Chronology Current Month Current Thread Current Date
[Year List] [Month List (current year)] [Date Index] [Thread Index] [Thread Prev] [Thread Next] [Date Prev] [Date Next]

Re: A question about mirrors



A simple geometric construction, which allows construction of a pair
of objects of opposite handedness and which only requires knowing what
"perpendicular" means, might be:

Select a pair of perpendicular directions (call them A and B). Now,
there are only two choices for a third perpendicular direction (call
them C and D). The triplet of directions, ABC, has opposite
handedness to ABD; and reflection in a mirror can transform ABC into
ABD and vice versa.

This occurred to me I started thinking about this problem (since the two
co-ordinate systems are referred to as left and right handed). But I believe
that here we are using a specific geometrical object and its mirror image.
We could just as well use the L-shaped solid fromed by nailing two 1x1x2
blocks at right angles one on top of the other. With a little manipulation,
I could easily convince myself there were only 2 forms which could not be
super-imposed. But this doesn't me closer to a definition for a similae
demonstration for *any* object.

Note that this construction doesn't tell you which triplet is
right-handed and which is left-handed; only that they have opposite
handedness. For us and other intelligent beings to "correctly" assign
the handedness, we all would have to have access to an object on which
we all agree has a given handedness.

We can, I think, conduct an experiment involving radioactive decay.





__________________________________________________

Do You Yahoo!?

Talk to your friends online with Yahoo! Messenger.

http://im.yahoo.com