OBJECTIVE TLW, with 100% participation, differentiate between wavelengths of the electromagnetic spectrum, identify uses of each, and examine how these properties are imperative in obtaining information pertaining to the universe.

Brainpop: Electromagnetic Spectrum  Answer the 10 questions on your handout after watching the Brainpop video. Upon completing your Cornell Notes, you will finish the other side and submit for grading. This is due at the end of the period.

Electromagnetic Radiation Conceptual Physics    J. Beauchemin 2009

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

Anatomy of a Wave  Wavelength: the distance between the tops of two adjacent crests or bottom of two adjacent troughs  Crest: the highest point of a wave  Trough: the lowest point of a wave  Frequency: number of wavelengths that pass a given point in one second, measured in Hertz (Hz)  Amplitude: the maximum extent of a vibration or oscillation, measured from the position of equilibrium.

Anatomy of a Wave crest trough wavelength amplitude

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

Wave-particle Duality  Light can behave like a wave or like a particle  A “particle” of light is called a photon

Radio waves  Longest wavelength (lowest frequency) EM waves  Uses: TV broadcasting AM and FM broadcast radio Avalanche beacons Heart rate monitors Cell phone communication

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

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

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

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

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

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

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

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