I found that water flowing from a tap is casting a shadow, somewhat like this: If you see through the water flowing from the tap, you can see that the pink colour of the wash basin is visible almost clearly. What is the cause of the flowing water casting a shadow? Is it because the turbulence prevents any light from getting refracted through the stream, thereby casting a shadow? N.B.: Maybe this question has been asked before. If so, moderators may delete the thread.