Mississipi drainage basin is about half the area of the lower 48 =>
** 1X10^13 m^3 per year **
Method 2
Cross-sectional area of Mississippi at mouth
1km by 100m (I think this may be too big, but honesty forces me to give
my first estimates)
Speed at mouth = 10 km/hr (same comment)
Volume per hour = 10^9 m^3 per hour
Times hours in a year
= ** 10^13 m^3 per year **
________________________
Joel Rauber
Department of Physics - SDSU
Joel.Rauber@sdstate.edu
605-688-4293
| -----Original Message-----
| From: Forum for Physics Educators
| [mailto:PHYS-L@list1.ucc.nau.edu] On Behalf Of John Denker
| Sent: Friday, April 08, 2005 12:16 PM
| To: PHYS-L@LISTS.NAU.EDU
| Subject: Mississippi puzzle
|
|
| 1) How much water flows down the Mississippi (at, say, New Orleans)
| in a year, approximately? Don't look anything up. Just estimate
| whatever raw data you need.
|
| -- Arno Penzias, when he was in charge of all research at Bell
| Labs, liked to spring this question on members of the technical
| staff. Woe betide the person who blurted out "I have no idea".
| Arno would yell back "you must have SOME idea ... don't tell me
| you have no idea ... FIGURE IT OUT."
|
| -- Anybody with a US high-school education "should" be able to
| answer this _without_ looking anything up. It just requires
| strength of character, i.e. not giving up in the face of a
| problem that seems hard. It also requires marshalling lots
| of facts that may not, at first glance, have seemed relevant.
|
| 2) Find a second independent solution to the Mississippi problem.
|
| -- Somehow knowledge of the first solution is a psychological
| impediment to finding the second solution.
|
| -- OTOH if you can reach the same conclusion by two different
| avenues, it greatly increases the reliability of the result.
|
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