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  • 1. Wave Interactions

2. Waves All Around Us Imagine you just spent a day at the beachwith your family. You had a blast playing in theocean, laying out in the sun, listening to musicand talking with your family. When you goback to the condo, you heat up some pizza inthe microwave and turn on the TV. Can you name all the different waves thatwere present in your day on the beach? 3. Standard S8P4. Students will explore the wavenature of sound and electromagneticradiation. B. Describe how the behavior of lightwaves is manipulated causing reflection,diffraction, refraction, and absorption. 4. Review From the list of waves you just named, canyou identify whether it is electromagnetic ormechanical? What is the difference betweenelectromagnetic waves and mechanicalwaves? Which one needs a medium? What is a medium? Name 3. Which one causes vibrations? 5. Reflection Waves bounce back All waves can be reflected We can see objects because of the visiblelight waves that are bounced off of them Waves bounces back at the same angleas it hits the object Angle of incidence(original wave) Angle of reflection(bounce back) 6. Scattering Scattering A type of reflection Waves collide with matter and reflect in manydifferent directions Blue sky shortest wave length of visible lightscattered by particlesin the atmosphere 7. Refraction Wave bends as it is transmitted Due to different wave speeds in differentmediums gas to solid, gas to liquid Causes optical illusions 8. Refraction Rainbow When white light waves separate by refraction, we see colors 9. Diffraction Most times waves travel ina straight line Can bend around a barrier Edges of the object are blurry Example eclipse, x-ray Can bend through an opening Sound waves are much longerthan light waves Sound waves bend more 10. Absorption Absorption Transfer of energy to an object light to heat light to chemical (by plants with photosynthesis) light to battery to electrical (by solar panels) Soaks up waves Makes waves dimmer loss of energy 11. Interference Overlapping waves Share space Either increases amplitude constructive The thump from the car stereo next to yours. Or, decreases amplitude destructive You may not hear the person sitting two seatsaway from you when the cafeteria is crowded. 12. Constructive interference happens when waves add up to make alarger amplitude. Suppose you make two wave pulses on astretched string. One comes from the left and the othercomes from the right. When the waves meet, they combine tomake a single large pulse. 13. Destructive interference What happens when one pulse is on topof the string and the other is on thebottom? When the pulses meet in the middle, theycancel each other out. During destructive interference, wavesadd up to make a wave with smaller orzero amplitude.