Why is the sky blue?
A wave is a propagating disturbance that can transfer energy and information without requiring a net transport of matter over the same distance.
The short answer
A wave is a propagating disturbance that can transfer energy and information without requiring a net transport of matter over the same distance.
What is really happening?
A wave is a propagating disturbance that can transfer energy and information without requiring a net transport of matter over the same distance.
Frequency, wavelength and propagation speed are linked; what oscillates locally depends on the kind of wave and its medium.
Spectroscopy studies how matter emits, absorbs or scatters electromagnetic radiation as a function of wavelength, frequency or energy.
A useful mental picture
Visible light interacts with molecules in the atmosphere. Shorter visible wavelengths are scattered more strongly, which is why the daytime sky usually looks blue.