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Waves Notes Part 1

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today we're going to start our conversation about weights first thing we have to ask ourselves is what is a wave waves are everywhere inside You observe many different kinds of waves everyday you see waves that move through matter such as those that can cause water to rise and sink in the ocean you feel ways such as those that produce heat and hear waves such as those that produce sound a wave is a regular pattern of motion created by vibratory disturbance a wave can move through matter some ways can move through a vacuum or empty space a wave transfers energy as it moves one place to another the thing about a wave though is even though it's moving energy doesn't move the matter and that's a big deal and you are asked about that so remember a wave transfers energy not matter so you can see energy carried by a wave traveling through matter to movement of waves actually the movement of energy through the matter in the picture dipping a finger and water is vibratory disturbance that travel through the water the movement of the way is actually the movement of energy most waves travel through a medium a medium is a substance gas liquid or solid through which a wave travels when a wave travels through a medium it causes particles in that substance to osculate auscultation is a rip and Regulatory vibration it is a back-and-forth motion across a point called equilibrium equilibrium is also known as the rest position so and auscultation is just going to be a back and forth back and forth back and forth so when a wave comes through it's going to go back and then go back to the resting position so I look here to osculation goes to the top down top down and then goes back to that beginning equilibrium rest position so it started there it ends there a jet of wave does not transfer matter it does transfer energy it does not transfer matter the wave causes articles to move down or left and right however they always return to equilibrium once it has mechanical waves are waves produced by Mukesh for a vibrating object mechanical waves require a medium they cannot travel through a vacuum another words that they can travel through space so mechanical need a medium m for mechanical and for medium chemical waves cannot go through empty space that can't go through that vacuum they are mechanical waves transfer energy through a series of collisions here's how an initial particle in the medium is to start the particle collides into another particle in a medium these particles than Collide into other particles the Collision continues to the transfer of energy through the medium and sound is an example of this sound is a mechanical way there are three main types of mechanical waves transverse waves 224 also called compression waves surface waves first let's talk about a transverse wave in a transverse wave the particles of the medium move perpendicular to the direction of the movement of the Waves so purple think about your t k a t is perpendicular to the line goes down the line goes across so here's an example of a perpendicular way notice that the mileage if I just followed that one black. All it's doing is going up and down so the movement of the. Is up and down but if you fall the wave the wave is going across to the wave goes across but the particles of matter go up and down making that tea making a perpendicular way transverse wave osculate and a vertical Direction okay so the particle movements going to be up and down I'd the medium goes up and down but the wave itself is going write in other words as a transverse wave moves from right to left the particles in the medium move up and down so examples when a person Disturbed a transverse wave moves through the waves move left or right while the particles of the wave move up and down to the way we move but the hope is just going up and down another type of wave is called a longitudinal wave another term for a longitudinal you make yours compression compression launch to know are the same thing so in a longitudinal wave the particle the medium in the same direction as the movement of the way they are lost their parallel to the movement of the way this looks like so what you she is the Wave Music crawl I noticed that you just watch one in the divisional particle it's moving across and back across and back just watch that one more time David and each individual particle goes across and back across and back now it is oscillating so it's going to go back and forth it's not just going to go keep going across so that is a longitudinal wave as a longitudinal wave moves across a medium particles osculate parallel to the direction of the way this produces areas where particles are compressed or spread out we call where they are compressed are close together a compression so you can see these ways a really really close together we compress them we brought them together where they're far apart is called a rarefaction pack a rare faction they're not very close compression very close together the easiest way to remember the difference between longitudinal and parallel parallel with the L they don't cross over launch to Pinellas it looks like a bunch of owls and they never touch the never crossover where is transverse with that he's going to be the crossover as the wave moves towards an area in the medium particles to life particles are pressed together in this area and that's they produce an area of compression we call this area a compression or insulation rarefaction it's where they're spread out compression is where they condense the come together example of a longitudinal white is our Slinky when a slinky is 2 * a longitudinal wave moves through it and spread out or refraction Arthur type of wave is a surface wave a surface life is a combination of a longitudinal and transverse way surface waves are called so because they travel on the surface of a medium such as land and water only particles on the surface of the medium light so here we can say a surface way notice that if you look at one particular particle of matter is oscillating is going back and forth and this time it's going in a circular motion is it going up and down hey which is perpendicular to the wave cuz the way it is moving across but it's also going parallel so it actually goes in a circle so it goes down around up down Circle that is a surface wave in a surface wave the particles Oscar like parallel and perpendicular to the motion of the way the combination these motions cause particles to move in a circular motion and that's what I just showed you that when we talk about waves there different properties we can talk to about and there are three main properties the amplitude the wave frequency amplitude is the height of the way pay how tall it is it's the maximum displacement of a wave from its rest position or equilibrium altitude is usually measured in meters so you can either measure it start at your resting Point your equilibrium right here you can either measure it from this point to the top which is called the crest the talk or you can start at the equilibrium and measure it to the trough the bottom because a trough and a Crest are opposite to one another now if you're going to make a