[Phys-L] Re: The bulb-with-one-wire task: too tricky?

["Frohne, Vickie" <VFrohne@BEN.EDU>]

I've tried the exercise in a variety of situations, including calculu=
s-based physics.  Even physics and pre-engineering majors sometimes h=
ave trouble with this one.   In my experience, MOST people take a whi=
le to figure out the bulb, battery, and wire exercise.  But they cons=
istently  DO know something about light bulbs.  Most people immediate=
ly see the button on the end of the screw base as important. Usually,=
 they  immediately try putting the wire(s) on the bottom button, and =
when that doesn't work, they go for the glass envelope because it's t=
he biggest part of the bulb. Besides, the screw threads (which are th=
e only other visible part of the bulb) have the obvious function of f=
astening the bulb in the socket. Therefore the screw base has a funct=
ion already, and is therefore eliminated from consideration - compone=
nts are allowed to have only one function.  The second (electrical) f=
uncton of the base is discovered mainly by accident, if it is discove=
red at all.  When given two wires, people will invariably short out t=
he battery by attaching both to the bottom button of the bulb. Nearly=
 everyone realizes that two connections are necessary and that each e=
nd of the battery needs a wire. Several will ask if the polarity of t=
he battery matters.  This is a reasonable question, because most peop=
le also refer to an LED as a "butb."  The most frustrated will claim =
that the given task is impossible either because two wires are needed=
, or because every light bulb needs a socket.  People ARE using prior=
 common knowledge- this sequence of reasoning is very consistent. =
=20

IMHO, the battery-bulb thing is just a symptom of the bigger issue, w=
hich is that most people have no concept of the existence of  interna=
l mechanisms, much less the need to understand internal mechanisms. I=
f you ask someone to explain "how it works," they'll probably say "pu=
sh this button and turn that knob."    In everyday life, people use t=
echnology, but they can't fix it - most technology is unfixable.  The=
y either throw it out or get a plumber.  In everyday life, most peopl=
e never make anything that has to do something, either.  Most people =
even don't do arts and crafts.  "Home cooking" consists of popping so=
mething frozen into the microwave.  Decades ago, Arthur C. Clarke wro=
te that "Any technology, sufficiently advanced, will be indistinguish=
able from magic."  We're there.

VIckie Frohne



3. -----Original Message-----
=46rom: Forum for Physics Educators on behalf of Robert Cohen
Sent: Tue 2/22/2005 9:33 AM
To: PHYS-L@LISTS.NAU.EDU
Subject: Re: The bulb-with-one-wire task: too tricky?
=20
On Monday, February 21, 2005 11:47 PM, Richard Hake wrote:
> However, I think MIT graduates - the future elite of U.S.
> engineering/technology - should be able to figure out how to
> make the connections from their knowledge or observations that...

Is this from the Private Universe tapes?  If so, I thought the
interviewees were Harvard graduates.  Does anyone know exactly who wa=
s
being interviewed?  Were they all graduates?  Does anyone know their
majors?  I'm assuming they weren't science but I don't know.

____________________________________________________
Robert Cohen; 570-422-3428; www.esu.edu/~bbq
East Stroudsburg University; E. Stroudsburg, PA 18301