Register to reply

Question about optics: glasses

by Loki1342
Tags: glasses, optics
Share this thread:
May19-11, 02:45 AM
P: 2
Hi everyone,

I was riding home today and got water all over my glasses. It annoyed my until I got home - I looked up at a light, and I could focus really clearly on something that was splattered on my glasses. It looked like it might've been dirt, or mud, because it almost seemed to zoom in enough to see individual particles (or constituents?) of whatever it was. My explanation off the top of my head is this:

Due to the differing refractive index of glass and water, when a thin film of water is spread over the surface of a lens, you're creating a crude telescope. When light is incident from far enough away (so that incoming light rays are parallel), it zooms in on whatever is splattered on the surface. When you move too close to the source, the incoming light is no longer uniform (the rays aren't parallel) so it scatters off whatever is splattered on the surface. I guess it just so happened that the focal length was just rigth for what was splattered on my glasses.

Seems kinda cool to me, and it was definitely zooming in on something. Am I on the right track? If not, can anyone explain it?

Thanks! :)
Phys.Org News Partner Physics news on
Step lightly: All-optical transistor triggered by single photon promises advances in quantum applications
The unifying framework of symmetry reveals properties of a broad range of physical systems
What time is it in the universe?

Register to reply

Related Discussions
I have two same glasses... General Physics 3
Trouble reading small print General Discussion 21
SAVE ME! HW DUE AT MIDNITE! Optics/Glasses problems Introductory Physics Homework 1
Sun Glasses General Physics 15
I'm Getting Glasses General Discussion 84