UNIT 4

CHARACTERISTICS OF WAVES

CHAPTER 10 (HS)/CHAPTER 15 (8TH GR)

Big Idea:Waves

Essential Question:What type of wave is a sound wave?

IB Question:Are you doing the wave?

GEORGIA PERFORMANCE STANDARDSSPS9. Students will investigate the properties of waves.

a. Recognize that all waves transfer energy.b. Relate frequency and wavelength to the energy of different types of electromagnetic waves and

mechanical waves.c. Compare and contrast the characteristics of

electromagnetic and mechanical (sound) waves.d. Investigate the phenomena of reflection,

refraction, interference, and diffraction.e. Relate the speed of sound to different mediums.

f. Explain the Doppler Effect in terms of everyday interactions.

WAVESWave—a repeating movement of disturbance that transfers energy through matter or space.~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~All waves carry energy without transporting matter from place to place.

molecules pass energy along to neighbor molecules who then pass energy to neighborall waves are produced by vibrationswaves will travel as long as there is energy

to carry.

WAVES

Waves move energy… …not matter

Medium—matter though which a wave travels•A medium can be solid, liquid, gas or a combo•Not all waves need a medium to travel—light and radio waves travel through space

WAVES

WAVESMechanical Waves—waves that can only travel through a medium.

Transverse Waves Compression WavesMatter moves back and forth at right angles to direction that wave travels

Matter in medium moves in the same direction that wave travels

WAVESStudents will complete a concept map to be placed in their interactive notebook.

Big Idea:Features of Waves

Essential Question:Which is faster sound waves or light

waves?

IB Question:Are you doing the wave?

GEORGIA PERFORMANCE STANDARDSSPS9. Students will investigate the properties of waves.

a. Recognize that all waves transfer energy.b. Relate frequency and wavelength to the energy of different types of electromagnetic waves and

mechanical waves.c. Compare and contrast the characteristics of

electromagnetic and mechanical (sound) waves.d. Investigate the phenomena of reflection,

refraction, interference, and diffraction.e. Relate the speed of sound to different mediums.

f. Explain the Doppler Effect in terms of everyday interactions.

FEATURES OF WAVES

Parts of WavesTransverse Waves have crests—the highest points, and troughs—the lowest points of waves.

Compressional waves have dense regions (coils close together) called compressions and less dense regions called rarefactions.

FEATURES OF WAVESWavelength (λ)—distance between one point on wave and similar point nearest to it. (crest to crest, trough to trough, compression to compression, or rarefaction to rarefaction)

----1λ---- -1λ--1λ-

WAVELENGTH OF

WAVE

DECREASES AS

FREQUENCY

INCREASES

FEATURES OF WAVESFrequency—number of wavelengths that pass a fixed point each second (hertz—Hz)

Calculating Wave Speed

Wave speed (m/s) = frequency (Hz) x wavelength (m)

V = f λ

FEATURES OF WAVES

Amplitude—a measure of energy in a wave, the more energy a wave carries greater amplitude

Transverse waves—Distance from crest or trough to normal position

Compression waves—the denser the compressions the larger the amplitude

ON THE LEFT SIDE OF YOUR NOTEBOOK

Page 516

Draw and label a transverse wave and a compression/longitudinal wave.

You must identify crest, trough, wavelength, amplitude, compression, rarefaction, normal/rest position

WAVES

•Waves video https://www.youtube.com/watch?v=XK8uTaFfZnw•Wave lab with Slinky's•Wave vocabulary Quiz

Big Idea:Behavior of Waves

Essential Question:What do an echo, a shadow and your

reflection have in common?

IB Question:Are you doing the wave?

GEORGIA PERFORMANCE STANDARDSSPS9. Students will investigate the properties of waves.

a. Recognize that all waves transfer energy.b. Relate frequency and wavelength to the energy of different types of electromagnetic waves and

mechanical waves.c. Compare and contrast the characteristics of

electromagnetic and mechanical (sound) waves.d. Investigate the phenomena of reflection,

refraction, interference, and diffraction.e. Relate the speed of sound to different mediums.

f. Explain the Doppler Effect in terms of everyday interactions.

BEHAVIOR OF WAVESLaw of Reflection—the angle of incidence (i) of a wave is always equal to the angle of reflection (r)

Reflection—occurs when a wave strikes an object and bounces off of it—all types of waves can be reflected (ex. Sound, water, & light)

Normal r

i

BEHAVIOR OF WAVESRefraction—bending of a wave caused by a change in its speed as it moves from one medium to another.

Pencil in water looks broken due to refraction.

The greater the change in speed the more the wave bends.

BEHAVIOR OF WAVESDiffraction—an object causes a wave to change direction and bend toward it.

