he can now explain all this to his students. he is trying to improve rather than just teaching them what he knows. geez.

(in fact glass is liquid that “spills” slow in time)

I wish people would stop spreading this. Glass is NOT a liquid. It is an amorphous solid.

From List of common misconceptions

Glass is not a high-viscosity liquid at room temperature: it is an amorphous solid, although it does have some chemical properties normally associated with liquids. Panes of stained glass windows often have thicker glass at the bottom than at the top, and this has been cited as an example of the slow flow of glass over centuries. However, this unevenness is due to the window manufacturing processes used in earlier eras, which produced glass panes that were unevenly thick at the time of their installation. Normally the thick end of glass would be installed at the bottom of the frame, but it is also common to find old windows where the thicker end has been installed to the sides or the top

It’s almost as bad as the “We only use 10% of our brain” canard.

EDIT: added wiki link and quote

Glass and water are similar (in fact glass is liquid that “spills” slow in time) so when u make the pennie wet and stick it to the “mirror surface” you provide the same densitiy from both sides of the mirror (water) which ruins the mirror effect (needs two far different densities: air & water/glass) blabla

my two pennies anyways

    http://en.wikipedia.org/wiki/Total_internal_reflection

It is the same effect that makes some of the surface of a swimming pool look like a mirror when viewed from under water. If the water is completely still you can see up and out through a disk directly overhead. The rest of the surface looks like a mirror, reflecting the image of the walls of the pool.

Bill