Name ____________________________________ Date _______________ Period _____ Notes Pages for PowerPoint Presentation – Waves Part 1: Kinds of Waves Slide 1: What is a Wave? A wave is a ____________________ in space/time that moves energy in a _____________________________ from one place to another. When waves move through matter, we call that matter the wave’s _________________. A medium can be a ____________, _________________, or a ______________. ___________________ waves can move through empty space and do not need any medium at all. When energy waves move through a medium, the medium is disturbed, but it stays in the __________________________ as the wave travels through it. In the ocean, when a wave passes, the water molecules only move in ________________ __________________! Slide 2: Types of Waves : Transverse A wave where the medium moves at _______________________________ to the direction of the wave is called a transverse wave. _______________ waves and ________________ waves are both transverse waves. (Copy and label picture in space below) Slide 3: Parts of a Transverse Wave The ______________ is the highest point of a transverse wave, and the _____________ is its lowest point. One wavelength includes one complete _______________ plus one complete_________________. 1 The _______________________ of a transverse wave is the distance from the normal to a _________________ or from the normal to a ______________________. The more energy a wave has, the greater its __________________________. (Copy and label picture in space below) Slide 4: Types of Waves: Longitudinal A ______________________ wave makes the medium move _____________________ to the direction in which the wave is traveling. ____________________ travels in longitudinal waves. Unlike some transverse waves that can travel through empty space, longitudinal waves ____________________ have a medium to travel through. This is why there is no sound in __________________________________. Slide 5: Parts of a Longitudinal Wave The part of a longitudinal wave where the particles of the medium are close together is a ___________________________. The part of a longitudinal wave where the particles of the medium are far apart is a ______________________________. One wavelength includes one complete ___________________ plus one complete ____________________________. (Copy and label picture in space below) 2 Part 2: Wave Properties (Characteristics) Slide 6: Wave Properties When you talk about a “big wave” at the beach, you are describing the wave’s ______________________________. If you describe how many waves pass you in a given time, you are describing the _________________________ of the waves. For transverse waves, the distance from crest to crest or trough to trough is a _________________________________. For a longitudinal wave, a ____________________________ is the distance between compressions or between rarefactions. It is measured in _____________________. (Copy and label pictures in space below) Transverse Wave Longitudinal Wave Slide 7: Wave Amplitude If you are looking at transverse waves (think ocean waves), amplitude is the __________ (up and down) distance from the normal to the crest or trough. As you increase a wave’s ___________________, its amplitude also increases. In other words, high energy waves have ____________ amplitude, and low energy waves have _____________ amplitude. (Copy and label pictures in space below) 3 Slide 8: Wave Frequency The _______________________ of a wave is the number of waves that pass by a place in a certain length of time. The most common unit for frequency is the _______________ (Hz), which means “__________________________________.” Notice that both waves below have the same amplitude, and therefore the same amount of _____________________. (Copy and label pictures in space below) Slide 9: Wave Speed Wave ______________________ measures how fast the wave is moving toward you. Wave speed = ____________________ x __________________________ The metric unit most often used to measure wave speed is ____________ per _________. In the open ocean, tsunami waves can travel at speeds of up to 550 miles per hour (890 km/hour)—as fast as a jet plane! Slide 10: Math Problems with Waves Wave Speed, Frequency, and are related by the formula: speed = frequency x wavelength This formula can be written in circle form and can be used to solve for any of the three values if the other two are known. Solve these. Show your work in KFCA form. 4 1) If a wave’s speed is m/s and its frequency is 650 Hz, what is its wavelength? K F C A 2) A wave traveling at a speed of 3500 m/s has a wavelength of 14 meters. What is its frequency? K F C A 3) A wave has a frequency of 250 Hz and a wavelength of 0.3 m. What is its speed? K F C A 4) A sound traveling at 340 m/s has a frequency of 8500 Hz. What is its wavelength? K F C A Part 3: Wave Interactions Slide 11: Wave Interactions: Energy and Change When a wave runs into another wave or into an object, the wave’s___________ changes. The change in the wave’s energy makes the wave’s ____________________ change too. Remember: wave properties include ____________, ____________________, ____________________, and ______________________. When an ocean wave hits the shore, its amplitude, speed, or wavelength might change. Wave interactions affect ____________ kinds of waves: ocean waves, light waves, and sound waves! Other changes that might happen are a change in the wave’s ____________________, or the wave might break apart and then re-form as a group of small waves. 5 Kinds of wave interactions include ____________________, _____________________, _________________________, and ________________________. Slide 12: Wave Interactions: Reflection ____________________ happens when a wave hits a surface and bounces off. The angle of the incoming (___________________) wave equals the angle of the outgoing (____________________) wave. This is called the _________________________________________. (Copy and label picture in space below) Slide 13: Wave Interactions: Refraction Waves change _________________ when they pass from one medium to another. Sounds travel fastest in _____________, slower in _____________, and slowest in a ____________ like air. Sound _________________ travel at all through a vacuum like space. Light travels fastest in a __________________ (outer space) slower through a ________, even slower through a ______________, and slowest through a ____________ like glass. ____________________ is the bending of a wave because it changes speed when it goes through different media. The green fish in the PowerPoint slide seems to be in a different place in the aquarium because the light waves bend when they change from water to air. 6 Slide 14: Wave Interactions: Diffraction The bending of a wave as it touches the edge of a barrier is called __________________. When waves are diffracted at the edge of a barrier, speed and direction may change, but wavelength and frequency might not change. ________________________ allows you to hear sounds around corners. ________________________ glasses split white light into rainbow colors. Slide 15: Wave Interactions: Interference The effect of two or more waves interacting with each other is called _____________________. There are two kinds of interference: ___________________ and __________________. When the crests and troughs of the interacting waves are in the same place at the same time, the result is a ________________ wave. This is __________________ interference. A tsunami is caused by constructive interference. (Copy and label picture of constructive interference in space below) When the crest of one wave meets the trough of another wave, the result is a smaller wave. This is _______________________ interference. In some seats of a poorly built auditorium, __________________ interference between sound waves makes it hard to hear what’s happening on stage. (Copy and label picture of destructive interference in space below) 7