Presentation on theme: " Electromagnetic Radiation Radiant energy that exhibits wavelength- like behavior and travels through space at the speed of light in a vacuum. Example:"— Presentation transcript:
Electromagnetic Radiation Radiant energy that exhibits wavelength- like behavior and travels through space at the speed of light in a vacuum. Example: The sun light, energy used in microwave oven, the x-rays used by doctors.
Visible and/or Ultraviolet (UV) energy is absorbed and excites the electrons to higher energy levels. The electrons then emit (give off) energy in the form of visible light with a time delay. visible or UV light intime delay visible light out
Glow in the dark stuff Zinc sulfide—older glow- in-the-dark material— doesn’t last as long Strontium aluminate— newer glow-in-the-dark material—lasts much longer http://cdn2.ioffer.com/img/item/128/809/943/gJBaVSbiNnEwYRe.jpg
Chemicals are mixed and the energy excites electrons. Instead of energy being released in the form of heat, the energy is released in the form of “cool” light. This is chemiluminesence. If this occurs in a living organism it is called bioluminescence. chemical energy invisible light out
Light sticks Fireflies Many deep sea organisms http://www.mbari.org/itd/images/retrospective/colobonema.jpg http://static.howstuffworks.com/gif/light-stick-2.jpg
Mechanical energy excites the electrons in adhesive molecules, which then excite the electrons around nitrogen atoms in the air. The energy is then emitted in the form of visible light. (Magic tape example) In the case of wintergreen, the methyl salicylate molecules are fluorescent, and so the mechanical energy excites the electrons in the wintergreen flavoring. mechanical energy in visible light out