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Waves. Chapter 10 Section 1 The Nature of Waves. Waves. The Nature of Waves slides 1-20 Wave Properties slides 21- 46 The Behavior of Waves slides 46 -97. Waves. A wave is a repeating disturbance or movement that transfers energy through it. Waves.
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Waves Chapter 10 Section 1 The Nature of Waves
Waves • The Nature of Waves slides 1-20 • Wave Properties slides 21- 46 • The Behavior of Waves slides 46 -97
Waves • A wave is a repeating disturbance or movement that transfers energy through it.
Waves • A wave is a repeating disturbance or movement that transfers energy through it. • Examples: • Microwaves • Radio waves • Sound waves • Ocean waves
Waves and Energy • A pebble falling into a pool causes a disturbance which transfers energy to the water molecules nearby which in turn pass the energy along to molecules that are next to them. A wave is formed that carries the energy along the surface of the water.
Do waves carry matter? • A boat on a lake may move up and down or even back and forth a little with a wave but is not carried to a different position. • The wave ONLY carries energy without moving matter.
How can you make a wave? • A wave will travel as long as there is both energy & a medium to carry it.
How can you make a wave? • A wave will travel as long as there is both energy & a medium to carry it. • Anything that moves up & down or back and forth is a vibrating movement. • Vibrations cause all waves.
Mechanical Waves • A medium is the matter through which a wave travels. It can be solid, liquid, or gas or a combination.
Mechanical Waves • A medium is the matter through which a wave travels. It can be solid, liquid, or gas or a combination. • Light and radio waves do not need a medium & can travel through space.
Mechanical Waves • A medium is the matter through which a wave travels. It can be solid, liquid, or gas or a combination. • Light and radio waves do not need a medium & can travel through space. • Waves that can only travel through a medium are called mechanical waves. • Transverse • Compressional
Mechanical Waves • Waves that can only travel through a medium are called mechanical waves. • Transverse- the matter in the medium moves at a right angle to the direction the wave travels; ex. Ocean wave • Compressional (longitudinal)- matter moves back and forth in the same direction that the wave travels ex. spring
Mechanical Waves Transverse Wave Compressional Waves
How do sound waves move? • Sounds waves are compressional waves which travel through air, water, and wood. When the sound wave reaches your ear, it causes your eardrum to vibrate, sending signals to your brain which you understand as sound.
How do water waves move? • Water waves are a combination of transverse & compressional waves. The water moves up & down & back & forth ending up where it began.
How do ocean waves move? • Wind blowing across the ocean surface causes most ocean waves to form.
How do ocean waves move? • Wind blowing across the ocean surface causes most ocean waves to form. • Size of the wave depends on: • Speed of the wind • Length of time the wind blows • How far it travels over the water
What are seismic waves? • Seismic waves are a combination of transverse & compressional waves that carry energy outward and cause an earthquake.
Mechanical Waves Transverse Waves Compressional waves How they move How they move example example
Mechanical Waves Transverse Waves Compressional waves How they move How they move the matter in the medium moves at a right angle to the direction the wave travels matter moves back and forth in the same direction that the wave travels example example Spring or slinky, sounds Ocean waves
Wave Properties Chapter 10 Section 2
Parts of a Wave • Crest • Trough • Rarefaction
Parts of a Wave • Crest – high point of a transverse wave • Trough – low point of a transverse wave • Rarefaction – area where the medium is more spread out
Compressional Wave • Rarefaction – area where the medium is more spread out
Parts of a Wave • Wavelength- distance b/w one point on a wave and the nearest point just like it.
Human Hearing • Only hear sounds that have wavelengths with measures between a few cm and about 15 m.
Frequency and Period • Frequency- number of wavelengths that pass by a point each second, expressed in Hz (hertz) ex. Choosing radio station.
Frequency and Period • Frequency- number of wavelengths that pass by a point each second, expressed in Hz (hertz) ex. Choosing radio station. • Period- amount of time it takes one wavelength to pass a point, measured in seconds.
How are frequency & wavelength related? • As the frequency of waves increases, their wavelength decreases
Wave Speed • Light waves travel through gases much faster than sound waves.
Wave Speed • Light waves travel through gases much faster than sound waves. • The speed of a wave depends on the medium it is traveling through.
Wave Speed • Light waves travel through gases much faster than sound waves. • The speed of a wave depends on the medium it is traveling through. • Sound waves (compression) usually travel faster than light waves through liquids and solids.
Wave Speed • Light waves travel through gases much faster than sound waves. • The speed of a wave depends on the medium it is traveling through. • Sound waves (compression) usually travel faster than light waves through liquids and solids. • Sound waves usually travel faster in a material if the temperature of the material is increased.
How do you calculate wave speed? • Calculate speed by multiplying its frequency times its wavelength. The Greek letter lambda (λ) represents wavelength, f is frequency, and v represents the speed of the wave.
How do you calculate wave speed? • Calculate speed by multiplying its frequency times its wavelength. The Greek letter lambda (λ) represents wavelength, f is frequency, and v represents the speed of the wave. • Speed (m/s) = frequency (Hz) X wavelength ( in m) or v = f λ
How do you calculate wave speed? • Calculate speed by multiplying its frequency times its wavelength. The Greek letter lambda (λ) represents wavelength, f is frequency, and v represents the speed of the wave. • Speed (m/s) = frequency (Hz) X wavelength ( in m) or v = f λ • What is the speed of a sound wave that has a frequency of 150 Hz and a wavelength of 0.00002 mm? Show your work.
How do you calculate wave speed? • What is the speed of a sound wave that has a frequency of 150 Hz and a wavelength of 0.00002 mm? Show your work. • F = 150 Hz λ = 0.00002 mm
How do you calculate wave speed? • What is the speed of a sound wave that has a frequency of 150 Hz and a wavelength of 0.00002 mm? Show your work. • F = 150 Hz λ = 0.00002 mm • V = f λ =
How do you calculate wave speed? • What is the speed of a sound wave that has a frequency of 150 Hz and a wavelength of 0.00002 mm? Show your work. • F = 150 Hz λ = 0.00002 mm • V = f λ = 150 Hz X 0.00002 mm
How do you calculate wave speed? • What is the speed of a sound wave that has a frequency of 150 Hz and a wavelength of 0.00002 mm? Show your work. • F = 150 Hz λ = 0.00002 mm • V = f λ = 150 Hz X 0.00002 mm • V = .003 mm/s
Amplitude and Energy • Amplitude – measure of the energy that a wave carries. The greater the amplitude, the more energy the wave carries.
Amplitude and Energy • Amplitude – measure of the energy that a wave carries. The greater the amplitude, the more energy the wave carries. • Compressional waves amplitude depends on how tightly the medium is pushed together at the compressions.
Amplitude and Energy • Amplitude – measure of the energy that a wave carries. The greater the amplitude, the more energy the wave carries. • Compressional waves amplitude depends on how tightly the medium is pushed together at the compressions. • Transverse waves amplitude = distance from the crest or trough of the wave to the rest position
Wavelength Energy Frequency Properties of waves Period Amplitude Wave speed
The Behavior of Waves Chapter 10 Section 3
Reflection • Wave reflection happens when a wave strikes an object or surface and bounces off of it.
Reflection • Wave reflection happens when a wave strikes an object or surface and bounces off of it. • All types of waves, including sound, water, and light waves, can be reflected.
How do light waves reflect? • Light waves strike canal houses in Amsterdam; then the reflected waves strike water in the canal and bounce off creating this image captured by the camera.
Law of Reflection • The light beam striking the mirror is called the incident beam.