Both refraction and diffraction cause waves to bend; however, refraction occurs when waves pass through an object while diffraction occurs when waves pass around an object.

Constructive vs. DestructiveWaves add

- - - - - - - - - - - - - - - - - - - - - - - - - - - - -- - - -- - - - -- -

Waves subtract

-- - - - - - - - - - - - - - - - -- - - - -- - - - - - - - - - - -- - - - -

BEHAVIOR OF WAVESInterference—when two or more waves overlap and combine to form a new wave.

https://www.brainpop.com/science/energy/waves/ https://www.brainpop.com/science/energy/refractionanddiffraction/

Big Idea:ELECTROMAGNETIC WAVES

Essential Question:What causes electromagnetic waves?

IB Question:Are you doing the wave?

GEORGIA PERFORMANCE STANDARDSSPS9. Students will investigate the properties of waves.

a. Recognize that all waves transfer energy.b. Relate frequency and wavelength to the energy of different types of electromagnetic waves and

mechanical waves.c. Compare and contrast the characteristics of

electromagnetic and mechanical (sound) waves.d. Investigate the phenomena of reflection,

refraction, interference, and diffraction.e. Relate the speed of sound to different mediums.

f. Explain the Doppler Effect in terms of everyday interactions.

ELECTROMAGNETIC WAVESElectromagnetic Waves—made by vibrating electric charges and can travel through space.

Frequency of electromagnetic waves is the number of vibrations per second (Hz)

Electromagnetic spectrum—the entire range of electromagnetic wave frequencies

ELECTROMAGNETIC WAVESThe Electromagnetic Spectrum Includes:

Radio Waves —low frequency waves with wavelengths at about 1-10 cm (radio stations, microwaves, radar)

Infared Waves —have slightly higher frequency than radio waves (remote control, warmth of fire, satellites)

ELECTROMAGNETIC WAVESThe Electromagnetic Spectrum Includes:

Visible Light—range of electromagnetic waves you can detect with your eyes (ROYGBIV—different colors have different wavelengths)

Ultraviolet waves—frequencies slightly higher than visible light (sunburns, vitamin D production, fluorescent materials absorb it, kills bacteria)

ELECTROMAGNETIC WAVESThe Electromagnetic Spectrum Includes:

X-rays & Gamma Rays—ultra-high frequencies that can travel through matter, damage cells (bone images, radiation therapy, production of superhero—Hulk)

Big Idea:Communicating with Radio Waves

Essential Question:What does “radar” stand for?

IB Question:Are you doing the wave?

GEORGIA PERFORMANCE STANDARDSSPS9. Students will investigate the properties of waves.

a. Recognize that all waves transfer energy.b. Relate frequency and wavelength to the energy of different types of electromagnetic waves and

mechanical waves.c. Compare and contrast the characteristics of

electromagnetic and mechanical (sound) waves.d. Investigate the phenomena of reflection,

refraction, interference, and diffraction.e. Relate the speed of sound to different mediums.

f. Explain the Doppler Effect in terms of everyday interactions.

COMMUNICATING WITH RADIO WAVESRadio transmission—radio converts electromagnetic waves into sound waves.

Each radio station is assigned a particular radio frequency for their broadcast—this specific frequency is called the carrier wave.

COMMUNICATING WITH RADIO WAVESCarrier waves can transmit a signal in one of two ways:

Amplitude modulation (AM)

Frequency modulation (FM)

AM radio broadcasts info by varying the amplitude of the carrier wave.

FM radio varies the frequency of carrier waves

COMMUNICATING WITH RADIO WAVESTelevision—audio is sent by FM radio waves and video is sent by AM radio signals

Cathode—ray tubes—produce images you see in TV—

surface is covered by spots that glow red, green, or blue when struck by electron beams.

COMMUNICATING WITH RADIO WAVESTelephones—electrical signal creates radio wave that is transmitted to and from a microwave tower.

COMMUNICATING WITH RADIO WAVESGlobal Positioning Systems (GPS)—system of satellites, ground stations an receivers that receive high frequency microwave signals, amplify it and return it to Earth.

Big Idea:Sound

Essential Question:Why does sound need to travel through

a medium?

IB Question:Do you hear me now?

GEORGIA PERFORMANCE STANDARDSSPS9. Students will investigate the properties of waves.

a. Recognize that all waves transfer energy.b. Relate frequency and wavelength to the energy of different types of electromagnetic waves and

mechanical waves.c. Compare and contrast the characteristics of

electromagnetic and mechanical (sound) waves.d. Investigate the phenomena of reflection,

refraction, interference, and diffraction.e. Relate the speed of sound to different mediums.

f. Explain the Doppler Effect in terms of everyday interactions.

SOUNDHow the Ear WorksHow Old Are Your Ears