mistake this is the mistake you'll make you measure from the top to the bottom trough that's doubling the amplitude you only want to measure either from equilibrium to the crest or equilibrium to the trough . amplitude for mechanical waves amplitude is related to the energy of the wave ways of the higher amplitude carry more energy for sale waves amplitude sounds too loud the higher the amplitude of a sound wave energy carried by the wave noise think about it takes a whole lot more energy to really loud if you are just missed but if you are yelling that takes a lot of energy so higher amplitude louder lower amplitude softer amplitude lower energy higher amplitude higher energy higher the mountain goes up more energy it's going to take for me get to the top of the lower the amplitude the lower that mountain is in the lower the energy it's going to take for me to get to the top of that mountain wavelength is the length of one Fleetway is represented with a Greek letter Lambda which I know it looks like a upside down y but that's what we call it wavelength is usually measured in meters this is not good I don't like how they met so cross that out I want you to measure wavelength either from one Crest to the next or from one truck to the neck because those are equal so it's either crest or trough to trough you never measure from Crest to trough that is not good it's either from Crest to Crest or trough to trough frequency is our third characteristics it is the number of times a wave Cycles through one second frequency is measured in hertz now when we start to talk about sound in the second part of this unit frequency is going to be a big deal now what I want to do is I want you to watch this video and it's very very important that you pay attention and listen because there is going to be a pop quiz at the end of this dear Tim and Moby are light waves sound waves ocean waves all the same thing is to the same basic thing transfer energy from one place to another but this is this divided waves into Two basic kinds mechanical and electromagnetic ocean waves seismic waves sound waves and Slinky waves are all mechanical waves because they need a medium to move through a medium is any kind of matter that is disturbed by energy that energy disperses through the media the form of waves which are basically chains vibrating molecules water waves move energy through the medium of water molecules sound waves can transfer energy through a medium of are liquid or solid molecules seismic waves travel through the ground usually after an earthquake Slinky waves move through the medium of individual Loops Slinkys a really useful for visualizing how much waves work you can think of each ring as an individual molecule when you shake one end of the toy you can see how that kinetic energy moves from one Slinky to the next move matter forward with the case just like with the slinky strings I feel Disturbed electromagnetic waves like light and radio waves don't need a medium to move through they can travel through completely empty space that's why I like waves from the sun and stars are able to reach Earth and why radio waves let us communicate with spacecraft mechanical and electromagnetic waves are different but they can Jordan many of the same ways this particular wave is called a transverse wave it carries energy along the spring by making it move at right angles to the direction of the energy flow ocean waves and most electromagnetic waves move transverse pattern the Crest is the highest point of a transverse wave and the trough is the lowest point the distance between the midpoint of the wave and the Crest is the amplitude a measure of how much energy the wave is carrying more energy is a greater amplitude the distance a wave travels in one cycle is one wavelength measured by finding the distance between two crests or troughs which can be measured by their frequency to the frequency is the number of waves that pass a given point in one second is measured in hertz or Waves per second and frequency is related to wavelength short wavelength high frequency right sound travels in compressional waves I'm like transverse wave displace matter back and forth in the same direction as the energy of the wave series of compressions the travel through the air does compressing air molecules hit your eardrum making it vibrate and sending sound signals to your brain like I said mechanical waves need something to travel through that's why you won't hear sounds if you find your open outer space of course if you bring your own air that's about enough on waves for now scary movie right so now what you're going to do you need to get he's a blank paper you need to follow the directions very carefully you going to get a piece of blank notebook paper you're going to number your paper 1 to 10 at the top of your paper for first name last name and then put waves Pop Quiz if you don't do this there will be points taken off your pop quiz so get your number 1 to 10 first name last name block and then put waves here Wego here's your quiz questions what do seismic waves and sound waves have in common Eider mechanic waves are electromagnetic waves see their somatic waves. They're permanent waves now in order for us to go to the next question I'm going to have to pick an answer I'm not saying if they answer really is a day or not I'm just always going to take a what does it mean when a waves amplitude increases its frequency also increases its moving through a denser medium its wavelength gets longer or its caring more energy what medium do seismic waves travel through the air to ground seawater deep outer space what do waves carry from place to place a energy but not matter energy and matter she matter but not energy D need energy or matter drive it away what happened to the molecule after it passes energy to the next molecule in the chain it continues moving the a vibrates rapidly from a buildup of energy becomes completely still or date it returns to its original resting position 6 how are electromagnetic waves different from mechanical waves electromagnetic waves need a medium to travel through mechanic the electromagnetic waves can travel through water mechanical waves can only travel through solid matter see electromagnetic waves can travel through empty space mechanical waves can't D electromagnetic boys are long chains of vibrating molecules mechanical waves art 7 which of the following are electromagnetic waves a water waves B radio waves C sound waves seismic waves what type of waves carry energy at a right angle to the direction of the energy flow a compression waves also called longitudinal transverse waves see sound waves D T waves night how is wavelength measured a SunTrust the crest from Crest to Crest see from Crest to trough to Crest or D from Crest to trough to Crest what can you infer about a wave Archie's me what can you infer about a wave with a short wavelength a it has a low amplitude the it has a high-amplitude see it has a high frequency or low frequency that's it that's your quiz you need to make sure you turn this into mrs. Harper remember I need first name last name block I also need for you to put waves Pop Quiz of top for you to receive all your points

Uploaded by Carmen Harper.

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