The distribution of colours produced when white light is dispersed by a prism,
changing in wavelength from red (longest wavelength) to violet (shortest wavelength).
Seven colours are usually made out:
red, orange, yellow, green, blue, indigo and violet.
- fastest thing in the Universe is light – travels at 186,282 miles per second!
- light rays always travel in straight lines.
- the light pass from one material to another, light rays change direction – its called refraction.
Wavelengths of Light
- colours are different wavelengths of light.
- longest light waves that can be seen are red, and the shortest are violet.
- light is a form of electromagnetic radiation – light ray is a stream of tiny energy particles called photons.
- faint light from very distant stars – often recorded by astronomy-camera sensors called CCDs Â (Charge-coupled-devices – wikipedia); these count photons from the star as they arrive to build up a picture of the star at a long period.
Astronomy CCD Camera
- electromagnetic spectrum includes radio waves, ultraviolet light and X-Rays; visible light is the only part of the spectrum that can be seen by the human eye.
- all light is given out by atoms – light can be viewed as small packets of energy (photons) -when hits an atom, energy is produced as lightÂ all light is given out by atoms.