1. Electromagnetic Radiation Conceptual Physics    J. Beauchemin 2009

2. Waves… a review  Most waves are either longitudinal or transverse.  Sound waves are longitudinal.  But all electromagnetic waves are transverse…

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4.  When an electric field changes, so does the magnetic field. The changing magnetic field causes the electric field to change. When one field vibrates—so does the other.  RESULT-An electromagnetic wave. Click here  Animation: Interaction of vibrating chargesInteraction of vibrating charges

5. Electromagnetic waves  Produced by the movement of electrically charged particles  Can travel in a “vacuum” (they do NOT need a medium  Travel at the speed of light  Also known as EM waves

6. EM Spectrum Defined  Electromagnetic Spectrum—name for the range of electromagnetic waves when placed in order of increasing frequency, decreasing wavelength.

7. B. Waves of the Electromagnetic Spectrum  Click here  (Animation—Size of EMwaves)—Size

9. Radio waves  Longest wavelength EM waves  Uses: TV broadcasting AM and FM broadcast radio Heart rate monitors Cell phone communication

10. Radio Transmission  A transmitter produces an electrical current. This energy is transmitted to an antenna.  The antenna produces electromagnetic waves (radio waves) that get sent through space.  The receiving antenna picks up and converts the radio waves into sound that we can hear

11. AM vs FM

12. Microwaves  Wavelengths from 1 mm- 1 m  Uses: Microwave ovens Bluetooth headsets Broadband Wireless Internet Radar GPS

13. Microwaves  Microwaves are sent through and “excite” the atoms that make up food, which results in heat energy.

14. Infrared Radiation  Wavelengths in between microwaves and visible light  Uses: Night vision goggles Remote controls Heat-seeking missiles

15. IR  Anything that emits heat will emit IR. So all of us are emitting Infrared radiation right now!  IR can be used to “see” heat

16. Visible light  Only type of EM wave able to be detected by the human eye  Violet is the highest frequency light  Red light is the lowest frequency light

18. Ultraviolet  Shorter wavelengths than visible light  Uses: Black lights Sterilizing medical equipment Water disinfection Security images on money

19. UV Health Risks  Skin cancer  Cataracts  Suppression of the immune system  Premature aging of the skin

20. When are UV rays the strongest?  UV rays tend to be stronger in the summer and at noon, when the sun is highest in the sky. The UV Index forecasts the strength of the sun’s harmful rays. The higher the number, the greater the chance of sun damage.

21. Ultraviolet (cont.) UVAUVB and UVC EnergyHighest of UV waves Lower than UVA Health risks  Extremely low risk for DNA damage  Can destroy Vitamin A in skin  Can cause DNA damage, leading to skin cancer  Responsible for sunburn

22. X-rays  Tiny wavelength, high energy waves  Uses: Medical imaging Airport security Inspecting industrial welds

23.  X-rays work because x-rays pass through soft tissue, but not hard tissues like bone. The x-rays that pass through the soft tissue are detected and the image is then generated.

24. Gamma Rays  Smallest wavelengths, highest energy EM waves  Uses Food irradiation Cancer treatment Treating wood flooring

25.  All stars produce gamma rays, but massive stars produce the most!  Gamma ray bursts are produces when a star explodes or goes supernova  Gamma rays from the sun do not reach earth because our atmosphere filters them out!

27. Using the EM waves to view the Sun AnimationAnimation—View a Galaxy at different wavelengths

28. Image credits 1. http://www.antonine- education.co.uk/New_items/MUS/images/Making6.gif http://www.antonine- education.co.uk/New_items/MUS/images/Making6.gif 2. http://www.geocities.com/researchtriangle/campus/6791/einste in12.jpg http://www.geocities.com/researchtriangle/campus/6791/einste in12.jpg 3. http://abyss.uoregon.edu/~js/glossary/wave_particle.html http://abyss.uoregon.edu/~js/glossary/wave_particle.html 4. http://www.astro.princeton.edu/~gk/A402/electromagnetic_spe ctrum.jpg http://www.astro.princeton.edu/~gk/A402/electromagnetic_spe ctrum.jpg 5. http://science.hq.nasa.gov/kids/imagers/ems/radio.html http://science.hq.nasa.gov/kids/imagers/ems/radio.html 6. http://www.nentjes.info/Palace/radio-6.gif http://www.nentjes.info/Palace/radio-6.gif 7. http://www.mobilewhack.com/motorola-h12-bluetooth- headset.jpg http://www.mobilewhack.com/motorola-h12-bluetooth- headset.jpg 8. http://www.stuffintheair.com/radar-real-time-weather.html http://www.stuffintheair.com/radar-real-time-weather.html 9. http://www.imaging1.com/gallery/images/AV%20Night%20visi on%20goggles.jpg http://www.imaging1.com/gallery/images/AV%20Night%20visi on%20goggles.jpg 10. http://www.global-b2b- network.com/direct/dbimage/50329753/Study_Remote_Control.jpg http://www.global-b2b- network.com/direct/dbimage/50329753/Study_Remote_Control.jpg 11. http://www.georgiaprismaward.com/The_Prism_Story_files/PRI SM%20brand%20imagemed.jpg http://www.georgiaprismaward.com/The_Prism_Story_files/PRI SM%20brand%20imagemed.jpg 12. http://science.hq.nasa.gov/kids/imagers/ems/uv.html http://science.hq.nasa.gov/kids/imagers/ems/uv.html

29. Image Credits 13. http://farm3.static.flickr.com/2385/2381723771_12548f 4bd1.jpg?v=1217429879 http://farm3.static.flickr.com/2385/2381723771_12548f 4bd1.jpg?v=1217429879 14. http://intamod.com.au/images/uv2.JPG http://intamod.com.au/images/uv2.JPG 15. http://science.hq.nasa.gov/kids/imagers/ems/xrays.html http://science.hq.nasa.gov/kids/imagers/ems/xrays.html 16. http://www.sciencelearn.org.nz/var/sciencelearn/storage /images/contexts/see_through_body/sci_media/neck_x_r ay/17945-5-eng-NZ/neck_x_ray_full_size_portrait.jpg http://www.sciencelearn.org.nz/var/sciencelearn/storage /images/contexts/see_through_body/sci_media/neck_x_r ay/17945-5-eng-NZ/neck_x_ray_full_size_portrait.jpg 17. http://www.epinion.eu/wordpress/wp- content/uploads/2008/05/airport-security1.jpg http://www.epinion.eu/wordpress/wp- content/uploads/2008/05/airport-security1.jpg 18. http://science.hq.nasa.gov/kids/imagers/ems/gamma.ht ml http://science.hq.nasa.gov/kids/imagers/ems/gamma.ht ml 19. http://www.aboutnuclear.org/print.cgi?fC=Food http://www.aboutnuclear.org/print.cgi?fC=Food 20. http://www.roswellpark.org/files/1_2_1/brain_spinal/ga mma%20knife%204c.jpg http://www.roswellpark.org/files/1_2_1/brain_spinal/ga mma%20knife%204c.jpg