P5

-light is a type of electromagnetic wave.

-there are certain frequencies our eyes can see and they are called visible light.

-lower frequencies = more towards the redish side

-high frequencies= more towards blueish side.

-all electromagnet waves are transverse

-all electromagnetic waves in a vacuum travel at the speed of light= 3 Ă— 10^4 miles per second.

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-William Hershel discovered infrared by putting dark colored filters on his telescope to observe the sun. he noticed that the different colored filters heated up his telescope to different extents and wondered if the different colors could absorb different amounts of heat. therefor he used a prism to spilt white light into the colors and put a thermometer on each of them but beyond the red end of the spectrum where there was no visible light the thermometer got the hottest.

-ROY G BIV= red, orange, yellow, green, blue, indigo and violet.

-uses for the different types of waves=

  • visible light= light bulbs to emit light, ability to see, photography

  • infrared= security camera detection, heating up by radiation

  • microwaves= communication, heating up

  • radio waves= communication (radio waves are produced by oscillation)

  • ultraviolet= disinfect water by killing microorganisms.

  • Xray= used in medicine to take images of inside the body.

  • gamma rays= sterilize food, kill cancer cells, locates cancer cells

-dangers of the different types of waves=

  • infrared= damage to skin cells

  • UV= damage DNA and cells causing sunburn which can lead to skin cancer, can also damage eyes

  • x rays and gamma= mutations to the DNA and cause cancer