This is a type of wave that travels in one direction, but the energy travels perpendicular to this direction

Transverse wave

Explanation:

Transverse wave can be simply defined as a wave in which the wave particles oscillates perpendicularly to the direction of propagation of the wave. Some of its examples includes light wave and radio wave.

Transverse waves can be either mechanical or electromagnetic wave, where the mechanical waves requires a medium for its wave propagation, and electromagnetic wave does not require any medium for its propagation.

Thus, transverse waves can travel through with or without the presence of any medium.

blue light is scattered in different directions by the tiny molecules of air. blue is scattered more than other colours because it has a shorter distance to travel which results in smaller waves. this is why we see a blue sky most of the time.