1. Light

2.  EM Waves have many uses  EM Waves have different frequencies

3.  Range of all EM frequencies

5.  Measured in Hertz – one cycle per second

6.  Radio Waves (Low Frequencies)  Microwaves  Visible Light  Infrared Light  Ultraviolet Light  X-Rays  Gamma Rays (high frequencies)

7.  Modulation - variation of amplitude or frequency when waves are broadcast ◦ AM – amplitude modulation  Carries audio for T.V. Broadcasts  Longer wavelength so can bend around hills ◦ FM – frequency modulation  Carries video for T.V. Broadcasts © 2000 Microsoft Clip Gallery

8. ◦ Radio Waves  Def. – Longest wavelength and lowest freq.  Uses – Radio, TV

9. Microwaves ***These were accidentally discovered for use to cook food when microwaves melted a candy bar in a researcher’s pocket! Higher energy than radio waves radar (detecting aircraft and ships) cell phones (radio transmitter and receiver)

10. ◦ Infrared Rays  Def – Light rays with longer wavelength than red light.  Uses: Cooking, Medicine, T.V. remote controls

11. Frequencies lower than visible light. They can not be seen but can be felt as heat.. We will see this in “The Core”

12. In other words, we experience this type of infrared radiation every day in the form of heat! The heat that we feel from sunlight, a fire, a radiator or a warm sidewalk is infrared. Infrared light is even used to heat food sometimes - special lamps that emit thermal infrared waves are often used in fast food restaurants!

18. ◦ Ultraviolet rays.  Def. – EM waves with frequencies slightly higher than visible light  Uses: food processing & hospitals to kill germs’ cells  Helps your body use vitamin D.

19. ◦ X-Rays  Def. - EM waves that are shorter than UV rays.  Uses: Medicine – Bones absorb x-rays; soft tissue does not.  Lead absorbs X-rays.

20. ◦ Gamma rays  Def. Highest frequency EM waves; Shortest wavelength. They come from outer space.  Uses: cancer treatment.

21.  Clear Your Desks except for one piece of paper.  10 Questions  30 seconds per question

22.  A. Hertz  B. meters  C. liters  D. Decibels

23.  A. By Anton van Luewenhook B. By looking at subatomic particles  C. By accident  D. None of the above

24.  A. Periodic Table  B. Electromagnetic Realm  C. Instagram  D. Electromagnetic Spectrum

25.  A. After Morning  B. Amplitude Magnification  C. Amplitude Modulation  D. Angry and Mean

26.  A. Frequency Modulation  B. Fast Moving  C. Frequency Movement  D. Frequency Motion

27.  A. Blue  B. Yellow  C. Red  D. Pink

28.  A. Infrared Rays  B. Microwaves  C. Light Rays  D. Gamma Rays

29.  A. Clean stalls  B. Help patients walk around  C. Kills germ (cancer) cells  D. None of the above

30.  A. Silver  B. Gold  C. Lead  D. Platinum

31.   A. Modulation