Presentation on theme: "WAVES c lick. WHAT IS A WAVE? ·a disturbance ·created by a source ·travels through a medium A ripple forms when raindrops hit the pond. What is the source?"— Presentation transcript:
WHAT IS A WAVE? ·a disturbance ·created by a source ·travels through a medium A ripple forms when raindrops hit the pond. What is the source? What is the medium? (move the green dot here to reveal answer)
Waves c lick for video ·Waves are oscillations that carry energy and information from one place to another. ·Examples of waves: light, sound, electricity in a wire, cell phone transmissions, ripple in a pond ·Two types of waves: transverse and longitudinal
Transverse Waves c lick ·Transverse wave: has its oscillations perpendicular to the direction of the wave. The wave moves left to right and the oscillation moves up and down ·Ocean waves are transverse waves
Longitudinal Wave c lick ·Longitudinal wave: has oscillations in the same direction the wave moves. ·Sound is a longitudinal wave
In which direction is the wave moving? In which direction are the people moving? TRANSVERSE WAVES Animation courtesy of Dr. Dan Russell, Kettering University people motion wave motion particle motion is perpendicular to wave motion (move the green dot here to reveal answer)
In which direction is the wave moving? In which direction are the particles moving? LONGITUDINAL WAVES Animation courtesy of Dr. Dan Russell, Kettering University (move the green dot here to reveal answer) wave motion particle motion is parallel to wave motion
Use the eras er to reve al the defi nitio ns Pu ll Types of Waves Longitudinal: Transverse: A wave that is perpendicular to the direction it is moving A wave that is parallel to the direction it is moving Can you use a slinky to demonstrate both types of waves? http://mattogno.com/MattognoGirls/wp- content/uploads/2008/11/slinky2.jpg
PARTS OF A TRANSVERSE WAVE amplitude crest trough wavelength
PARTS OF A LONGITUDINAL WAVE compression rarefaction wavelength
Click the buttons to reveal the properties Pu ll Properties of Waves Wavelength is the distance from one point to the next point in the cycle Crest Trough Amplitude is the amount the wave is displaced
WHAT DO YOU THINK HAPPENS WHEN A WAVE REACHES A BOUNDARY?
What happens when a wave hits something? ·Reflection: bounce off and goes in a new direction. ·Refraction: bends as it crosses the edge http://www.echalk.co.uk/Science/Physics/rippleTank/ripple.htm
·Diffraction: bends as it goes around a corner or through an opening ·Absorption: amplitude gets smaller and smaller as it passes through the material http://www.echalk.co.uk/Science/Physics/rippleTank/ripple.htm
WHAT DO YOU THINK HAPPENS WHEN TWO WAVES MEET EACH OTHER?
What's the relationship between frequency and wavelength? Copyright (c) The University of Colorado, under the GNU General Public License (GPL)
Students should base their responses on observations from the simulation. They record their answers here. Pul l How would you define frequency? How would you describe the relationship between frequency and wavelength?
Wavelength Transverse = distance from crest to crest Longitudinal = distance from one compression to another Frequency Number of complete waves that pass a given point in a certain amount of time. Units (Hz) or waves/sec
Amplitude for transverse wave The distance from the rest position to a crest or to a trough. Amplitude of longitudinal waves How compressed or rarefied the medium becomes...
Frequency, amplitude, and wavelength parts to a wave ·Frequency of a wave is a measure of how often it goes up and down and is measured in hertz (Hz) ·Amplitude of a wave is the height of the wave above the level surface ·Wavelength is the length of one complete cycle of a wave. Typically measured from crest to crest or trough to trough
Speed ·Speed describes how fast the wave moves ·Speed is frequency (f) times wavelength (l) Speed (m/sec) Frequency (hz) Wavelength (m) erase to reveal
Wave Calculation Worksheet c lick for worksheet Using the Equation 1.How fast does a 500 Hz wave travel if its wavelength is 0.5m? v=? f=500Hz v λ f λ=0.5m v=(500hz)(0.5m) v=250m
Speed The speed, wavelength, and frequency of a wave are related to each other by a mathematical equation. Speed = Wavelength x Frequency or Frequency = Wavelength =
Practice problems The frequency of a wave is 5/s or 5Hz. The wavelength is 10cm. What is the speed of the wave? Hint: Speed = Wavelength x Frequency The speed of a wave on a rope is 75cm/s and its wavelength is 5cm. What is the frequency?
More problems Wavelength = 5mm, frequency = 2Hz. At what speed does the wave travel? The speed of a wave on a guitar string is 100m/s and the frequency is 1,000Hz. What is the wavelength of the wave?
There are three types of waves: 1) __________ 2) ________ 3) _________ The properties which are common to all waves are 1) ________ 2) _________ 3) _______ 4) __________
Volcano The loudest natural sounds ever made on earth are considered to be gigantic volcanic eruptions. One such example is the explosions at the island of Krakatoa.
Whale Sperm whale uses sound to stun or kill its prey. It's grunts are immensely powerful bursts of sound which can disable nearby fish, squid and other victims.