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Warm-up Exercise. Log into the iRespond system. W hat do the following three items have in common? A zipper A shark A comb. S8P4: Students will explore the wave nature of sound and electromagnetic radiation. Identify the characteristics of electromagnetic and mechanical waves.
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Warm-up Exercise Log into the iRespond system. What do the following three items have in common? A zipper A shark A comb
S8P4: Students will explore the wave nature of sound and electromagnetic radiation Identify the characteristics of electromagnetic and mechanical waves. Describe how the behavior of light waves is manipulated causing reflection, refraction diffraction, and absorption. Explain how the human eye sees objects and colors in terms of wavelengths. Describe how the behavior of waves is affected by medium (such as air, water, solids).
Essential Question What are some everyday uses of electromagnetic radiation (or waves)?
Electromagnetic Radiation
Characteristics of Electromagnetic Radiaiton Aa. Produced by the motion of electrically charged particles moving back and forth.
Characteristics of Electromagnetic Radiaiton • The charged particles are surrounded by: • Electric fields • Magnetic fields
Characteristics of Electromagnetic Radiaiton • Transverse waves • Do not require a medium
Characteristics of Electromagnetic Radiaiton d. All electromagnetic waves Travel at 300,000,000 m/s in a vacuum Nothing travels faster than the speed of light!
Characteristics of Electromagnetic Radiaiton e. Travels slower when passing through a medium
Duel Nature of Electromagnetic Radiation • Particle nature • Travels in bundles of energy • Bundles act like small particles • Called photons
Duel Nature of Electromagnetic Radiation
Duel Nature of Electromagnetic Radiation • Wave nature • All electromagnetic waves travel at the same speed • Frequency and wavelength are used to classify the waves in the electromagnetic spectrum
Electromagnetic Spectrum The electromagnetic spectrum is the complete range of electromagnetic waves placed in order of increasing frequency.
Electromagnetic Spectrum • As the frequency increases: • Wavelength decreases • Photon penetrating energy increases
Radio Waves • Uses: Communication (telephones, pagers, radio transmission, global positioning system • Long wavelength and Low frequency • Lowest Photon energy
Microwaves • Uses: Cooking, cellular phones, radar • Long wavelength and Low frequency • Lower Photon energy
Infrared Radiation • Wavelength is only a little longer than visible light • Uses – Remote controls, thermal energy transfer (radiant energy) including night vision, infrared photography, locating tumors • (Remember all living object give off infrared radiation.)
Visible Radiation • Only wavelengths that can be detected by the human eye • Use – allow humans to see
Ultraviolet Radiation • Higher frequency and shorter wavelength than visible radiation • Uses– Produces vitamin D in human skin and can be used to kill bacteria and viruses (sterilize equipment) • Warning! – too much can cause skin cancer; Ozone in the atmosphere blocks it
X-rays • Higher frequency and photon energy – greater penetrating power • Uses: X-ray pictures; rays will penetrate soft matter like skin and muscle, but it is absorbed by the harder bones
Gamma Rays • Highest frequency -- greater penetrating power • Uses: destroy human cells and can be used to kill cancerous cells
Pop Tart Review Get ready!
Pop Tart Review What produces electromagnetic radiation?
Pop Tart Review What type of wave is electromagnetic radiation?
Pop Tart Review Name a wave that can travel faster than electromagnetic radiation?
Pop Tart Review What is a photon?
Pop Tart Review Name the longest electromagnetic wave.
Pop Tart Review What name do we give to all the electromagnetic waves arranged from longest wavelength to shortest wavelength?
Pop Tart Review Name electromagnetic wave used to see a child in a burning house.