Upload
delphia-banks
View
215
Download
0
Tags:
Embed Size (px)
Citation preview
PHYSICAL SCIENCEPHYSICAL SCIENCE
WavesWaves
Part 1: Types of WavesPart 1: Types of Waves
Section 1 Types of Waves Section 1 Types of Waves ObjectivesObjectives
Recognize that waves transfer energy.Recognize that waves transfer energy. Distinguish between mechanical waves Distinguish between mechanical waves
and electromagnetic waves.and electromagnetic waves. Explain the relationship between particle Explain the relationship between particle
vibration and wave motion.vibration and wave motion. Distinguish between transverse waves and Distinguish between transverse waves and
longitudinal waves.longitudinal waves.
What is a WaveWhat is a Wave
A wave is a disturbance that transmits A wave is a disturbance that transmits energy through matter or space.energy through matter or space.
If a wave travels through matter, that If a wave travels through matter, that matter is called the medium.matter is called the medium. The medium for an earthquake wave is earthThe medium for an earthquake wave is earth The medium for a ripple in a pond is waterThe medium for a ripple in a pond is water The medium for sound is airThe medium for sound is air
Mechanical waves are waves that require Mechanical waves are waves that require a medium through which to travel.a medium through which to travel.
What is a WaveWhat is a Wave
An electromagnetic wave is a wave An electromagnetic wave is a wave caused by a disturbance in electric and caused by a disturbance in electric and magnetic fields and that does not require a magnetic fields and that does not require a medium.medium.
Electromagnetic waves are also known as Electromagnetic waves are also known as light waves, of which, visible light is only a light waves, of which, visible light is only a small part.small part.
Radio waves, microwaves, X-rays, and Radio waves, microwaves, X-rays, and ultraviolet waves are all types of light.ultraviolet waves are all types of light.
Properties of WavesProperties of Waves
Type of Type of WaveWave
MechanicalMechanical ElectromagneticElectromagnetic
FormForm LongitudinalLongitudinal TransverseTransverse Modeled as Modeled as TransverseTransverse
MediumMedium Solids, liquids, and Solids, liquids, and gasesgases
Solids and liquidsSolids and liquids None requiredNone required
Travel asTravel as Compressions and Compressions and rarefactions in matterrarefactions in matter
Back-and-forth (or Back-and-forth (or up-and-down) up-and-down) movement in movement in mattermatter
Oscillating electric Oscillating electric and magnetic fieldsand magnetic fields
ExamplesExamples Sound waves, some Sound waves, some earthquake wavesearthquake waves
Water waves, rope Water waves, rope waves, some waves, some earthquake wavesearthquake waves
Visible light waves, Visible light waves, radio waves, X-raysradio waves, X-rays
What is a WaveWhat is a Wave
Energy is the ability to do work.Energy is the ability to do work. Waves carry energy because they can do Waves carry energy because they can do
work.work. A cork that bobs on the water top is A cork that bobs on the water top is
evidence of work done on that cork as it is evidence of work done on that cork as it is moved by the wave that passes through it.moved by the wave that passes through it.
Sound waves can do work on the eardrum Sound waves can do work on the eardrum and light waves can do work on the retina and light waves can do work on the retina of the eye.of the eye.
What is a WaveWhat is a Wave
The bigger a wave is, the more energy it carries.The bigger a wave is, the more energy it carries. Energy may spread out as waves travel.Energy may spread out as waves travel.
Sound coming from a speaker seems to be less Sound coming from a speaker seems to be less intense as you move farther awayintense as you move farther away
Ripples from a stone being tossed in a pond spread Ripples from a stone being tossed in a pond spread farther out and progressively become less intensefarther out and progressively become less intense
As energy moves out it travels in wave fronts As energy moves out it travels in wave fronts which increase in size causing them to spread which increase in size causing them to spread the energy out over a larger area.the energy out over a larger area.
Vibrations and WavesVibrations and Waves
Most waves are caused by a vibrating object.Most waves are caused by a vibrating object. For example, when you speak, vocal cords in For example, when you speak, vocal cords in
your throat move back and forth causing the air your throat move back and forth causing the air in your throat to vibrate.in your throat to vibrate.
The vibrations create sound waves that travel The vibrations create sound waves that travel out and eventually strike our eardrums.out and eventually strike our eardrums.
In the inner ear, the vibrations trigger certain In the inner ear, the vibrations trigger certain frequency specific sensory cells that send frequency specific sensory cells that send impulses to the brain that are interpreted as impulses to the brain that are interpreted as sound.sound.
Anatomy of the EarAnatomy of the Ear
Transverse and Longitudinal Transverse and Longitudinal WavesWaves
Waves are often classified by the direction that Waves are often classified by the direction that the particles in the medium move as the wave the particles in the medium move as the wave passes by.passes by.
A transverse wave is a wave that causes the A transverse wave is a wave that causes the particles of the medium to vibrate perpendicular particles of the medium to vibrate perpendicular to the direction that the wave travels.to the direction that the wave travels. A transverse wave may be modeled by snapping a A transverse wave may be modeled by snapping a
jump rope up and watching the wave travel down the jump rope up and watching the wave travel down the rope horizontally as the particles that make up the rope horizontally as the particles that make up the rope move verticallyrope move vertically
Light also travels as a transverse waveLight also travels as a transverse wave
Transverse and Longitudinal Transverse and Longitudinal WavesWaves
A longitudinal wave is a wave that causes A longitudinal wave is a wave that causes the particles of the medium to vibrate the particles of the medium to vibrate parallel to the direction the wave travels.parallel to the direction the wave travels. A spring is useful for demonstrating a A spring is useful for demonstrating a
longitudinal wave as energy passes through longitudinal wave as energy passes through it, the metal that makes up the spring vibrates it, the metal that makes up the spring vibrates in the same direction as the wave travelsin the same direction as the wave travels
Sound also travels in longitudinal wavesSound also travels in longitudinal waves
Transverse and Longitudinal Transverse and Longitudinal WavesWaves
Ocean WavesOcean Waves
Waves on the ocean or in a pool are Waves on the ocean or in a pool are surface waves.surface waves.
Surface waves occur on the boundary Surface waves occur on the boundary between two different mediums.between two different mediums.
The particles in a surface wave move both The particles in a surface wave move both perpendicular and parallel to the direction perpendicular and parallel to the direction of the wave motion.of the wave motion.
Surface WavesSurface Waves
ReferencesReferences Anatomy of the Ear - Anatomy of the Ear -
http://www.yungmd.com/images/info_ear_diagrahttp://www.yungmd.com/images/info_ear_diagram.jpgm.jpg
Sound Wave - Sound Wave - http://www.uq.edu.au/_School_Science_Lessonhttp://www.uq.edu.au/_School_Science_Lessons/26.1.1z.GIFs/26.1.1z.GIF
Electromagnetic Spectrum - Electromagnetic Spectrum - http://universe.nasa.gov/be/library/EM_Spectrumhttp://universe.nasa.gov/be/library/EM_Spectrum3-new.jpg3-new.jpg
Transverse and Longitudinal Waves - Transverse and Longitudinal Waves - http://www.itsscience.com/waves/waves.jpghttp://www.itsscience.com/waves/waves.jpg
ReferencesReferences
Direction of Particle Motion - Direction of Particle Motion - http://www.qicomposites.com/images/fig.2.http://www.qicomposites.com/images/fig.2.jpgjpg
Surface Wave - Surface Wave - http://www.pa.uky.edu/~shlosman/anim/suhttp://www.pa.uky.edu/~shlosman/anim/surface_water_waves.gifrface_water_waves.gif