Superposition and standing waves we are what we believe we are. These notes are combined with chapter 14 oscillations. We strongly recommend that at least the basic concepts discussed in this section are familiar to you before attempting further experimentation. Mechanical waves sound waves, waves on water are a. As the wave moves, compressions and rarefactions are produced due to the back and forth motion of particles of the medium. This note explains the physics of waves and oscillations including sound, elastic and electromagnetic waves. Speed of sound waves depends upon the properties of the medium.
The ear mechanism is able to respond to both very small and very large pressure waves by virtue of being nonlinear. Jun 23, 2019 we begin our study of waves in this first unit of physics 7c with an introduction to waves and then a thorough development of the harmonic plane wave model, which we will use extensively to model and understand a wide variety of wave phenomena. In the most general sense, sound is the propagation of density waves through some medium. E youngs modulus for a solid material, or the bulk modulus for a fluid. Longitudinal waves well, the best example would be sound waves, but you saw them on springs as well. Sound waves are longitudinal waves that must pass through a medium, such as air. Because of the enormous nonlinearity of the ear in sensing pressure waves, a nonlinear scale is convenient in describing the. Sound wave, a longitudinal wave, is discussed in this lecture. Speed of sound in air about 340 msec varies strongly with temperature. Whether youre talking out loud or texting on your phone, theres going to be a wave transmitting information. This vibrations set particles in the sur rounding medium typical air in vibrational motion, thus. It includes descriptions of sound wave characteristics like. Based on the wave theory, poisson, aragoand fresnel predicted that there should be a. Concepts of sound wave physics acoustics while demonstrating.
In this section we will familiarize ourselves with waves by concentrating on material waves. Reflections of sound waves also obey the laws of reflection. We hear so many sounds in our surroundings in our daily life. The physics of waves version date february 15, 2015. Electromagnetic waves are dealt with more fully in another section of this book. The physics classroom teacher toolkits sound waves sound waves pdf version the pdf version of the teacher toolkit on the topic of the nature of sound is displayed below. The animal emits a pulse of sound a longitudinal wave which, after reflection from objects, returns and is detected by the animal. The nature of waves summary the physics hypertextbook. Speed of sound is generally greater in liquids than gases and typically fastest in solids. Their vibrations occur in the same direction as the direction of travel.
The wave equation outline of mechanical waves longitudinal and transverse waves waves in a string, sound waves the wave equation description of waves using functions of two variables travelling waves the wave equation 0 y v y 1 2 2 2 2 2. The term sonic is applied to ultrasound waves of very high amplitudes. The fourth section uses the ideal string model to derive the onedimensional homogeneous wave equation. May 02, 2015 this video explains how sound waves work and how speakers work to reproduce sound. With that said, the approach here will be to understand music and musical instruments first, and to study the physics of waves and sound as needed to push the understanding of the music concepts. Swanson will have shown you a lovely demonstration of these two types of waves. How can it make sense to use the same word wave for all these disparate phenomena. Ultrasound images are created by reflected sound waves returning back to the transducer. This explains why you almost always see the flash of lightning before hearing the crash of the thunder. Pdf sound waves are the most common examples of longitudinal waves. Sound lies at the very center of speech communication. The part of a longitudinal wave, where particles of the medium are compressed together, are called compressions. Sound is caused by vibrations, of the front of a violin or a cello, or of the column of air inside a trumpet.
Benjamin cardozo we would accomplish many more things if we did not think of them as impossible c. Physics 1101 introduction to sound waves instructor. Traveling waves appear only after a thorough exploration of onedimensional standing waves. Does the wind affect the pitch of the factory whistle you hear of a windy day. Sound is a pressure wave which is created by a vibrating object. Physics of sound penn state mechanical engineering.
Sound waves consist of areas of high and low pressure called compressions and rarefactions, respectively. Because of the central role played by sound in speech communication, it is important to have a good. The medium most commonly encountered by most human beings is air, but sound also travels through water, rubber, steel, and tofu. A region of decreased pressure on a sound wave is called a rarefaction. Topics include beats, amplitude modulation, and frequency modulation. Lecture 11 chapter 16 waves i university of virginia. Pdf waves, light waves, sound waves and ultrasound the. Transverse waves water waves, waves on a string or spring, seismic waves, and electromagnetic waves. The unit is the mks rayl newtoncubic meter u p z 5. Materials on this site may not be updated for the current. Class 11 physics revision notes for chapter 15 waves free pdf download. Periodic waves are reflected and inverted and interfere with one another creating standing waves. Density of the medium stiffness of the medium atomic springs solids and liquids are more rigid than gases so sound waves move faster. Vibrations in air are called traveling longitudinal waves, which we can hear.
