Ok, this is *way* off topic, but I'm hoping the people here are a bit
smarter than my stupid coworkers (I guess stupid _self_ is implied.)
:-)
The following web site explains the basic behavior of a concave mirror
and pretty much agrees with everything I remember from physics:
http://www.physicsclassroom.com/Class/refln/U13L3a.html
If the object distance is beyond the focal point, the reflected image
will be inverted. If the object is at the focal point, the reflected
image will hit a singularity. If the object distance is less than the
focal length, the object will be magnified and right-side up.
Now, I have a concave mirror with a 40" radius of curvature. This
means it has a 20" focal length. My problem is that I'm not observing
behavior that matches the theory.
My initial speculation is that the position of my eye is an important
factor that isn't addressed by the simple theory, but from the simple
theory, I don't see how that could be possible.
Here are some things I'm observing: if my eye is closer to the mirror
than the focal distance, I see myself and the entire room right side
up. Even though objects in the distance (i.e. the other side of the
room) are further than the focal point, they are still right-side up.
If I move my eye point away from the mirror and watch myself, I seem
to hit the singularity at 40" which is the center of curvature, not
the focal point. Yes, I've verified that the radius is indeed 40" and
is most definitely not 80".
If my eye point is further than 40" I can move an object (such as a
pen in and out and it hit's the singularity at 40" and inverts beyond
that.)
If I move my eye away from the mirror and watch an object on the
otherside of the room, it hits the singularity and inverts at 20".
This sort of agrees with the above theory except it's a distant object
that never moves, only my viewpoint is moving. ?!?
I've been trying to reconcile this all in my head and have put myself
into a state of complete befuddlement ...
Can anyone tell me what stupid thing I am missing?
Curt.
--
Curtis Olson IVLab / HumanFIRST Program FlightGear Project
Twin Cities [EMAIL PROTECTED] [EMAIL PROTECTED]
Minnesota http://www.menet.umn.edu/~curt http://www.flightgear.org
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