2. Sun- nuclear fusion Process:  H + H  He + Energy  All elements are made like this… we are all star dust! Qualities and Applications:  All colours and types of light emitted  This light energy fuels life on earth

3. Incandescence - light emitted from a very hot object Process:  Electrons passed through a wire (electricity) generates heat. Qualities and Applications:  Very Bright  Very inefficient only 5% of energy converted to light 95% to heat

4. Electric Discharge- light emitted from a heated gas, instead of a heated wire. Process:  Electrons flowing through a gas, heat it up, and light is emitted  Common form is the sodium vapour bulb where electricity is passed through a tube with a drop of sodium and mercury.

5. Fluorescence- substances that convert UV light into visible light Process:  Form of electric discharge, light emitted from mercury in a tube. Mercury produces ultra violet light which hits phosphor coating on glass which emits visible light. Qualities and Applications:  80% efficient 20% lost as heat  Last 10x longer than incandescent bulbs  Fluorescence dyes in money, semen, blood

6. Luminescence- light produced without heating an object Process:  The energy used to excite the atoms can come from a variety of sources. For example, Fluorescence is a type of luminescence because the energy used to excite the phosphor in a fluorescent bulb comes from ultraviolet light.  Phosphorescence, chemiluminescence, and bioluminescence are types of luminescence.

7. Phosphorescence - light emitted from phosphorescent materials Process:  Materials store energy and release it slowly over time Qualities and Applications:  Glow in the dark objects  Dim lights

8. Chemiluminescence- light produced from the energy released in a chemical reaction Qualities and Applications:  Glow sticks  Dim/long lasting lights

9. Bioluminescence- light produced by chemiluminescence inside a living organism Qualities and Applications:  Fire flies  Some fish  Jelly fish  Bacteria  Algae  Most produced by bacteria inside other living things