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12.3 Properties of Waves. pp. 452 -458 Mr. Richter. Agenda. Warm-Up Review HW Notes: Types of Waves Wave Speed Waves and Energy. Objectives: We Will Be Able To…. Distinguish local particle vibrations from overall wave motion. Differentiate between types of waves.
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12.3 Properties of Waves pp. 452 -458 Mr. Richter
Agenda • Warm-Up • Review HW • Notes: • Types of Waves • Wave Speed • Waves and Energy
Objectives: We Will Be Able To… • Distinguish local particle vibrations from overall wave motion. • Differentiate between types of waves. • Apply the relationship among wave speed, frequency, and wavelength to solve problems. • Relate energy to amplitude.
Warm-Up: • How does sound travel from your mouth to a person’s ear? • Can you make sound travel faster? • Louder?
Mechanical vs. Non-Mechanical Waves • Mechanical wave: a wave that propagates through a deformable, elastic medium • medium: the material through which a disturbance travels • Non-mechanical waves: do not require a medium through which to pass • X rays, magnetic waves, visible light, radio waves, etc.
Pulse vs. Periodic Waves • Periodic wave: whenever the source of the wave’s motion is a periodic motion (repeated), a periodic wave is produced. • Pulse wave: a wave consisting of a single traveling pulse.
Transverse Waves • Particles of the medium move perpendicularly to the wave motion • For example: wave travels to the right as the particles of the Slinky move up and down. https://www.youtube.com/watch?v=UHcse1jJAto
Longitudinal Waves https://www.youtube.com/watch?v=aguCWnbRETU • when the particles of a medium vibrate parallel to the direction of the wave • also called a density wave or pressure wave
Transverse and Longtudinal Waves • https://www.youtube.com/watch?v=Rbuhdo0AZDU
Wave Speed • The speed of propagation of a mechanical wave depends on the medium through which the wave travels. • Some media are thicker or less flexible than others. • Think of sound traveling through water as opposed to traveling through air. • Speed of propagation of a mechanical wave is constant for any given medium. • Example: the speed of sound in air is always (roughly) 340 m/s.
Wave Speed • A wavelength is the displacement of a wave in one period of time. (How long is the wave for a complete cycle.) • If frequency is increased, wavelength must decrease.
Your Turn • The piano string tuned to middle C vibrates with a frequency of 264 Hz. Assuming the speed of sound in air is 343 m/s, find the wavelength of the sound waves produced by the string. • v = ƒλ • 343 m/s = 264 Hz * λ • λ=343/264 = 1.30 m
Waves and Energy • Energy transfers from adjacent particles across the medium. • Waves transfer the motion of matter without transferring the matter itself. • This often makes waves a more efficient method to transfer energy. • The larger the amplitude, the greater the energy transferred.
Wave Energy Commercial • Wave Energy
Wrap-Up: Did we meet our objectives? • Distinguish local particle vibrations from overall wave motion. • Differentiate between types of waves. • Apply the relationship among wave speed, frequency, and wavelength to solve problems. • Relate energy to amplitude.
Homework • p. 470 #24-28, 35