1 WAVES

Recognize that all waves transfer energy. 2 Recognize that all waves transfer energy. Explain the phenomena of reflection, refraction, interference, & diffraction. Relate frequency & wavelength to the energy of different types of electromagnetic waves & mechanical waves. Relate the speed of sound to different mediums. Explain the Doppler Effect in terms of everyday interactions. Compare and contrast the characteristics of electromagnetic and mechanical (sound) waves.

3 Waves Waves are disturbances that carry energy through matter or space. Clip Waves can be visible or invisible evidence of energy transfer. The material does not actually travel with the wave….. only the energy is carried.

Types of Waves Two types of waves: 4 Two types of waves: Mechanical Non-Mechanical Mechanical: waves need a medium in order to travel. Examples: Sound, water Non-mechanical: waves do not need a medium to travel. Examples: light, gamma waves, microwaves, x-rays

Mechanical Waves A medium is the material a wave travels through 5 Mechanical Waves Waves that require a medium to travel. A medium is the material a wave travels through Sound and water. Light waves are NOT Mechanical Waves.

Transverse waves Water, light Longitudinal waves sound 6 Ways that waves travel Transverse waves Water, light Longitudinal waves sound

Transverse Waves Transverse waves are UP & DOWN movements. 7 Transverse Waves Transverse waves are UP & DOWN movements. The displacement of individual particles is perpendicular (at right angles) to the direction of the wave. EX: water waves, radio waves (all EM waves)

Describing a Transverse Wave 8 Describing a Transverse Wave

The higher the amplitude, the more energy the wave is carrying 9 amplitude The higher the amplitude, the more energy the wave is carrying In a longitudinal wave- it’s how tight the compressions are

Frequency & Wavelength 10 Wavelength Distance between to identical points on adjacent waves. Meters As the wavelength decreases the frequency increases λ Frequency Number of waves per second Hertz

Movement of a Transverse Wave 11 9 Movement of a Transverse Wave CLIP

Remember: Energy is transferred ----NOT THE MATTER!-- 12 Example - Water Remember: Energy is transferred ----NOT THE MATTER!--

Longitudinal Waves 13 Longitudinal waves are a series of PUSHES & PULLS in which the motion of the medium is in the same direction as the wave Ex. Sound Waves

Characteristics of a Longitudinal (Compressional) Wave 14 Characteristics of a Longitudinal (Compressional) Wave

Parts of a Longitudinal wave 15 Parts of a Longitudinal wave Compressions & Rarefactions Rarefaction is a place where the atmospheric pressure is lowest.

Speed of a wave ν = f λ ν is the velocity (m/s) 16 Speed of a wave ν = f λ ν is the velocity (m/s) f is the frequency (hertz) λ is the wavelength (m) The speed of a mechanical waves is constant for any given medium.. The speed of a wave changes as it moves through different media

Wave interactions with matter 17 Wave interactions with matter Reflection occurs when a wave hits another wave or object that it cannot pass through and bounces back.

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19 Diffraction occurs when a wave passes through an opening and spreads out Diffraction is a wave phenomenon that is dependent on wavelength Light waves bend as they pass by the edge of a narrow aperture or slit 

20 Constructive Interference occurs when two or more waves hit the same point and combine to produce a larger single wave. Destructive Interference occurs when two or more waves hit the same point and combine to produce a smaller single wave.

Constructive Interference

Constructive Interference Clip Constructive Interference Destructive Interference