1. 1. Electro- magnetic waves  are waves that can travel through matter or empty space where matter is not present.  longer the wavelength, the lower the energy of the wave. Fill in Notes p. 25

3. 2. Radio Wave Wave Microwaves Microwaves  Low frequency, long wavelength, lowest energy  used for communication, such as radios, tv  Higher frequency radio waves  Used in Radar and cell phones. (microwaves) ADD THIS

4.  3. Infra - InfraredRadiation  means before  frequencies lower than red on the visible spectrum, thereby having longer wavelengths and less energy than red wavelengths.  4. All objects emit infrared radiation, and hotter objects emit more infrared radiation than cooler objects.  Used to keep food warm, or cook food, like a toaster

5.  4. Heat energy is transmitted by infrared radiation.  The more Infrared radiation is absorbed = warmer

6. Visible light  5.Visible light is the range of electromagnetic waves that can be detected by the human eye.  The wavelengths of visible light are in the middle range of wavelengths/frequencies of electromagnetic waves. entire range of visible light is called the visible light spectrum

7. 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.

8. Ultraviolet Waves Ultraviolet Waves  6. Frequencies higher than violet damages skin and eyes due to high frequency.  UV waves helps the skin produce vitamin D  Seen by bees

9. 7. X-rays 7. X-rays  Higher frequencies and energies  Produced by the Sun and other stars.  Pass through soft tissue but absorbed by more dense material. Because of this we can tell we have a broken bone.

10. 8. Gamma  is the most harmful EM ray.  Produced by radioactive substances, the sun and other stars.  Kills normal cells,but can also be used to fight cancerous tumors.

11. Interaction of Light Waves TransmissionAbsorption  The passage of an EM wave through a medium.  The disappearance of an EM wave into the medium.

12. Interaction of Light Waves TransparentTranslucent  most of the light passes through. Ex. Air, water, clear glass. Uses: light bulbs, clock faces  transmit some light but they also cause it to spread out in all directions. You can see light through translucent materials but cannot see objects clearly. Ex. frosted windows, notebook paper.

13. Interaction of Light Waves Opaque  No light passes through  Reflect light, absorb light, or both. Ex. Wood, mirrors, metal, fabric

14. Why we see color ColorWhiteBlack  Is determined by the wavelength being absorbed or reflected.  An object is the color it reflects. Ex. A shirt that is red is reflecting the red wavelength but absorbing all others.  Reflects all colors in visible light.  Absorbs all colors in visible light.

15. Why we see color Colored Filters   allow only certain colors of light to pass/transmit through them; they absorb or reflect all other colors. Ex. 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. Let’s experiment with filters:   http://micro.magnet.fsu.edu/pri mer/java/primarycolors/colorfilte rs/index.html http://micro.magnet.fsu.edu/pri mer/java/primarycolors/colorfilte rs/index.html