1. Slide 1 © 2004 By Default! A Free sample background from www.awesomebackgrounds.com By: Brittany D. Alexander

2. Slide 2 © 2004 By Default! A Free sample background from www.awesomebackgrounds.com Electromagnetic Waves EM waves have a wide range of wavelengths. The entire range of wavelengths is called the Electromagnetic Spectrum.

3. Slide 3 © 2004 By Default! A Free sample background from www.awesomebackgrounds.com Electromagnetic Spectrum The relationship between the wavelength and energy of waves in various parts of the electromagnetic spectrum can be shown as follows:

4. Slide 4 © 2004 By Default! A Free sample background from www.awesomebackgrounds.com Visible Light Visible light is the range of electromagnetic waves that can be detected by the human eye. The entire range of visible light is called the visible light spectrum.

5. Slide 5 © 2004 By Default! A Free sample background from www.awesomebackgrounds.com Visible Light The wavelengths of visible light are in the middle range of wavelengths/frequencies of electromagnetic waves. The longer the wavelength, the lower the energy of the wave is.

6. Slide 6 © 2004 By Default! A Free sample background from www.awesomebackgrounds.com Visible Light The human eye reacts to different energies and frequencies of light so that different colors are seen.  Higher frequencies (shorter wavelengths) are perceived as colors toward the blue-violet range and have higher energy.  Lower frequencies (longer wavelengths) are perceived as colors toward the orange-red range and have lower energy.

7. Slide 7 © 2004 By Default! A Free sample background from www.awesomebackgrounds.com

8. Slide 8 © 2004 By Default! A Free sample background from www.awesomebackgrounds.com Absorption and reflection of light waves by various materials results in human perception of color as follows:

9. Slide 9 © 2004 By Default! A Free sample background from www.awesomebackgrounds.com Perception of Color Each wavelength is a different frequency. R.O.Y. G. B.I.V Red, Orange, Yellow, Green, Blue, Indigo, Violet

10. Slide 10 © 2004 By Default! A Free sample background from www.awesomebackgrounds.com Perception of Color Most materials absorb light of some frequencies… and reflect the rest.

11. Slide 11 © 2004 By Default! A Free sample background from www.awesomebackgrounds.com Color Filters Color filters allow only certain colors of light to pass/transmit through them; they absorb or reflect all other colors. For example, a blue filter only transmits blue light. Objects seen through a blue filter will look blue if the objects reflect blue. Objects of other colors will appear black because the other color wavelengths are being absorbed by the filter.

12. Slide 12 © 2004 By Default! A Free sample background from www.awesomebackgrounds.com Infrared Radiation Infrared radiation is the range of electromagnetic waves with frequencies lower than red on the visible spectrum, thereby having longer wavelengths and less energy than red wavelengths.

13. Slide 13 © 2004 By Default! A Free sample background from www.awesomebackgrounds.com Infrared Radiation All objects emit infrared radiation, and hotter objects emit more infrared radiation than cooler objects. Heat energy is transmitted by infrared radiation. When objects absorb infrared radiation, they become warmer. How did the plane suddenly become warmer on the underside?

14. Slide 14 © 2004 By Default! A Free sample background from www.awesomebackgrounds.com Ultraviolet Radiation Ultraviolet radiation is the range of electromagnetic waves with frequencies higher than violet on the visible spectrum, thereby having shorter wavelengths and more energy than violet wavelengths

15. Slide 15 © 2004 By Default! A Free sample background from www.awesomebackgrounds.com Ultraviolet Radiation Because of the high energy of the ultraviolet radiation, too much exposure is damaging to the eyes and skin.

16. Slide 16 © 2004 By Default! A Free sample background from www.awesomebackgrounds.com UV light Damage ULTRAVIOLET VIEW Some dermatologists are giving patients ultraviolet light assessments of sun damage to the skin. This picture was taken from the New York Times.