These photographs are taken at the Cow Green reservoir, high in the Pennines in Upper Teesdale. This first picture is taken in normal light conditions.
I noticed that the view was different when I had my polarising clip-on sunglasses on. If you notice in this second photograph, you can clearly see the waves on the water.
Here's how I took the photograph.
Light is an electromagnetic wave. It is transverse, which means that the oscillation is perpendicular to the direction of travel of the light. The oscillation can be up and down, it can be side to side or any angle in between. The polarising sunglasses only allow one direction of oscillation to pass. For example, they could allow the side to side through but stop the up and down. You can tell that less light is allowed through because the second picture is dimmer. The sunglasses must be blocking the light from the main part of the water but not from the wave crests, because I think the white tops on the waves are bright reflections rather than white water. Perhaps the wave crests are polarising the waves differently to the main part of the water. I'll have to think about that.