Holt physics 2 section quizzes assessment sound section quiz. Apr 15, 2020 on the atomic scale, sound is a disturbance of atoms that is far more ordered than their thermal motions. Speed of sound is generally greater in liquids than gases and. Sound waves and light waves carry energy that enable you to hear and see the world around you.
Lee calculates the speed of sound using two extreme cases. It works equally well for waves on a string, sound waves, and electromagnetic waves. The wave equation outline of mechanical waves longitudinal and transverse waves waves in a string, sound waves the wave equation description of waves using functions of two variables travelling waves the wave equation 0 y v y 1. Sound from a vibrating body produces longitudinal waves. Sound a disturbance which propagates through an elastic material at a speed which is characteristic of that material. How sound works the physics of sound waves youtube. For example, it can be used to show that electromagnetic waves move at the speed of light. Sound waves write the letter of the correct answer in the space provided. Impressively broad in scope, physics of waves offers a novel approach to the study of classical wave theory a wideranging but thorough survey of an important discipline that pervades much of contemporary physics. A longitudinal wave can be created in a coiled spring by squeezing several of the turns together to form a compression and then releasing them, allowing the compression to travel the length of the spring. If a sound wave hits your ear and makes it vibrate, you hear the sound. All other selfstudy revision notes are also available for download, free of charge. Despite this, some understanding of the basic physics used in ultrasound is needed for optimal creation and interpretation of an ultrasound image.
Motion of the waves energy motion of individual molecules of the wave transverse waves two motions are perpendicular waves on a string, water surface waves longitudinal waves two motions are parallel sound waves waves can have both transverse and longitudinal motion. Longitudinal waves, such as sound waves, move parallel to its source. Pdf ap physics 1 practice workbook book 1 mechanics. Write a short paragraph describing water waves you have seen.
I hope to emphasize that the physics of standing waves is the same. Repeated motion sends out periodic sound waves p p. The speed of sound in air generally increases by 0. The wave in which the particle experiences displacement parallel to the direction of the propagation. Along with the transverse and the longitudinal waves some waves in nature demonstrate the combination of both such as water wave. The angle of incidence is equal to the angle of reflection at point of incidence. Sound, like all waves, travels at a certain speed and has the properties of frequency and wavelength. Plane waves propagation direction w plane waves have a propagation direction and therefore plane wavefronts e. Ap physics 1 practice workbook book 1 mechanics, waves and sound, electrostatics and dc circuits. Wave motion and sound pdf 11p currently this section contains no detailed description for the page, will update this page soon.
Part 2 wave motion and sound the general discussion of wave motion is important because the ideas of wave propagation are ubiquitous. The result of longitudinal waves is the creation of compressions and rarefactions within the air. Sound from an instrument to ear cell phone to cell tower and vice versa em waves water waves a disturbance in the water moves outward. In fact, most homogeneous substances conduct sound. Newton rejected the wave theory for good reason, but assumed the waves would be longitudinal like sound. The speed of sound depends upon the type of medium and its state. If playback doesnt begin shortly, try restarting your device. The physics classroom grants teachers and other users the right to print this pdf document and to download this pdf document for private use. The part of a longitudinal wave, where particles of the medium are spread out, are called rarefactions. Sound propagates through air or other mediums as a longitudinal wave, in which the mechanical vibration constituting the wave occurs along the direction of propagation of the wave. In the case of sound waves, the vibrations create a series of compressions and expansions and the wave travels along the compression in the direction of the propagation. In nearly all areas of science and therefore real life energy is transferred via the vibrations that make up waves. Waves are responsible for basically every form of communication we use. Waves and sound 2006 question 8 ordinary level i describe, using diagrams, the difference between transverse waves and longitudinal waves.
