Goal for this unit:

1. 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.

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

3. 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?

4. Nature of Waves energy matter • 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 • http://www.youtube.com/watch?v=8i6hTU0jw-g space vibrating particles solid, liquid, or gas

5. Waves that do NOT need a medium are called _________ __________ ___ Examples: _______ ______ Microwaves x-rays T.V. & radio waves Waves that need a medium to move are called _________ ______________Examples: _____________ _____________ Seismic waves (earthquakes) Nature of Waves electromagnetic waves mechanical waves Sound waves Visible light Ocean waves http://www.youtube.com/watch?v=7yPTa8qi5X8 ocean wave animation

6. Types of waves energy • All waves transfer ________ by repeated _______________. • _______________waves—particles vibrate in an ________________motion while the energy moves across. vibrations Transverse up-and-down Particles Energy http://www.youtube.com/watch?v=TZIr9mpERbU&NR=1 rope example http://www.youtube.com/watch?v=g49mahYeNgc slow motion

7. Longitudinal • ___________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 Compression Particles & Energy

8. Wave animations • http://www.youtube.com/watch?v=7cDAYFTXq3E • http://www.youtube.com/watch?v=JsJOug4SqL8

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

10. Wavelength—thedistance 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

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

12. Wave property animations • Wave motion: change frequency, wavelength etc…http://profhorn.aos.wisc.edu/wxwise/kinematics/wavemotion.html • Characteristics of Waves: Amplitude, Wavelength and Frequency http://www.youtube.com/watch?v=aif5mxf5DtU

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

14. Refraction bending • _________—the ________ of light waves as they pass through from one medium to another at an angle. • 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

15. Diffraction • _________—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 _____________________. another object to vibrate http://www.acoustics.salford.ac.uk/schools/teacher/lesson3/flash/whiteboardcomplete.swf interactive wave disturbance tutorial

16. 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. • http://www.youtube.com/watch?v=CsKKDLKYsVU • http://www.wsdot.wa.gov/tnbhistory/connections/connections3.htm

17. Label the wave parts 1 second 0 seconds Type of wave: Longitudinal Frequency: ____ Hertz 3 wavelength __________ amplitude Type of wave: Transverse Frequency: ____ Hertz __________ 3.5 wavelength ___________

18. Waves Transverse Longitudinal Energy Medium Frequency Amplitude Wave speed http://sci-culture.com/advancedpoll/GCSE/sine%20wave%20simulator.html wave simulator