Science of Christmas lights

[smc]

Originally Posted by franalexes

Here's a question for any physics majors out there.
I'm sitting here by my window with a string of Christmas lights and against the background of the darkness of night I notice that the lights reflect off the window panes. I can understanf how the light reflects off the inside of the glass, but how does it reflect off the far side?
If I look closely there are two reflections on one pane of glass. The near surface and the far surface.
Explain it to me.

Look up the Huygens-Fresnel Principle and you'll understand.