This is a demonstration of what wave phenomenon… Resonance Can sound waves travel in a vacuum? NO, they need a medium to travel through. The distance between one waves crest and the next waves crest is called a ___________. wavelength For each second you count between lightning and the thunder it produces, how far away does it mean the lightning is from you? 340 meters About 1/5th of a mile Or about 1/3rd of a kilometer Noise cancelling headphones are an example of ________ interference. Destructive What causes a tsunami? An underwater earthquake OR a massive landslide If an ambulance is headed toward you the frequency of the sound waves coming toward you is ________ than normal. Higher frequency Shorter wavelength The frequency of the sound coming from that same ambulance would be ________ than normal as it moves a way from you Lower frequency Higher wavelength A wave travels a distance of 20 meters in a time of 4 seconds, what is the speed of the wave? 5 m/s Which of these would sound travel the fastest through Salt water Fresh water A wood cabinet A steel beam Steel beam, because it is the most rigid Is there sound in outer space? NO, space is a vacuum and sound needs a medium to travel through On a standing wave, the points that do not move are referred to as….. Nodes The number of times a wave vibrates each second is referred to as _______ frequency The amount of time it takes each wave to pass is referred to as _______ Period What type of wave is a sound wave? Longitudinal wave Waves in the ocean are what type of wave Transverse What is the proper unit for frequency? Hertz An oceanic depth-sounding vessel surveys the ocean bottom with ultrasonic sound that travels 1530 m/s in seawater, and finds a 10-second time delay of the echo to the ocean floor and back. The ocean depth there is 7650 meters Beats are produced by two tuning forks that are sounded together, if one tuning fork has a frequency of 300 Hz and the other has a frequency of 305 Hz, what will be the frequency of the beats they produce? 5 Hz Difference between frequencies What destroyed the Tacoma Narrows bridge? Resonance/ Standing Wave A standing wave was created when the bridge resonated at its natural frequency as caused by the wind. A 680 Hz sound wave that travels through air at a speed of 340 m/s would have a wavelength of____? .5 meters V = fλ So λ = v/ f or 340 / 680 12 full waves pass a dock in a time of 6 seconds. A) what is the frequency of the waves? B) What is the period of the waves A) 2 Hz B) .5 seconds A skipper on a boat notices wave crests passing the anchor chain every 6 seconds. The skipper estimates the distance between crests at 30 m. What is the speed of the water waves? In what kind of situation(s) would the doppler effect occur? If a source of sound waves is moving toward you or away from you If the frequency of a set of waves is increased, what will happen to wavelength? It will go down Inverse relationship What of these wave properties determines the pitch of a sound wave? Frequency Wavelength Period Speed Frequency High frequency high pitch What is the source of all wave motion? Vibration A wave created by shaking a rope up and down is called a ______ wave. Transverse A wave has a wavelength of 1.5 meters. During a single period this wave has travelled how far? 1.5 meters The amplitude of a wave is 3.0 meters, the top to bottom distance of the disturbance would be 6 meters What property of a wave determines loudness? Amplitude Two waves that are in-phase with each other will undergo _______ interference. Constructive New larger wave will be produced Amplitudes add together The phenomenon of ‘beats’ results from which of these Interference Diffraction Frequency modulation resonance interference T or F. We would hear a sonic boom the instant a supersonic plane flew overhead. False, it would be after the plane was directly overhead because the planes sound is trailing it T or F. Resonance occurs when an object vibrates at its natural frequency True Every elastic object has its own natural frequency, when it vibrates at that frequency a large increase in amplitude will happen A certain ocean wave has a frequency of 10 hertz and a wavelength of 3 meters. What is the wave’s speed? 30 m/s The period of a wave is 8 seconds, what is its frequency? 1/8 Hz How do we use the Doppler Effect to tell us that the universe is still expanding? All galaxies are ‘red-shifted’ meaning they have longer wavelengths of light, this tells us they are all moving away from us…. Universe is expanding If you have created a standing wave with a slinky and increase the frequency with which you are shaking the slinky what will happen to the number of waves in the slinky? Number of waves will increase Wavelength of each wave will decrease more waves crammed into the same length The regions in between the compressed regions of a sound wave are called _________. Rarefactions The amplitude of a water wave is .5 meters. If a raft has one full wave pass under it… through how much distance will it vibrate? 2 meters 4 amplitudes How is a sonic boom formed? Something moving faster than the speed of sound What other than a jet-powered vehicle can create a sonic boom? Crack of a whip What does ‘ultrasonic’ mean? Sound waves that have a frequency higher than that which is audible >20,000 Hz.