Presentation on theme: "WAVES A wave is a rhythmic disturbance that TRANSFERS ENERGY."— Presentation transcript:
1 WAVESA wave is a rhythmicdisturbance thatTRANSFERS ENERGY.
2 We are going to study 2 kinds of waves: Transverse Compressional Both kinds of waves transfer energy.They just transfer theenergy in different ways!
3 TRANSVERSE WAVE Transverse waves carry energy by moving in an up and down motion.CRESTS- High points on a transverse waveTROUGHS- Low points on a transverse waveWAVELENGTH- Distance from crest tocrest or trough to troughAMPLITUDE is the distance from restingposition to the crest or trough.
5 Frequency of a wave is the number of crests to pass a point in 1 second.Look at the 2 waves below.Which one has a higher frequency?Yes, the second one has more crests,therefore a higher frequency!
6 1. 2. Is there any relationship between frequency and wavelength? Lets look at 2 different waves.The first wave has a highfrequency and a short wavelength.1.The second wave has a lowfrequency and a long wavelength.2.So, the higher the frequency, the shorter the wavelength!
7 fast a wave is traveling? How do we figure out howfast a wave is traveling?Velocity = Wavelength x FrequencyYOU MUST KNOW YOUR UNITS!!Velocity is measured in meters per second. (m/s)Wavelength is measured in meters. (m)Frequency is measured in hertz. (hz)
8 Let's Practice!Example : What is the velocity of a wave witha frequency of 15,000 hertz and a wavelengthof 4 m?Step 1: Write the formula.Velocity = Frequency x WavelengthStep 2: Plug in the numbers from the problem.Velocity = 15,000 hz x 4 mStep 3: Calculate the answer and be sureto add a unit!60,000 m/s
9 REFLECTION: Reflection is when a wave strikes a barrier and is bounced back.Examples: Looking in a mirroror hearing an echo!The angle in =the angle out!
10 REFRACTION Refraction is the bending of light waves as they travel from onemedium to another.Example: A prism making a rainbow.Light waves bendingas they enter water.
11 Parts of the Electromagnetic Spectrum The sun releases all parts of the EM spectrum.They include:Radio wavesRadar wavesMicrowavesInfraredVisible LightUltravioletX- RaysGamma Rays
12 Electromagnetic Spectrum All parts of the electromagneticspectrum have 3 things in common:They are all TRANSVERSE WAVES.They all travel at the speed of light.(300,000 km/s)3. They do not need a medium to travel.What is a medium?A solid, liquid, or a gas!
13 frequencies and wavelengths! Electromagnetic SpectrumWhat is the only difference betweenparts of the electromagnetic spectrum?The only difference between theparts of the electromagnetic spectrumis that they all have differentfrequencies and wavelengths!
14 Let's Talk about Visible Light Visible Light is part of the EM Spectrumand can be broken down into itscomponent colors.REDORANGE YELLOW GREEN BLUEINDIGOVIOLETThe only difference between the colors is that they all have different wavelengths and frequency.
15 Why does a red shirt appear red? Because it reflects the wavelength thatrepresents red and absorbs the rest.Why do black pants appear black?Because they absorb all the wavelengths!This is also why wearing black in the summermakes you feel warm.Why do white socks appear white?Because they reflect all the wavelengths.This is also why we wear white in the summer.To try and stay cool!
16 Transmitting Light The type of matter determined how much light will be transmitted through.Opaque Objects: Transmit no light.We cannot see through them.2. Transparent Objects: Transmit all light.We see easily through them.3. Translucent Objects: Transmit some light.We can only see outlines.
17 Sound is a Compressional Wave Remember:Light is an transverse wave!Sound is a Compressional WaveCompressional Waves carry energy bymoving in a side to side motion.Compression – Areas of a compression wavethat are close together.Rarefaction- Areas of a compression wavethat are spread apart.Wavelength- The distance betweencompressions.
19 Sound is a vibration through a medium Sound is a compressional wave. UNLIKE LIGHT, SOUND MUST HAVEA MEDIUM TO TRAVEL!!
20 Speed of Sound How fast sound travels depends on 2 things: The Medium- Sound travels fastestthrough SOLIDS!2. Temperature- Sound travels slightly fasterin warm temperaturesSpeed of Sound in “regular” air is 344 m/s!
21 Speed = Distance Time Calculating Speed of Sound Remember your units! Speed is in meters per second.Time is in seconds.Distance is in meters.
22 THE HIGHER THE FREQUENCY, How are frequency and pitch related?Pitch is the highnessor lowness of a sound.THE HIGHER THE FREQUENCY,THE HIGHER THE PITCH!
23 Differences Between Sound and Light Light travels much faster. Light 300,000 km/sSound 344 m/s2. Sound needs a medium and light does not.3. Sound is a compressional wave andlight is a transverse wave.