Re: Challenge Question #2 rebuttal

From: Jerry Bailey <>
Subject: Re: Challenge Question #2 rebuttal
Date: Tue, 12 Nov 1996 07:00:10 -0800 (PST)

Here here!

Jerry Bailey
Tillicum Middle School
Bellevue, Washington 

On Sun, 10 Nov 1996, Verl L. Smith wrote:

> Hi Chris & all,
> I presented the answer to Challenge #2 to my physics class because the
> concept of not being able to see the other side of the canyon bothered me:
> "...if you stood on one rim of the Valles Marineris, you wouldn't be able to 
> see the other rim because it would be out of sight over the horizon !"
> I asked my class:
> "How can the other rim of a chasm be "over the horizon" -- what is rising out
> of that chasm to block the view?  Or - how shallow is this canyon that its
> floor becomes the horizon?  Maybe I need a picture (or profile to scale) to 
> help visualize this."
> Philip grabbed the challenge and came up with a very good response.  Basically
> for the far wall of the canyon to be over the horizon (the horizon being the
> floor of the canyon itself) the canyon must be 200km or more in width and be
> 1.5km or less in depth.  According to the data we dug up on Marineris, the
> maximum width is about 200km, but the depth is up to 7 or 8km.
> Philip first did use calculus to solve the problem, but the solution he
> presented here relies only on geometry & a little trig.  I would hope that
> the readers of this list would be able to follow his presentation with 
> careful reading and maybe digging some long unused math concepts out of some
> corner of our brains.
> Philip is truely a gifted student and a joy to work with - even though he
> often operates at a level beyond me.  We explore and learn together; I cannot
> say I teach him, he often teaches me.
> As for the level of the questions - Chris asked:
> >More fuel for the fire, says I.  We need challenge questions we can
> >attempt to SOLVE.  How can my 5th graders and I be expected to generate
> >these kinds of responses???  Surely we are not expected to generate that
> >level of response!  
> I am new to this list, but from what I have observed by looking at the 
> student responses posted all levels are accepted.  The challenge questions
> are answerable at different levels.  Obviously 5th graders wouldn't be 
> expected to answer the way Philip did, but they should be able to think
> through the questions and provide their own answer - even if it misses the
> mark.  The emphasis should be on getting the students to think at their level
> and reason through to an answer.
> I say on to Challenge 3 - have you tackled that with your class?  Get three
> volunteers up in front of your class and have them do a Martian moon dance
> and play with rotating & revolving to grasp the concept.  It should be fun.
> Verl Smith
> Ava High School
> Ava, MO