Physics 3Physics 3Sound & LightSound & Light

ppt. by Robin D. Seamon

SoundSound

Sound wave- longitudinal wave made by vibrating material, carried through the medium, transferring the Energy

Sound needs a medium, no sound in a vacuum/space

LAB: Tuning Forkp. 469

The Human EarOuter ear: funnel

Middle ear: hammer, anvil, stirrip (levers that increase the size of vibrations

Inner ear: vibrations to electrical signal to brain

Sound is:1. Collected (by outer ear)

2. Amplified (by middle ear: hammer, anvil, stirrup)

3. Converted to Electrical signals for the brain (by inner ear)

1.Sound waves vibrate the ear drum (lightly stretched membrane in middle ear)

2.Vibration of ear drum vibrates hammer-anvil-stirrup

3.Oval window vibrations create waves in liquid in cochlea

4.Movement of liquid causes tiny hair cells to bend

5.Bending of hair cells stimulates nerves, sends electrical signals to brain

HSW Sound/How we hear VIDEO (not saved)

HSW New Hearing Implant VIDEO

LAB: EAR DIAGRAMLAB: EAR DIAGRAMDirections: 1.Label the parts of the Human Ear.

2. Put numbers to show the order in which the sound reaches our brains.3. Circle the area that collects YELLOW; Circle the area that amplifies BLUE; Circle the area

that converts to electrical signals GREEN.

___ Inner ear

___ Auditory nerve

___ Middle ear

___ Hammer

___ Cochlea

___ Ear drum

___ Anvil

___ Stirrup

_1_ Outer ear

Human Ear

The The speedspeed of sound depends on the of sound depends on the 1. medium1. medium2. temperature2. temperature

Tap on desk.

AIR LIQUID SOLID

FasterSlower

Cool Warm

PitchPitch- how high or low a sound seems- how high or low a sound seems

FrequencyFrequency- (number of waves in a given - (number of waves in a given amount of time)amount of time)

batbat 2,000-2,000- 110,000 hz110,000 hz

porpoiseporpoise 75-75- 150,000 hz150,000 hz

CatCat 45-45- 64,000 hz64,000 hz

BelugaBeluga 1,000-1,000- 123,000 hz123,000 hz

ElephantElephant 16-16- 12,000 hz12,000 hz

HumanHuman 20-20- 20,000 hz20,000 hz

dogdog 67-67- 45,000 hz45,000 hz

Frequencies Heard by Different Animals

Doppler effectDoppler effect: apparent change in frequency of : apparent change in frequency of sound caused by motion of observer or source.sound caused by motion of observer or source.

Sound waves are moving forward/same direction of the train: Constructive interference makes it sound louder.

http://www.windows2universe.org/earth/images/doppler_effect_jpg_image.html&edu=high

Loudness-Loudness- how well a sound can be heard how well a sound can be hearddecibeldecibel (loudness unit) (loudness unit)

0 dB: softest humans can hear0 dB: softest humans can hear 120 dB: hurts 120 dB: hurts

LOUDER

oscilloscopeoscilloscope graphs representations of sound waves to ‘see’ them on computer

Echo strength-Echo strength- depends on reflecting surfacesoft pads & irregular shapes diffuse sound

EcholocationEcholocation- - use of reflected sounds to find food

HSW Sound: Infrasound & Echolocation VIDEO (4 min)

HSW Elephant Communication (3 min)

Ultrasonography- use echoes to ‘see inside’

http://www.virtualmedicalcentre.com/healthinvestigations.asp?sid=8&title=Ultrasound-(Ultrasound-Scanning-or-Sonography-and-Doppler)

http://www.nlm.nih.gov/medlineplus/ency/images/ency/fullsize/1058.jpg

Sonic boom-Sonic boom- explosive sound explosive sound when shock wave reaches when shock wave reaches your earyour ear

Noise makes sound waves, pushing air out, as plane moves forward, it meets up with the sound wave. If faster than the sound wave, plane leaves the sound wave behind, creating a sonic wave (BOOM)

HSW Sonic Boom (8 min)

http://news.nationalgeographic.com/news/2005/08/0808_050808_soundbarrier.html

Sound quality- the result of the blending of several pitches through interference

