I wrote about the fresnel effect earlier, in the post Interaction of Light and Materials. Here is a simple experiment to see this effect on a not very glossy surface. Grab a sheet of printer paper or note paper, not the photo kind with a glossy coating, and look at it like this to see the effect:
1. First look at the paper with a light source behind you and the flat side of the paper facing you. The light will bounce off the paper mostly surface scattered before reaching your eyes and the paper looks like a really rough material, in the sense that the reflected light is almost fully diffused.
2. Then look at the reflection of light in the paper while facing the light source and tilting the paper so that it is almost parallel to the light direction. You will see the reflection of the light source much sharper and more intense. More of a specular reflection at this angle.