Reflections of water viewed from airplane

[mbernhar]

Sometimes when you look out the airplane window, you see bright flashes of light from the ground, caused by swimming pools, rivers, and puddles. The places where the flashes occur seem to move along with the airplane. What are the conditions (time of day, direction you are looking) that lead to this effect?

[SteveD]

I seem to remember from my schooldays (a long time ago now!) that, for reflected light, the angle of incidence = the angle of reflection.

Consequently, if the angle between your eyes looking out of the aircraft window and the surface of a swimming pool, river etc below equals the angle between the sun and the pool, river etc, then you will see a reflection of the sun. This reflection will appear to flash because the aircraft is moving.

[mbernhar]

Steve, thank you for the information. I was forgetting about the angles being the same.