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waves, sound, and electromagnetism

Added Feb 22, 2019 •

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the ocean pounding on the shore The Sound of Music light emanating from the Sun and the transmission of a television program what do these things have in common they are all examples of energy being propagated by waves although we cannot see many time wait nonetheless they play a very important role in our physical world we're going to look at the common characteristics and major differences of various waves and show how they are essential to the city of energy on Earth and through the universe the waves are crashing into this rock Atlanta were caused by the wind pushing against the water surface as each wave Moves In from offshore it is transporting the energy of that disturbance this movement of energy is seen clearly when a stone is dropped into a pool of water what happens is that the energy of the falling Stone makes a disturbance in the water and that disturbance creates the wave as a wave radiate outwards the water ride and then Falls eventually returning to equilibrium what moves out words with the wave is not the water it is the energy of the disturbance the energy is transported by two basic types of transverse and longitudinal and a transverse wave the disturbance is perpendicular to the direction of travel while in a longitudinal wave the disturbance is parallel to its direction of travel but all waves have some common characteristics the wavelength is the distance of one complete wave this wave is measured from Crest to Crest but it could be measured from any other frequency is the number of wave Cycles in a given unit of time it is usually measured as the number of waves per second and expressed as a Hertz HZ amplitude is a maximum difference of the disturbance sometimes it is called the height of the wave velocity or the speed of the wave is the relationship between the waves and the frequency it is found by multiplying the two together the velocity of the wave is limited by the properties of the medium through which it travels wavelength frequency amplitude and velocity are common to all waves but all waves are traveling disturbances that carry energy from place to place sound is a transfer of energy caused by any vibrating material and is transmitted by longitudinal waves sometimes they're called compression waves this Slinky toy it works as it is pushed out some rings of the slinky Bunch up and others are spread out if we can see the longitudinal waves of sound this is what they would look like sound wave is created the wave of energy moves outward from the source pushing the air molecules back and forth parallel to the direction of the wave motion the molecules next to the source of the sound are forced outward head bump into other molecules passing the sound vibrations on to them and so the energy of the vibrations radiates outward when the wave arrives at the audience the molecules vibrate the individual's eardrums and The Listener interprets the vibrations as sound the sound waves have carried the energy of the music through the media of the are a medium can be are water for any solid material it is essential for the transmission of sound because there must be molecule's to vibrate and transfer the energy we can't see the sound waves in the air but it can be easily demonstrated that sound creates waves this tuning fork is vibrating at 440 cycles per second when tipped into the water a disturbance launch by the vibrations is clearly visible the waves of energy have been transferred to the water perception of sound is shaped by the nature of the wave would allow musical note is created the amplitude or height of the wave is greater the louder than always the higher the wave the waves of this high pitch Note have a high frequency this means that it is producing far more waves per second Dennis low pitch note the higher the pitch the greater the frequency of waves the human ear can hear a broad range of sounds from 20 Hertz to about 20,000 Hertz in other words we can hear frequencies from 20 Waves per second to about 20,000 Waves per second other animals can hear a much wider range of sound dogs for example can hear sounds up to 40000 Hertz and that up to 100,000 Hertz the speed of sound is dependent on them the travel through but if there is no medium there can be no sound there is no there are no to move the energy of the sound vibrations social space is soundless so then how do astronauts hear their space council's and space suits hold are so they can breathe and hear sound always needs a medium to travel speed vary somewhat depending on the temperature at room temperature the speed through the air is 343 m per second or 1125 ft per second at freezing point soundtrack 332 meters per second or 1089 ft per second but sound travels much faster in both liquids and solids in the ocean 1525 meters per second or 5000 feet per second and in solids much faster is still in Earth sound travels at 3350 meters per second or 11,000 feet per second the question is why are there these differences in the speed of sound the molecules in water are much closer together than air and install material They are packed even closer in a dense medium the sound vibrations do not have as far to travel this is called the elasticity of the medium the more elastic the medium the faster the sound waves will travel seismic waves from explosions an earthquake's send a very intense longitudinal waves with huge amplitude the same as sound wave but they also transfer energy through transfer switch disturbances of energy can travel up to seven times faster than the speed of sound in air the waves can be of such magnitude that he'll size blow-up and buildings collapse has long been a fascination of scientist but it travels so fast that it was very difficult to study Isaac Newton the brilliant English physicist who lived in the 17th century believed that light was made up of extremely small articles but he could not explain how it traveled others believe that light was energy that travels in waves but they could not figure out how light waves could travel through space by that time quite a lot was knowing what sound and it was felt that all energy needed a medium in which to travel scientist concluded that space had to be filled with some type of matter they called ether which acted as the medium for like any 73 James Clerk Maxwell a British physicist result most of these problems Maxwell developed equations based on the earlier work of Michael Faraday who had demonstrated the link between electric field and magnetic fields the oscillations or movements back and forth of electric charges generate electromagnetic waves of energy