- Dutch astronomer, Christian Huygens, (1629–1695) stated that light was vibrations or waves which spread everywhere through a space-substance called ether.
- By 1864 James Clark Maxwell stated that light waves were electromagnetic waves.
- The quantum theory states that light may behave as both particles and waves.
- Light from an object must reach the eye to be seen.
- Most objects are visible because they reflect light from a luminescent or glowing source.
- Life is dependent upon light. Without the trapping and storing by chlorophyll in living plants of light energy, there would no chain of life.
- The Sun is the main source of "natural" light.
- A light year is the total distance that light will travel in one year.
- Materials which are heated to above 1400 °F (800 °C) produce light.
- Solids and liquids are then incandescent (glowing with heat).
- Some objects are luminescent without it being necessary for them to be at high temperatures.
- Certain chemicals when mixed together give off light called chemiluminescence.
- A firefly's tail produces a "cool" light.
- A gas through which an electric current passes will emit light that is not incandescent.
- The brightness and color of light will not vary from gaseous materials, but depend upon the nature of the gas.
Some facts about Light
