light

7 articles · All tags

• How Lasers Work: Stimulated Emission and Coherent Light
  A laser amplifies light through stimulated emission to make a narrow, coherent beam of one colour. Learn population inversion, the parts of a laser, and its uses.
• Why Is the Sky Blue? Rayleigh Scattering Explained
  The sky is blue because air molecules scatter short-wavelength blue light far more than red light — Rayleigh scattering — and the same effect paints sunsets red.
• Auroras: The Science of the Northern and Southern Lights
  How auroras glow: solar particles racing down Earth's magnetic field lines excite oxygen and nitrogen high above the poles — the colour reveals which gas and altitude.
• Electromagnetic Spectrum
  The continuous range of electromagnetic radiation from radio waves to gamma rays, classified by frequency and wavelength.
• Doppler Effect
  The change in the observed frequency of a wave when the source and the observer move relative to each other.
• Wave–Particle Duality
  The quantum-mechanical fact that entities such as light and electrons exhibit both wave-like and particle-like behavior depending on the experiment.
• Special Relativity
  Einstein's 1905 theory of space and time, built on the constancy of the speed of light and the equivalence of all inertial frames.