The incident sound, the reflected sound and the normal lie on the same plane. Echolocation waves can have frequencies of about 100,000 hz. He also measures the speed of sound using an inclass demo. A sound wave is an air pressure disturbance that results from vibration. Physics 1101 introduction to sound waves instructor sings, and then plays various instruments instructor oh, this unit is going to be so much fun. A water wave is an example of a surface wave, which is a combination of transverse and longitudinal wave motions. A sound wave is both the end product of the speech production mechanism and the primary source of raw material used by the listener to recover the speakers message. Electromagnetic waves include, radio waves, microwaves, infrared, light, ultraviolet, xrays, and gamma rays. There is energy transport the disturbance propagates, but there is no net transfer of mass no. The simplicity, breadth, and brevity of the book make it ideal as a classroom text or as a vehicle for selfstudy. A region of increased pressure on a sound wave is called a compression or condensation. Class 11 physics revision notes for chapter 15 waves.
How does the vibration frequency relate to the frequency of the wave created. A wave is a disturbance that propagates through space. You can observe direct evidence of the speed of sound while watching a fireworks display. Sound waves can be reflected by hard, flat surfaces, and absorbed by soft ones. Aipmt neet physics waves and sound mcq practice sample papers problems free pdf download with solution 2017 2018. Hypersound, sometimes called praetersound or microsound, is sound waves of frequencies. The vibration can come from a tuning fork, a guitar string, the column of air in an organ pipe. At such high frequencies it is very difficult for a sound wave to. Any disturbance that complies with the wave equation can propagate as a wave moving along the xaxis with a wave speed v. Hypersound, sometimes called praetersound or microsound, is sound waves of frequencies greater than 10 hertz. Malesherbez the only limit to our realization of tomorrow will be our doubts of today.
Sound waves are longitudinal waves that must pass through a medium. Longitudinal waves two different motions to describe in a wave. Thus, sound waves can induce oscillations and resonance effects figure \\pageindex2\. Sound waves pdf version the pdf version of the teacher toolkit on the topic of the nature of sound is displayed below. Examples of wave motion include waves on strings, water waves, seismic waves. There are familiar, everyday sorts of waves in water, ropes and springs. Sound waves, intensity level, decibels, beat frequency. A transverse wave is made up of a series of positive pulse and negative pulses. In many instances, sound is a periodic wave, and the atoms undergo simple harmonic motion. Ultrasonics, vibrations of frequencies greater than the upper limit of the audible range for humansthat is, greater than about 20 kilohertz.
Sound is caused by vibrations, of the front of a violin. The vibrating body causes the medium water, air, etc. Lessons lecture notes the physics classroom conceptual waves. The goal however is a deeper understanding of the physics of waves and sound than. Pressure and displacement of sound waves in tubes khan academy. Attention is given to both the purely conceptual aspect of sound waves and to the mathematical treatment of the same topic. The physics classroom grants teachers and other users the right to print this pdf document and to download this pdf document. Properties of sound waves sound waves travel at about 340 ms in the air much slower than the speed of light. Sound waves revision notes learn igcse physics oxnotes. Sound can travel through any medium, but it cannot travel through a vacuum. So lets start by finding out what all these sounds, from the pleasing ones to.
Even more important, though only touched on in this book, is the wave phenomenon of quantum mechanics, built into the fabric of our space and time. Introduction to the physics of waves and sound uvic. To study the properties of common waves waves on strings, sound waves, and light waves. In the case of sound waves, the vibrations create a series of compressions and expansions and the wave travels along the compression in. Speed of sound waves two factors affect the speed of sound waves. A century later it was postulated that light could be a transverse wave. Nov 28, 2016 this physics video tutorial explains the concept of sound waves and how shows you how to calculate the wavelength, frequency, and velocity of sound waves. Bending waves in a beam or plate, and water waves are a mixture of shear and longitudinal waves. Physics of sound, and an introduction to the apparatus.
The alternating configuration of c and r of particles is described by the graph of a sine wave ccrests, rtroughs the speed of a sound pressure wave in air is 331. There are less visible but equally pervasive sound waves and electromagnetic waves. Have you ever thought about what actually produces the sound. This physics tutorial discusses the nature of sound, its characteristic behaviors, and its association with the operation of musical instruments.