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Waves can be…
• Water waves• Sound waves• Light waves• Earthquake waves• Waves in a slinky• Stadium waves
Waves transmit energy…
…waves do not move matter (objects) from one place to another like wind or water currents.
Instead, energy moves from place to place through waves…
…if matter moves, it vibrates in an up and down / side to side motion, a forward and back motion, or both (circular).
Wave – Any disturbance that transmits energy through matter or empty space.
Vibration
A vibration is a complete back and forth motion of matter.
•It is the source or beginning and waves travel outward in all directions from this source.
Sound waves travel outward in all directions.
Sunlight (radiation) travels outward in all directions.
Earthquake waves travel outward in all directions.
Medium
A Medium is a substance through which a wave can travel such as air, water, rock …
Electromagnetic Waves
• Waves that do not require a medium.
• Light travels by electromagnetic waves called radiation.
• Light (radiation) can travel through the emptiness of space (no medium) from the Sun to the Earth.
• Light (radiation) can also travel through many types of matter (medium) like air, water, glass…
Electromagnetic Radiation
The different types of electromagnetic energy
Electromagnetic spectrum
A chart that organizes the types of electromagnetic energy in order by wavelength.
Visible light spectrum
What warms the Earth?• Nuclear Reactions in the Sun produce the
energy that is released in all directions as Electromagnetic radiation (light energy).
• This light energy travels through the emptiness of space as electromagnetic radiation and some of it reaches the Earth’s surface.
• When this light energy strikes the Earth’s surface, some of it is reflected off and some of it is absorbed then transferred into heat energy.
Mechanical Waves
• Waves that require a medium.
• Sound travels by mechanical waves
• Sound cannot travel through the emptiness of space (no medium).
• Sound waves need air, water, glass or some other matter to vibrate and thus travel through.
Longitudinal Waves
Transverse Waves
Waves in which the particles of the medium move in the same direction as the direction the wave is traveling.
Waves in which the particles of the medium move perpendicular to the direction the wave is traveling.
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Transverse Waves
Waves in which the particles of the medium move perpendicular to the direction the wave is traveling.
Crest
Trough Direction of travel
Crest & Trough
• Crest – The highest point of a transverse wave
• Trough - The lowest point of a transverse wave
Longitudinal Waves
Waves in which the particles of the medium move in the same direction as the direction the wave is traveling.
Compressions Rarefactions
Direction of travel
Compression & Rarefaction
• Compression – A part of a longitudinal wave where the particles are crowded together
• Rarefaction - A part of a longitudinal wave where the particles are spread apart
Surface waves • Form when a transverse wave and a
longitudinal wave combine.• The particles of the medium move both
perpendicular to and in the same direction as the direction the wave is traveling resulting in a circular motion.
• Water waves are surface waves.
Direction of travel
Circular motion
Seismic Waves
• Earthquake waves are Seismic waves. • The medium is the Rock of the Earth.
Waves are characterized by…
• Amplitude
• Wavelength
• Frequency
Waves are characterized by…• Amplitude – The maximum distance that
the particles of the wave’s medium vibrate from their rest position.
• Wavelength – The distance from any point on a wave to an identical point on the next wave.
• Frequency – The number of waves produced in a given amount of time.
AmplitudeThe maximum distance that the particles of the
wave’s medium vibrate from their rest position.
Changing Amplitude
Large amplitude
Small amplitude
Small Amplitude
Large Amplitude
Frequency The number of waves produced in
a given amount of time.
High frequency &
Short wavelength
Low frequency & Long wavelength
Wave Reflection
The bouncing back of a ray of light, sound or heat when the ray hits a surface that it does not go through.
Wave Refraction
The bending of a wave as the wave passes between two substances in which the speed of the wave differs.
Refraction - thick mug illusion by Paul G Hewitt - YouTube
Wave Diffraction
A change in the direction of a wave when the wave finds an obstacle or an edge, such as an opening.
Wave InterferenceWhen the crest line up with crests, the resulting wave is increased (constructive interference)
When the crests line up with troughs, the resulting wave is decreased (destructive interference)Wave Interference – YouTube Beats (acoustics) - YouTube
Standing Wave
A pattern of vibration that simulates a wave that is standing still.
Creating Standing Waves – YouTube
Standing Wave River Surfing at Waimea Bay - YouTube
Standing Waves Generated by String Vibration - YouTube
Resonant frequency
The frequency at which standing waves are made.
Resonance
• breaking a wine glass using resonance – YouTube
• Girl breaks glass with voice – YouTube• Myth busters Breaking Glass with your voice!! pa
rt 2 - YouTube
Resonance
• Wine Glass Music – YouTube
• Glass music-Dance of the sugar plum fairy-Tchaikovsky – YouTube
Resonance – sympathetic vibrations of tuning forks
• Resonance – YouTube (tuning forks)
• interference of sound beats - YouTube
• Car on the Tacoma Narrow Bridge - YouTube• Tacoma Bridge – YouTube
Sonic Boom
Sonic Boom - YouTube
If an object can travel faster than the speed of sound, it will catch up to its own sound. The sound waves will compress and make a large “BOOM”.
