October 19th, 2010
I got an email from a professor I know. I know a lot of professors, and I won’t say who or where, but this should be more broadly known:
This past week I helped grade midterm exams for Calculus I…One of the problems involved an astronaut on the lunar surface throwing a rock vertically into the air. The height of the rock, in meters, was explicitly given: s(t) = (*)t – 0.8t^2 where t is the time in seconds, and an explicit initial velocity (*) was given. The last part of the problem asked for the acceleration due to gravity on the moon. I was hoping that students could differentiate twice and answer -1.6 m/sec^2 (or more reasonably 1.6 m/sec^2). However about 12 students (at least one in each class, writing the exam in different rooms) answered that “the acceleration is 0 because the moon has no gravity”.
This is reminiscent of the “Heavy Boots” story I first saw on usenet 20 years ago. I don’t know if it’s true, but it is unfortunately plausible.
There are misconceptions out there that can make smart people sound stupid. The truly smart person ferrets these things out and fixes them in their own head. I have misconceptions, and because I write this blog sometimes they come out (e.g., thinking that Catholics actually believe what their church tells them about contraception, because I naively expect people to be self-consistent). I’d rather get it right than keep believing something that isn’t true, but it’s hard work.
It’s easy to simply lament that our education is bad, that people are stupid…it’s harder to do something about it.
I do. I don’t just whine about it on the internet. I teach introductory astronomy to non-science majors, created Launch Pad, edited Diamonds in the Sky, give public talks, etc. I’m giving an exam next week that covers surface gravity and the moon, among other things. I’ll ask a question about this “no gravity on the moon” and see how well I did. Unfortunately I don’t have a pre-test, but maybe I’ll do one next semester. When talking about Galileo, Newton, and laws of motion, I did show this video, which is way cool:
My students, at least the ones who came to class that day, ought to remember. Seeing a video can shake a misconception loose in a way that just talking about it cannot, likewise seeing a video portraying something incorrectly can build or lock-in a misconception like cement (e.g., what an “asteroid field” looks like, as in Empire Strikes Back). That’s one reason I care about getting science in books and movies right.
Some of this stuff is small and funny, like a secretary who sent out an email advising us where to find newly installed recycling “bends.” Some of this stuff, however, leads to public opposition to science, bad policy, and more. Misconceptions about sex can lead to unwanted pregnancy, STDs, and death. Misconceptions about… There’s a long list of things like this. Sometimes it’s funny, but sometimes it’s very serious, and it’s hard to know where to draw the line.
Next time you hear someone say something you think is wrong, correct them, politely and casually. Smart people can handle it. But try to be absolutely sure that the misconception is theirs, and not yours. That’s having integrity.
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It would be interesting to ask those 12 students why they think there is no gravity on the Moon. If confronted directly they might see they made a studid mistake and have a reason why. I wonder if they were just confused and wondered if the problem required calculating air resistence, and they meant to say there was no air resistence on the Moon.
Read the Heavy Boots link — it explains how the misconception is adjusted in light of Apollo astronauts (they wore “heavy boots!”).
Unfortunately, I think you’re giving the students way too much credit here. This was a calculus class, and it’s very likely air resistance was never ever mentioned.
This is somewhat an advanced question for most people in the US, let alone the world. I pretty much cringe when I see reporters asking people on the street their opinions about things. Now, I understand that such interviews are often mined for the most entertaining bits, but the majority of people don’t seem to know much about much, but they seem to think they do.
whats worse? Thinking there is no gravity on the moon? Or that there is no gravity on orbit?
but yes, people are not thought to THINK. Teachers must press students to think.
“why do you think there is no gravity on orbit?”
“because people float inside the spaceships, and the spaceships wont fall”
“so why does the spaceship remains around the planet, instead of just going away in a straight line”?