Posted On: Friday - March 13th 2020 7:39PM MST
In Topics:   Science  Educational Stupidity
I'll give the elementary school some credit today. This time, the science for the 8 y/o's was not more of the political scientific agenda, endlessly drilling into the kids heads that the Earth will be getting hotter, no doubt. No doubt, I mean summer's coming. They push this to the point of pushing parents a lot closer to homeschooling. As much as the kids hear about this Global Climate DisruptionTM, I can see how a few may turn into Grettas.
I should be happy to see the little lab reports showing the results of friction tests and the learning about the center of mass. If you're gonna teach it, you really ought to teach it accurately, though. I'll take one at a time.
The writing assignment, whatever I could read out of my kid's handwriting (he may become a Doctor!), was on the center of gravity. OK, you don't have to use the correct term, center-of-mass, as the colloquial is probably CoG. Then, I see that he wrote that the center of gravity is in the middle of a body. (They didn't write "body", but I want to be precise, dammit.) "In the middle" just kind of sucks. "Center" would have a better connotation, but the lesson is ignoring non-homogeneous bodies. That's my problem with it. You start with the general case.
Now, the teacher lady probably can't spend time to explain how one portion may be made of this, and the other of that. However, it's just wrong then. As a starter, just looking at geometry, I explained to my kid - "Look at that shovel - it's wider on the end. Where do you think it would balance?" We went over that, and I think he got it, without my talking about varying material density yet. I used a pillow for that. "Imagine this side was filled with rocks, and the other with the foam." "Oh yeah, then it would balance over here", he said. He got it immediately, yea!
Next, he showed me his friction papers. "Wait, but you rolled cars on sandpaper and then on construction paper [down a slope]? That's not friction you're measuring. That's rolling resistance." It's hard for most adults to understand rolling resistance. It's a weird bird, honestly. Friction is involved in rolling motion, but it doesn't determine what the kids were supposedly determining. Still, why should he start off understanding this wrong?
Though I'd have had to take out an engineering book even I'd probably have to look at for 10 minutes to explain the half of it, that wasn't my goal. "Here's what would have been a way to test the friction and make your experiment right. She should have had blocks of wood that you would slide over sandpaper and then construction paper." I don't think the boy really got that, but he understood there was a problem with testing friction with free-rolling wheels.
I also knew that this wasn't the teacher's lesson plan anyway. (No way do some of these ladies understand the half of this stuff.) It comes from a canned lesson. We both agreed that it wasn't that the teacher was doing it wrong, but whoever made up these, likely expensive "units". These assholes who make up this stuff may be the Ed School PhD's, and I'm sure even after getting help from physics guys, they'd still find a way to screw it up.
For the former error, I'm not really sure what you could change "in the middle" to, to be more accurate but still keep it understandable by these kids. How about show a few examples of non-homogeneous bodies (you definitely don't use either of those words), and some shapes like T's* to show where the "middle of the stuff" would be? Too much? Perhaps ...
On the latter error, just use sliding blocks, dammit!
Again, it's good they're doing this stuff versus all kind of other nonsense in their "science" time. I also wouldn't expect a teacher that even had an inkling of what I'm writing about here to push back on those that make these units. It's be a losing battle in all kinds of ways for her. But, I'm not about to give another, OK, one thin dime to any Ed School or to the PTO for more "science units" either, after seeing this sloppiness.
* Don't EVEN use an "L", as that bit about the center-of-mass being nowhere on the body is a bit freaky to anyone at first.