Link to …
AP Physics Chapter 15 Study Guide.url
Wave animation website http://www.kettering.edu/~drussell/demos.html
http://www.acoustics.org/press/151st/Lindwall.html
Wave TerminologyWave – Any disturbance that transmits energy through matter or empty space
Medium – a substance through which a wave can travel
Mechanical Wave – Waves that need a medium (substance)
Electromagnetic Wave - Waves that transfer energy without going through a medium
Transverse Wave – Waves in which the particles of the medium move perpendicular to the direction the wave is traveling
Longitudinal Wave - Waves in which the particles of the medium move in the same direction as the direction the wave is traveling
Surface Wave – Waves in which the particles of the medium move both perpendicular to and in the same direction as the direction the wave is traveling resulting in a circular motion
Perpendicular – At right angles to
Crest – The highest point of a transverse wave
Trough - The lowest point of a transverse wave
Compression – A part of a longitudinal wave where the particles are crowded together
Rarefaction - A part of a longitudinal wave where the particles are spread apart
Wave TerminologyWave – Any disturbance that transmits energy through matter or empty space
Medium – a substance through which a wave can travel
Mechanical Wave – Waves that need a medium (substance)
Electromagnetic Wave - Waves that transfer energy without going through a medium.
• Transverse Wave – Waves in which the particles of the medium move perpendicular to the direction the wave is traveling.
• Longitudinal Wave - Waves in which the particles of the medium move in the same direction as the direction the wave is traveling.
• Surface Wave – Waves in which the particles of the medium move both perpendicular to and in the same direction as the direction the wave is traveling resulting in a circular motion
• Perpendicular – At right angles to
• Crest – The highest point of a transverse wave
• Trough - The lowest point of a transverse wave
• Compression – A part of a longitudinal wave where the particles are crowded together
• Rarefaction - A part of a longitudinal wave where the particles are spread apart
Waves (1-2) Terms and Definitions
• Amplitude • Wavelength • Frequency • Hertz • Wave Speed
• Amplitude – The maximum distance that the particles of the wave’s medium vibrate from their rest position.
• Wavelength – The distance from any point on a wave to an identical point on the next wave.
• Frequency – The number of waves produced in a given amount of time.
• Hertz – The units used when measuring wave frequency (number of waves per second).
• Wave Speed – The speed at which a wave travels through a medium.
Waves (1-3) Terms and Definitions
• Reflection• Echo• Refraction• Diffraction• Interference• Constructive Interference• Destructive Interference• Standing Wave• Resonant Frequencies• Resonance
• Reflection – The bouncing back of a ray of light, sound, or heat when the ray hits a surface that it does not go through.
• Echo – A reflected sound wave
• Refraction – The bending of a wave as the wave passes between two substances and the speed of the wave changes.
• Diffraction – The bending of a wave around an obstacle or through an opening.
• Interference – The combination of two or more waves that result in a single wave.
• Constructive Interference – When two waves overlap and their energy is combined (crests line up with crests) to produce a wave with a larger amplitude and more energy than the original waves.
• Destructive Interference - When two waves overlap and their energy is canceled by the other wave (crests line up with troughs) to produce a wave with a smaller amplitude and less energy than the original waves.
• Standing Wave – A wave produced by both constructive and destructive interference that appears to be standing still.
• Resonant Frequencies – The frequency at which standing waves are made.
• Resonance – A phenomenon that occurs when two objects naturally vibrate at the same frequency: the sound produced by one object causes the other object to vibrate.
• Reflection – The bouncing back of a ray of light, sound, or heat when the ray hits a surface that it does not go through.
• Echo – A reflected sound wave
• Refraction – The bending of a wave as the wave passes between two substances and the speed of the wave changes.
• Diffraction – The bending of a wave around an obstacle or through an opening.
• Interference – The combination of two or more waves that result in a single wave.
• Constructive Interference – When two waves overlap and their energy is combined (crests line up with crests) to produce a wave with a larger amplitude and more energy than the original waves.
• Destructive Interference - When two waves overlap and their energy is canceled by the other wave (crests line up with troughs) to produce a wave with a smaller amplitude and less energy than the original waves.
• Standing Wave – A wave produced by both constructive and destructive interference that appears to be standing still.
• Resonant Frequencies – The frequency at which standing waves are made.
• Resonance – A phenomenon that occurs when two objects naturally vibrate at the same frequency: the sound produced by one object causes the other object to vibrate.
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