[FRIAM] Illusion

[Nicholas Thompson]

To produce the illusion:

Take an ordinary water glass, put a little water in it, stretch some
plastic wrap tightly over the glass and put  it in the microwave for a few
seconds.

Leave it in the microwave for a minute to cool down .(Please don't do
anything stupid and scald yourself.)

Remove the glass (see above, "....stupid") from the microwave. The  plastic
should have formed a concave beaded surface on the top of the= glass.

Wonder, "What is the mathematical form of that  surface?"

Examine the surface under a vertical  lamp (like a  desk lamp or a ceiling
bulb)

An image of  the  lamp willl appear floating inches above the surface of
the plastic.

Tilt the glass just right, and you will see a *convex* surface enclosing
the top of the glass.

Wonder:  "Have I made a parabolic surface?"

Write email to Friam.

Receive dope slaps from colleagues for not looking it up on the internet
first.





-- 
Nicholas S. Thompson
Emeritus Professor of Psychology and Ethology
Clark University
nthompson at clarku.edu
https://wordpress.clarku.edu/nthompson
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