Goal for this unit:  Explain that earthquakes, light and sound are all types of waves with unique properties and that there are differences and similarities between electromagnetic and mechanical waves.  Pre-knowledge Level: ?/33  Please write three actions you plan to do to be successful in this unit: Ask for help when needed, review notes and handouts on a regular basis, focus in class.

The Energy of Waves Learning Goals: 1. Describe how waves transfer energy. 2. Describe the difference between transverse & longitudinal waves. 3. Describe the properties of amplitude, wavelength, and frequency. 4. Compare the properties of waves to the wavelike property of energy in earthquakes, light, and sound. 5. Describe how waves interact through reflection, refraction, diffraction.

Essential questions  What is a wave?  What is a medium?  What is the difference between a longitudinal and transverse wave?  What are the properties of a wave?  What behaviors do all waves have in common?  What is the difference between reflection, refraction, and diffraction?

Nature of Waves  Wave—any disturbance (movement) that transfers _______through _______ or empty ________.  Waves move energy by ____________ __________in a medium.  Medium—a substance a wave can travel through; it can be__________________.  Characteristics of Waves: Sound waves  energymatter space vibrating particles solid, liquid, or gas

Nature of Waves  Waves that do NOT need a medium are called _________  __________ ___  Examples: 1. _______ ______ 2. Microwaves 3. x-rays 4. T.V. & radio waves  Waves that need a medium to move are called _________ ______________Ex amples: 1. _____________ 2. _____________ 3. Seismic waves (earthquakes) electromagnetic waves Visible light mechanical waves Sound waves Ocean waves ocean wave animation

Types of waves  All waves transfer ________ by repeated _______________.  _______________waves—particles vibrate in an ________________motion while the energy moves across. Particles Energy energy vibrations Transverse up-and-down rope example slow motion

 ___________ wave—the particles of the medium vibrate back and forth in the same direction the wave energy is moving.  ____________ —part of a longitudinal wave where the particles are crowded (pressed) together Particles & Energy Longitudinal Compression

Wave animations  TXq3E TXq3E TXq3E  4SqL8 4SqL8 4SqL8

Properties of waves   Amplitude—(wave height) distance from the rest position to the crest or trough   Large amplitude=more energy crest trough rest position

Wavelength —the distance from any point on a wave to an identical point on the next wave. (crest to crest, trough to trough, compression to compression, rarefaction to rarefaction) Shorter wavelength=more energy

 Frequency —the number of _________ passing through an area in one _______, measured in _______ (Hz) Low frequency-few waves Per second Higher frequency—more Waves per second 1 second waves second Hertz 1 Hertz = 1 wave per second 5 waves in 1 second= 5 Hz 5 waves in 1 second= 5 Hz Higher frequency= higher energy Wave speed— speed at which a wave travels =frequency x wavelength

Wave property animations  Wave motion: change frequency, wavelength etc… http ://profhorn.aos.wisc.edu/wxwise/kinematics/wavemotion.h tml http ://profhorn.aos.wisc.edu/wxwise/kinematics/wavemotion.h tml http ://profhorn.aos.wisc.edu/wxwise/kinematics/wavemotion.h tml  Characteristics of Waves: Amplitude, Wavelength and Frequency

Wave Interactions  ___________—when a wave _______ __ _ _ _____after hitting a barrier it can’t go through. Reflection bounces back echo All types of waves can be reflected Example: ______ —a reflected sound wave, sonar Light waves reflected off an object allow you to see it. surface

 _________—the ________ of light waves as they pass through from one medium to another at an angle. Refractionbending  When a wave passes from one medium to another, it’s speed and wavelength changes so it _________. Examples: White light bends to form a rainbow bends

 _________—the change in direction of a wave as it bends around a barrier or opening  Resonance —when two objects vibrate at the same frequency; one object causes _____________________. Diffraction another object to vibrate c.uk/schools/teacher/lesson3/f lash/whiteboardcomplete.swf c.uk/schools/teacher/lesson3/f lash/whiteboardcomplete.swf interactive wave disturbance tutorial

 A resonating object absorbs energy from the vibrating object and begins to vibrate too. The 4 month old bridge collapsed during a windstorm with gusts that reached 68 km/h (42 mph). The catastrophe was attributed to faulty design. Instead of allowing the wind to pass through, the suspended girders caught the wind, causing the bridge to buck and roll. The bucking motion earned the bridge the nickname Galloping Gertie. The stronger the wind blew, the more violently the structure oscillated, until it finally broke apart and crashed into the water

Label the wave parts Type of wave: Longitudinal Frequency: ____ Hertz Type of wave: Transverse Frequency: ____ Hertz amplitude wavelength 0 seconds 1 second __________ ___________

Waves Transverse Longitudinal Frequency Wave speed Amplitude Energy Medium wave simulator