How does energy keep the world going? How is energy conserved?

Explanation:

The conservation of energy law states that energy cant be created or destroyed, only transferred. Since energy cant be created or destroyed, the amount of energy in the universe is completely constant.

Energy keeps the world "going" because we use it every single day in our life. Everything in the universe uses some sort of energy. We digest food for energy, we use electrical energy for electronics, we convert electrical energy into heat energy for heaters and such, we use solar panels to power our houses. There are countless examples of how energy keeps the world "going."

scattering of light by tiny particles in air to produce the colors we see on sky, is dependent on the following factors:

(i) wavelength of light

(ii) size of the scattering particle  

(iii) distance traveled by light through the atmosphere.

according to rayleigh's law of scattering, the amount of scattering is inversely proportional to the fourth power of its wavelength. shorter the wavelength, greater is its scattering. hence violet/blue light is scattered more than red.

sun's light is a composite light ( visible light) with wavelengths in the range 400 nm (violet) to 700 nm (red). as sunlight passes through our atmosphere, the molecules of air scatter light according to their wavelengths. during sunrise and sunset, the sun's position is below the horizon. hence light from the sun travels a greater distance in the atmosphere when compared to its position a noon.

as sunlight enters the earth's atmosphere, blue light is scattered away and at the end of its journey in the sky, only red and orange wavelengths remain in the beam.

hence at sunrise and sunset, the sky appears reddish orange.