EM spectrum and wave.pptx

Electromagnetic Waves

1. Guess What is this?

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10. What is common to all of the given example?

11. Electromagnetic Spectrum Module 1

12. Learning Competencies/Objectives: Describe how electromagnetic (EM) Wave is produced and propagated. Compare the relative wavelengths, frequencies and energies of the different regions of he electromagnetic spectrum. Cite examples of practical applications of the different regions of EM waves.

13. What is Electromagnetic Spectrum? Electromagnetic Wave?

14. Can light travel through a Vacuum (i.e., empty space)? Can sound travel to a vacuum?

15. Electromagnetic waves are created by the vibration of an electric charge. This vibration creates a wave which has both an electric and a magnetic component.

16. An electromagnetic wave is a type of wave that can travel through empty space example light...

17. Unlike sound waves, which need "something" to travel through (for example, water or air), electromagnetic waves are able to travel through "emptiness" or a vacuum.

18. An electromagnetic wave transports its energy through a vacuum at a speed of 3.00 x 10 8  m/s (a speed value commonly represented by the symbol  c ). The propagation of an electromagnetic wave through a material medium occurs at a net speed which is less than 3.00 x 10 8  m/s. 

19. Hans Christian Oersted 1777-1851 OMG! The compass needle move near the current-carrying wire. This shows electric current creates magnetic field. Activity 1: How it came about… http://www.rare-earth-magnets.com/hans-christian-oersted/ http://en.wikipedia.org/wiki/Heinrich_Hertz http://simple.wikipedia.org/wiki/Michael_Faraday http://soulconnection.net/glossary_in_depth/maxwell.html Image credit:

20. Hey Hans, the opposite could be true! A changing magnetic field produces an electric field. Activity 1: How it came about… http://www.rare-earth-magnets.com/hans-christian-oersted/ http://en.wikipedia.org/wiki/Heinrich_Hertz http://simple.wikipedia.org/wiki/Michael_Faraday Michael Faraday 1791-1867 http://soulconnection.net/glossary_in_depth/maxwell.html Image credit:

21. Activity 1: How it came about… http://www.rare-earth-magnets.com/hans-christian-oersted/ Heinrich Hertz 1857-1894 http://en.wikipedia.org/wiki/Heinrich_Hertz http://simple.wikipedia.org/wiki/Michael_Faraday http://soulconnection.net/glossary_in_depth/maxwell.html You got it right Maxwell. I proved the existence of EM waves! Image credit:

22. James Clerk Maxwell 1831-1879 Activity 1: How it came about… http://www.rare-earth-magnets.com/hans-christian-oersted/ You both got it right! An electromagnetic wave exists when the changing magnetic field causes a changing electric field, which then causes another changing magnetic field, and so on. http://en.wikipedia.org/wiki/Heinrich_Hertz http://simple.wikipedia.org/wiki/Michael_Faraday http://soulconnection.net/glossary_in_depth/maxwell.html Image credit:

23. EM spectrum is a continuum of EM waves arranged according to frequency and wavelength.

24. It shows a gradual progression from the waves of lowest frequency to the waves of highest frequency or vice versa. The different EM waves do not have exact dividing region.

25. Image Credit: http://imagine.gsfc.nasa.gov/science/toolbox/emspectrum1.html Newton set up a prism near his window, and projected a beautiful spectrum 22 feet onto the far wall. Further, to prove that the prism was not coloring the light, he refracted the light back together. Image credit: http://www.webexhibits.org/colorart/bh.html The modern understanding of light and color begins with Isaac Newton.

