- question of the week - color of the week  


Light scatters when it travels anywhere else than in a vacuum, e.g. in atmosphere. This scattering is physically due to the collision of photons to the molecules in the material. In the atmosphere blue light scatters easier than red. The sky looks blue because we see the scattered light of the sun.

Sunset looks red because the light travels long way through the atmosphere and the blue light has scattered into the space.

The scattering is an important factor also in the paper industry. Paper is often described by a mathematical model, where scattering is an important factor. The models are used e.g. to estimate the color properties of paper.