Re: [Phys-l] Unit Conversions (was Mass and Energy)

[Jack Uretsky <jlu@hep.anl.gov>]

Hi all-
	Michael Edmiston provides us with the following tale:
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> a student asks for help with the capacitor lab and has inverted the
> conversion from picofarads to farads.
>
> ME:  Is a picofarad larger or smaller than a farad.
> Student: Smaller
> ME: Okay, so if you are converting picofarads to to farads, do you
> expect to get a really big number or a really small number.
> Student: Big
> ME: Is a penny larger or smaller than a dollar.
> Student: Smaller.  Are you telling me I did the picofarad thing
> backwards?
> ME: If you count the pennies in your penny jar and get
> three-hundred-forty-two, is that a lot of dollars or not so many
> dollars?
> Student: I did the picofarad thing backwards didn't I.  So if I switch
> it around it will come out okay, right?
> ME: I'm not going to tell you.  You figure it out.
> Student: Well if I didn't do it backwards you wouldn't be so stressed
> out about it.
>
> Goodness.  Not only does he not understand how to think this through, he
> doesn't even want to think it through.  Apparently that's too painful.
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	I don't think that this tale leads to Mike's conclusion.  Not at 
all.  I suggest that there is no way to decide from this story what 
the student wants or what he/she wants to think about.
	Hint:  Where is the main focus of the student's attention, and 
what is your guess as to the reason for that focus.
	Hint:  "I tell students" is a different phrase from, "What 
students seem to learn in my class is ..."
					Regards,
						Jack



--
"Trust me.  I have a lot of experience at this."
		General Custer's unremembered message to his men,
		just before leading them into the Little Big Horn Valley