First, I shared with you my intrigue over how a lake looked like a mirror in the morning and a sheet in the afternoon. To follow up on my intrique, I shared with you another pair of photos, in which another lake looked like a mirror and a lake from different vantage points (but at the same time of day). Some while later, I shared with you a rather contrived observation–a whiteboard can act like a mirror or a sheet in the same way a lake does, depending on your vantage point and how light shines on it.
This lent some support to the idea that angles are really important. One reason they are important is because shallow rays don’t penetrate deeply, so it’s like you are seeing the surface. When the sun is low and you are low, you have a high intensity beam glancing off the surface, showing you the mirror effect off the relatively lat surface. When the sun is high, you still get some low glancing reflections, but the mirror image is overwhelmed by the scattering of rays that penetrate deeper into the lake. When you are high, glancing rays never have a change to get to you, so all you see is the sheet effect.
Today, I’m struck by how similar looking at lakes is to what physicists do when they investigate matter. Physicists shine light at all kinds of matter and look what comes out. They vary the intensity. They vary the frequencies. They vary the angles. What comes out tells physicists about the structure of the matter that light was interacting with. In that sense, looking at lakes, especially from different angles from different perspectives with different intensities, is the naturalist’s scattering experiments.