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Electromagnetic Spectrum

Unit 9 - Light & Sound

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Lesson 3: Questions

  • How do the waves in the EM spectrum differ from each other?

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  • How do we utilize each type of wave in the EM spectrum?

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Vocabulary

Define the following vocabulary words:

  • Light
  • Electromagnetic spectrum
  • Radio waves
  • Infrared
  • Visible light
  • Ultraviolet
  • X-ray
  • Gamma ray

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Video: Electromagnetic Spectrum

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Light

Light Energy - Energy that travels in the form of waves.

  • Example: Sunlight

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Light

Light - a transfer of energy that creates a visual sensation

  • Light is a transverse wave

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Light

  • Light does not need a medium to travel

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Light

Frequency - the number of waves passing a point per second

  • Units: Hertz (Hz)
  • Frequency describes the color/type of light

HIGH frequency = Ex. UV Light Waves

LOW frequency = Ex. Radio Waves

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Light

Light belongs to a larger category of waves called the electromagnetic spectrum.

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Electromagnetic spectrum - the full range of visible and invisible waves.

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Light

The electromagnetic spectrum includes:

  • Radio waves
  • Microwaves
  • Infrared waves (IR)
  • Visible light
  • Ultraviolet waves (UV)
  • X-Rays
  • Gamma rays

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All waves travel 300,000 km/s = SPEED OF LIGHT

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Electromagnetic Spectrum

Wavelength

Frequency

Energy

Radio

(Microwaves, Radio, TV)

Infrared

(IR)

Ultraviolet

(UV)

X-Ray

Gamma

Visible

Light

R

O

Y

G

B

I

V

Wavelength

Frequency

Energy

LONG

LOW

LOW

SHORT

HIGH

HIGH

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Electromagnetic Spectrum

Radio Waves - used in radio and TV, microwave ovens, and radar.

  • Amplitude modulation (AM)

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  • Frequency modulation (FM)

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Electromagnetic Spectrum

Microwaves - the shortest-wavelength radio waves

  • Cooking and reheating food

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Radar Waves - waves reflect off objects and return back towards the source they came from

  • Doppler Effect

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Television Waves - carry information for pictures and sound

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Electromagnetic Spectrum

Infrared Light (IR) - source of heat and used to discover heat differences

  • Warming lamps
  • Thermograms

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Electromagnetic Spectrum

Video: Infrared

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Electromagnetic Spectrum

Visible Light - only light visible to humans

  • Color (ROYGBIV)

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Electromagnetic Spectrum

Ultraviolet Light - higher frequency than violet

  • Sunlight (source of Vitamin D)
    • Excessive exposure damages skin
  • Can disinfect air/bacteria

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Electromagnetic Spectrum

X-Rays - makes pictures of the inside of solid objects

  • X-Ray technology

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Electromagnetic Spectrum

Gamma Rays - high energy waves with the greatest penetrating ability of all waves.

  • Radiation therapy

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Additional Video Resources

Click on the link below to view videos on each of the electromagnetic spectrum waves.

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Click here to learn more