show us Hopi. (The entire trip website is not completed yet. But here are some of the pages.)

One of my photos was named Sony’s Picture of the Day. We saw so many magical places.

So, it was a good school year. I don’t have any idea if dd learned any math or English. Next year is her last year at this school. I am already traumatized at the thought of investigating high schools. Perhaps we’ll just home school.