Why is the sky blue?
The Earth's atmosphere scatters incoming light from the sun. This incoming light is made up of lots of different colours. Each colour of light has a different wavelength and because of this, different colours of light scatter at different angles when they hit the atmosphere. The shorter the wavelength of light, the more the light scatters. This means that the sky is filled with the light of shortest wavelengths, violet and blue. However, the cones in our eyes responsible for perceiving colours are more sensitive to the blue part of the spectrum, and so the sky appears purely blue.
HS
Related Physics GCSE answers
All answers ▸How long have you been studying physics?
State Newton's 2nd Law, and use this explain the vertical motion of a parachutist in the descent from her plane to Earth.
An electric heater has a power of 1000W. It is connected to mains electricity (230V). The heater is equipped with an Earth wire. a) Calculate the current in the heater. b) Explain the role of the earth wire as a safety feature.
Assuming no friction, describe the motion of a simple pendulum released from rest at t=0 at amplitude A? Provide information about its speed and position at characteristic times during one period. [The 1D equation of motion is described by a cosine]