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Exactly! This reminded me of the Little Planet what if http://what-if.xkcd.com/68/ http://what-if.xkcd.com/68/ Munroe claims on a small, super massive planet, y

by jere 13y ago

Exactly! This reminded me of the Little Planet what if http://what-if.xkcd.com/68/ http://what-if.xkcd.com/68/ Munroe claims on a small, super massive planet, you could overcome escape velocity with a sprint. It doesn't work the same on the moon obviously, but only because the moon has significant gravity. >Which, pointed out a discussant, suggests that students are using buoyancy as an analogy — if you’re heavy enough you sink, if you’re light enough you float. Why is this such a stupid assumption? That's how it works on Earth. I don't believe that these kids are failing to think; they're using reasonable analogies, but lacking specific knowledge about the environment on the moon. >"All science is either physics or stamp collecting." - Ernest Rutherford Basically the authors are complaining that the students haven't collected a specific stamp.

leoc 13y ago
Well, the lack of an atmosphere on the Moon should rule out buoyancy. Myself I don't doubt that many of the wrong answers really were the result of faulty intuitions or dodgy reasoning.
- jere 13y ago
  Of course, but that's another environmental variable.
informatimago 13y ago
No, on the contrary! It's a packers vs. mappers question. The packers collect stamps, and when asked whether the pen falls on the Moon, get out the stamp that says that pens don't fall in space. The mappers will apply the physics model, the formula, and come out with the right answer (or approximation) corresponding to the right situation. That's a big problem with packers: you teach them stuff, but they retain only half of it, forgetting the applicability conditions. "Nothing can go faster than light!" Only material stuff, and only in the vacuum. But there are mediums where light will go slower than a walking human. "There's no perpetual motion machine!" Right, only when you consider a CLOSED system. There's no physical entity smaller than the Universe that's a closed system. Even black holes have inputs AND outputs! And so on.

by jere 13y ago

leoc 13y ago

Well, the lack of an atmosphere on the Moon should rule out buoyancy. Myself I don't doubt that many of the wrong answers really were the result of faulty intuitions or dodgy reasoning.

jere 13y ago
Of course, but that's another environmental variable.

informatimago 13y ago

No, on the contrary! It's a packers vs. mappers question. The packers collect stamps, and when asked whether the pen falls on the Moon, get out the stamp that says that pens don't fall in space. The mappers will apply the physics model, the formula, and come out with the right answer (or approximation) corresponding to the right situation. That's a big problem with packers: you teach them stuff, but they retain only half of it, forgetting the applicability conditions. "Nothing can go faster than light!" Only material stuff, and only in the vacuum. But there are mediums where light will go slower than a walking human. "There's no perpetual motion machine!" Right, only when you consider a CLOSED system. There's no physical entity smaller than the Universe that's a closed system. Even black holes have inputs AND outputs! And so on.