Download - Unit 4 Section 2 Notes Types of Waves
Types of Waves
What is a Wave?Wave:
A disturbance that carries energy through matter or space.
Examples of Waves:Sound you hear from your headphones
EarthquakesRipples in a pond
MediumsA wave is not made of matter, but involves
the movement of matter. Most waves travel through a medium. Medium: the matter through which a wave
travels. Examples: Sound you hear from your headphones: AirEarthquakes: EarthRipples in a pond: Water
Types of WavesMechanical Waves:
Most waves are mechanical waves
They require a medium (like water or air) to travel through.
Types of WavesElectromagnetic
Waves:Do NOT require a
medium to travel through
Made of changing electric and magnetic fields, which radiate at the speed of light (3x108m/s)
This shows the wave traveling along one line, but it actually fills space.
Electromagnetic WavesAnything that is part of the electromagnetic
spectrum is an electromagnetic wave. That includes:Radio wavesMicrowavesInfraredVisible lightUltraviolet lightX-RaysGamma Rays
Types of WavesMechanical Waves Electromagnetic
Waves
Waves do WorkWe know that
waves carry energy because they can do work:Examples:
Water waves can do work on a leaf or a boat
Sound waves can do work on your eardrum
Waves do WorkThe larger the wave, the more
energy it carries.Example:
A cruise ship moving through the ocean may create waves big enough to move a fishing boat up and down a few meters.
Characteristics of WavesIf you go to a rock
concert and stand next to the speakers, the sound waves may damage your ears. But if you stand 100 m away, the sound of the rock band is harmless. Why?
As waves travel outward, the spherical wave fronts get bigger, so the energy spreads out over a larger area.
Transverse and Longitudinal WavesWaves are classified according to the
direction in which particles in the medium move as a wave passes by; they can either move up and down or back and forth.
They are classified as either transverse or longitudinal.
Transverse WavesTransverse wave: wave in which wave motion
is perpendicular (up and down) to particle motion. Examples:
A crowd doing “the wave”; individual people move up and down, but the motion travels around the stadium
Electromagnetic waves; electric and magnetic fields are perpendicular to each other
Motion of particles in a transverse waveWave travels to the right:
Wave motion
Particle motion
Longitudinal Waves (Compression Wave)Longitudinal waves: Waves in which wave motion
is parallel to the particle motion. Example: Sound waves; as they move through the air,
molecules in the air move backward and forward, parallel to the direction the sound waves travel.
Parts of WavesTransverse Waves Longitudinal WavesCrests: high points of
transverse wavesTroughs: low points of
transverse waves
Compressions: crowded areas of longitudinal waves
Rarefactions: stretched out areas of longitudinal waves
Surface WavesSome waves are not simply transverse or
longitudinal:Surface Waves: Waves that move both
perpendicular and parallel to the direction of wave motion. Example: Waves on the ocean or
swimming poolThis type of wave also occurs at the
boundary between 2 different mediums, like water and air.
Surface Waveshttp://www.acs.psu.edu/drussell/Demos/
waves/wavemotion.html http://www.teachersdomain.org/asset/
lsps07_int_waves/
Diagram of Types of Waves
Simple Harmonic MotionA vibration that can
keep on going without any interference.
Dampened Harmonic Motion:A vibration that
fades out as energy is transferred from one object to another