Many thanks to you all for putting me straight on the 'black box'exercise -
in particular Guy Farish, Steven Wolf and Jon Monroe.
I had missed the fact that you can give students a list of possible objects
(or give them a duplicate set) so that they can use their powers of
deduction to identify which is in the box. This makes the exercise much
more credible to me, I was really having difficulty with the students
effectively having an infinite choice of possble items.
Another feature which makes the exercise work is giving the students access
to a reasonably full range of laboratory equipment (balances, waterbaths
etc). I had assumed that this exercise was done in a 'tutorial' type of
environment where this equipment would not be available.
I had also overestimated the size of the boxes - Steven's suggestion of
using a 35mm film canister is a good (and cheap) one.
I particularly liked the idea of putting a sweet (candy for you US people)
into one of the boxes so that there is a difference in behaviour at
different temperatures (and also that the treatment is not reversible)! In
fact I've been trying to think of a reverse example - possibly a small
amount of water sealed into a thin plastic bag - which would show
reversible behaviour at ambient and low (-20) temperatures.
This final comment from Guy:
>The idea is that they learn you can infer what an object
>is by indirect means and comparing it to something you already know
>about. [...] When they say "My box contains a
>marble", you ask them how they know. Ask what other possible items it
>might be, and what evidence they have that supports their hypothesis.
>This is a great tool for teaching the scientific method, and for clearing
>up points like how we know that electrons/protons/ions etc. actually
>exist. Try it out, I think you'll enjoy it and so will the students.
I will - you lot now have me convinced - many thanks again for your helpful
guidance!
Cris
___________________________________________________________________________
: Dr. Cris Woolston :
: Department of Applied Biology :
: University of Hull, Cottingham Road, Hull HU6 7RX, UK :
: RFC-822: C.J.Woolston at applied-biology.hull.ac.uk :
: Tel: +44 1482-465549 Fax: +44 1482-465458 :
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