26. Image Credit: http://imagine.gsfc.nasa.gov/science/toolbox/emspectrum1.html Image credit: http://coolcosmos.ipac.caltech.edu/cosmic_classroom/ir_tutorial/discovery.html Frederick William Herschel (1738 - 1822) In 1800 he performed a famous experiment where he tried to measure the temperature of different colours of the spectrum by placing a thermometer on each colour. He found to his amazement that the hottest part of the spectrum was in a place where there was no colour at all . It was a spot beyond the red end of the spectrum. For the first time it was possible to talk about invisible light . This hot light became known as Infra Red (below the red) because it was shown to have longer wavelength than visible light. [http://www.krysstal.com/spectrum.html]

27. Image Credit: http://imagine.gsfc.nasa.gov/science/toolbox/emspectrum1.html Johann Wilhelm Ritter (1776 - 1810) Image credit: http://coolcosmos.ipac.caltech.edu/cosmic_classroom/classroom_activities/ritter_bio.html In chemistry at that time there was a rumour that blue light was more efficient at initiating chemical change than red light. Ritter tried to measure the speed at which silver chloride broke down with different colours. He proved that blue light was indeed more efficient that red light. He was amazed, however, that the most vigorous reactions took place in the region beyond the violet where nothing could be seen. This new radiation was originally called Chemical Rays but is now called Ultra Violet (beyond the violet). Ultra Violet differs from visible light only in its wavelength which is shorter. [http://www.krysstal.com/spectrum.html]

28. Image Credit: http://imagine.gsfc.nasa.gov/science/toolbox/emspectrum1.html Heinrich Rudolf Hertz (1857 - 1894) Image credit: http://en.wikipedia.org/wiki/Heinrich_Hertz He set up electric circuits that produced oscillations and managed to produce electromagnetic radiation with a wavelength of 66cm (over a million times longer than light). This radiation could be picked up by other circuits set up quite a distance away. The new radiation was first called Hertzian Waves; this became Radiotelegraphic Waves after Marconi. We now call them Radio Waves . [http://www.krysstal.com/spectrum.html]

29. Image Credit: http://imagine.gsfc.nasa.gov/science/toolbox/emspectrum1.html Perry Spencer (1894 - 1970) invented the microwave oven In 1945, Percy Spencer was experimenting with a new vacuum tube called a magnetron while doing research for the Raytheon Corporation. He was intrigued when the candy bar in his pocket began to melt, so he tried another experiment with popcorn. When it began to pop, Spencer immediately saw the potential in this revolutionary process. In 1947, Raytheon built the first microwave oven, the Radarange . [http://science.howstuffworks.com/innovation/scientific-experiments/9-things-invented-or-discovered-by-accident2.htm] The scientists discovered the cosmic microwave background radiation. This radiation, which fills the entire Universe, is believed to be a clue to it's beginning, something known as the Big Bang. Arno Penzias and Robert Wilson

30. Image Credit: http://imagine.gsfc.nasa.gov/science/toolbox/emspectrum1.html Wilhelm Conrad Roentgen (1845 - 1923) On the night of 5 November 1895, he noticed a glow coming from a chemical called barium platinocyanide . This chemical glowed whenever the tube was on, even if he put cardboard between it and the tube. Roentgen went on to show that the glow was caused by a highly penetrating but invisible radiation given off by the tube. It passed through paper, thin sheets of metal, flesh. It could ionise gases and had wave properties like light but only much shorter wavelengths. The new radiation was called X-Rays because of their mysterious properties. Roentgen refused to patent the discovery or make any financial gain out of it but he was awarded the first ever Nobel Prize for Physics. [http://www.krysstal.com/spectrum.html] Image credit: http://www.two-views.com/article_Rontgen.html

31. Image Credit: http://imagine.gsfc.nasa.gov/science/toolbox/emspectrum1.html Villard discovered gamma radiation in 1900, while studying radiation emitted from radium . Villard knew that his described radiation was more powerful than previously described types of rays from radium, which included beta rays , first noted as "radioactivity" by Henri Becquerel in 1896, and alpha rays , discovered as a less penetrating form of radiation by Rutherford, in 1899. However, Villard did not consider naming them as a different fundamental type. Villard's radiation was recognized as being of a type fundamentally different from previously named rays, by Ernest Rutherford , who in 1903 named Villard's rays "gamma rays" by analogy with the beta and alpha rays that Rutherford had differentiated in 1899. [http://en.wikipedia.org/wiki/Gamma_ray] Paul Ulrich Villard (1860 - 1934) Image credit: http://en.wikipedia.org/wiki/Paul_Ulrich_Villard