Hello Ran,
     I have some questions about today's lecture (Monday).  The water waves move
at the same speed no matter how much force is behind them, depending on
the depth.  Force (energy) and density (mass) are the two components
that dictate the speed of the wave.  So, where does depth fit in?

1.THAT'S A VERY GOOD QUESTION. IN THE CASE OF WATER THE RESTORING FORCE IS IN GENERAL DUE TO GRAVITY, BUT WATER WAVES IN VERY VERY SHALOW WATER ALSO INTERACT WITH THE BOTTOM. ITS AN EXPERIMENTAL FACT THAT THE RESTORING FORCE IS SMALLER AND THE SPEED OF THE WAVE IS SMALLER.

Is it connected to density?

2.YEP. THE SPEED OF THE WAVE IS

When you say density, do you mean the actual density of water itself, or the density regarding the quantity of water?

Density itself

     When you demonstrated with the rope, I caught the first aspect -
tension relating to energy.  But you flew right over the second
aspect...
3.AS IN THE CASE OF WATER: THE HIGHER THE MASS DENSITY OF THE ROPE THE SLOWER THE WAVE.

was it "waving" at the rate it was because it was travelling
through a low density medium, air?  Or because of its weight density?

     Back to the water waves...I know that waves are only on the surface
but the size and movement will vary according to the energy applied,
i.e. a gale force wind.  So, if the wind is powerful, the swells are
greater...

4.YEP, BUT THE SPEED OF THE WAVES IS THE SAME!

is that because a deeper level of the water is being moved or
because the surface is being moved more dramatically?

5.AS IN CLASS, THE AMPLITUDE OF THE WAVE IS LARGER, NOT THEIR SPEED.
Is this where
depth and density connect? SEE 1 ABOVE.
 

Answer II

My question from class was more simple.  It relates to the "junk
piles" that are created when two large waves crash on the beach; when
light waves collide, does it create something similar?  What happens?

WHEN TWO WAVES ARE COMBINED (CONSTRUCTIVELY, I.E. THEIR HEIGHT IS COMBINED) ON THE BEACH THE COMBINED WAVE HITS THE BEACH AND THEN THE COMBINED TROUGH BEHIND IT. SOMETHING SIMILAR HAPPENS WITH LIGHT WAVES. THE ELECTRIC AND MAGNETIC WAVES IN LIGHT (AN ELECTRO-MAGNETIC WAVE) PULL ON THE ELECTRONS IN THE SCREEN/FILM AND THEN PUSH THEM. AS A RESULT, IF ITS A FILM, THE PHOTOSENSITIVE MATERIAL IS "WIGGLED" AND IS READY TO BE DEVELOPED. IF ITS A SCREEN, THE LIGHT IS REFLECTED FROM THE "JUNK PILE" LOCATIONS.