which propagate as transverse waves Maxwell's calculations of the velocity of these waves match the speed of light and let him to predict that light is an electromagnetic wave since electric and magnetic fields can cyst in both a material substance and a vacuum these waves do not require a medium and can travel through air water or the vacuum of space once that was understood this is abandon the notion of ether if we could see them transverse waves would look something like the waves in this rope or the ripples on the surface of a pond this animation of an electromagnetic wave shows both you Optical and magnetic component of the way note the two parts of the waves are at right angles to each other Maxwell believed the electromagnetic waves are only energy but it is now known that they are both waves of energy and particles called photons this is called the wave particle duality electromagnetic waves travel through space at the speed of light our greatest source of electromagnetic waves is the Sun but it is also the energy and radio and television waves electric bites the light emitted from fire the atoms that the matter and much more electromagnetic waves are everywhere in our universe all waves can be distorted deflected or changed when they come in contact with a boundary it is comparatively easy to see these effects with both water waves and sound waves but even electromagnetic waves are in lunch by distortions reflected waves change Direction when they bounce off a barrier we have all heard sound Echoes and understand that it occurs when sound waves are reflected off a building or a cliff face when sound travels through a medium like air and Strikes another medium like this canyonwall some of the sound for reflect back to us as an echo sonar uses the same by transmitting sound waves through the water and timing The Echoes that come back in order to create an image of the ocean floor Dolphins use sonar echolocation to hunt for food reflection also works for other types of waves these waves of water are being reflected off the rocks mirrors reflect light and you're able to see because of the reflection electromagnetic waves when light reflects off objects those objects become visible to our eyes this pencil appears to be broken at the waterline this is due to refraction Electronics attic waves travel faster in air than they do in water and as a result when they go from one medium to another the image appears bent because the light-ray deviates from its normal Direction refraction is the bay just of lens technology it also occurs with sound waves and all other waves diffraction is a term used when waves spread out around the edges of objects this is why we can hear a row corners light waves can also be diffracted and this phenomenon was put to use in the lens technology for beacons in lighthouses wow that car horn had a high-pitch as it approached and a lower pitch as a car retreated down the street that is called the Doppler effect if the car was standing still the sound waves would travel at the same speed and the sound of the horn would have a constant pitch but as a car comes towards us each successive sound wave travels a shorter distance to reach our ears the waves arrive at a more frequently and that's have a higher pitch as the car travels away from us each successive wave travels a longer distance to reach our ears and produces a lower pitch light rays also exhibit the Doppler effect in the 1920s and American astronomer Edwin Hubble observed at the colors of the stars in other galaxies were similar to those in our with one big exception the colors were all shifted a little towards the red end of the color spectrum Hubble realized that the reason for this is that the distance between other galaxies in our own play increased while the light from the stars have been traveling in other words the wavelength of the light had been stretched over a longer distance and therefore the way frequency had them just as it does for receding song Wyatt this discovery of the red shift is another example of the Doppler effect and is a reason astronomers and physicists have concluded that the universe is expanding the object like this one will vibrate and produce waves when it is Disturbed this is called its natural frequency when one tuning fork is run and brought close to another of the same frequency second Fork begins to vibrate in harmony with the first one it continues to ring even when the first part is removed this is called resonance and always results in an increase in amplitude when two waves meet while traveling in the same medium wave interference occurs if the displacement is in the same direction both up or both down it becomes constructive interference and the amplitude increases temporarily as they pass when sound waves are nearly the same they complement each other to produce a louder sound this often happens when musical instruments are played together destructive interference occurs when waves overlap and the displacements are in the opposite direction this can result either in silence or a softer sound then would be produced by the original waves a standing wave can rise when two waves overlap it occurs when waves of a denticle frequency traveling in opposite directions combined in that situation nodes are create where no movement of the medium occurs Play music This unique frequencies are called harmonics and overtones which make the sound more aesthetically pleasing Architects and Engineers apply the physics of sound in order to design buildings with good acoustics and musicians learn how the sound is created in there in so they can maximize its effect constructive and destructive interference can have an effect on always the most common interference in radio or television waves occurs when signals overlap usually what happens is the frequencies are too close and they interfere with each other the more physicists have learned about the nature of waves the more they have come to understand the function waves play in the universe waves transport the energy of disturbances true or false the number of wave Cycles in a given unit of time is called The Wave the speed of the wave is called its sound waves are play it's true or false longitudinal waves never need a medium to transport the energy true or false sound travels faster in are in the ground true or false visible light is transported by waves the Doppler effect only applies to sound waves or false Echoes of sound and mirror images are examples of refracted waves true or false all waves can be distorted reflected or changed true or false

Uploaded by Debra Hood.

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waves, sound, and electromagnetism

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