Noise- any sound; random mix of frequencies or pitches

MUSICFundamental: lowest resonant frequencyovertones: higher resonance (2X)second overtone: higher resonance (3X)third overtone: higher resonance (4X)

TEXTBOOK: Holt Science & Technology Grade 6

String instrument played with vibration of played with vibration of string/metalstring/metal

Wind instrument played with the vibration played with the vibration of air through tube/holeof air through tube/hole

Percussion instrument played by played by pounding rhythm; impactpounding rhythm; impact

ADVANCE

BACK TEXTBOOK: Holt Science & Technology

Grade 6

BACK TEXTBOOK: Holt Science & Technology

Grade 6

BACK

TEXTBOOK: Holt Science & Technology Grade 6

Mini TestMini Test Did You Hear a Did You Hear a Sound?Sound? Mini DiagramMini Diagram ObservationsObservations

Feel? Hear?Feel? Hear? Type of MaterialType of Material

knock on the knock on the chalkboard while chalkboard while partner listenspartner listens

           

tap the desk with a tap the desk with a ruler while partner ruler while partner listenslistens

           

ring a bell under ring a bell under waterwater            

hold a tuning fork hold a tuning fork under waterunder water            

say "hello" to a say "hello" to a friend across the friend across the roomroom

           

hold a balloon hold a balloon against a speaker against a speaker as music is playedas music is played

           

SOUND LABSOUND LAB1. Perform each mini-test.

2. Complete each column with each min-test

HEADER:

LightLight

1. Light is refracted through the cornea

2. Light passes through pupil (opening)

3. Iris controls size of pupil (colored part)

4. Light goes through lens, refracts light to focus an image on back of eye

5. Receptors in retina (back of eye) pick up light with rods & cones

6. Nerves attached to rods & cones send info to brain

HUMAN EYE

RodsRods: sense dim light: sense dim light

ConesCones: sense bright light: sense bright light

___Iris

___Lens

___Optic nerve

___Retina

___Cornea

___Pupil

LAB: EYE DIAGRAMDirections: 1.Label the parts of the Human EYE.

2. Put numbers to show the order in which the image reaches our brains.

All humans have a blind spot right near the middle of their pupil. To find it, hold your arm out in front of you, but off to the side, with your index finger extended. Cover one of your eyes, stare straight ahead with the other and slowly bring your extended finger closer to the middle of your field of vision. As your finger approaches you should see your fingertip disappear when it reaches the blind spot. Mind = blown.

Near sightednessNear sightedness person person can see something clearly if it can see something clearly if it is nearby; blurry vision of is nearby; blurry vision of things far away; eye is too things far away; eye is too longlong

Far sightednessFar sightedness person can person can see something clearly far see something clearly far away; blurry vision of things away; blurry vision of things up close; eye is too shortup close; eye is too short

Electromagnetic wave- Electromagnetic wave- wave that can travel wave that can travel through empty space & matter; changing of through empty space & matter; changing of electric and magnetic fieldselectric and magnetic fields

Electric field

Magnetic field

http://www.isvr.soton.ac.uk/spcg/Tutorial/Tutorial/Tutorial_files/light1.gif

KEY:

Electric field: surrounds a charged object N-S

Magnetic field: surrounds all magnets; attracts objects to it

Electromagnetic wave- vibration of electrically charged particle; makes electric field vibrate, making a vibrating magnetic field

Radiation: transfer of Energy as electromagnetic waves

Radiation LINK HSW VIDEO (2 min)

--Light travels about 300,000,000 m/s--Light travels about 300,000,000 m/s

--8.3 min for light to travel from sun to Earth--8.3 min for light to travel from sun to Earth

----Visible lightVisible light: electromagnetic waves that humans : electromagnetic waves that humans can seecan see

Light wavelength: 100 X thinner

than the human hair!

Law of reflectionLaw of reflection incidence equals reflectionincidence equals reflection

Regular reflection light beams reflected at the same angle (shinier)

Diffuse reflection light beams reflect at different angles (duller)

http://www.worsleyschool.net/science/files/reflectionlaw/page.html

We see We see objects objects because a light is reflecting off of it because a light is reflecting off of it into our eyes. into our eyes. (illumination)(illumination)

We see a We see a light sourcelight source even in the dark because it even in the dark because it goes directly into your eyes.goes directly into your eyes.

Room with a lamp on Room with a lamp off

Absorption: transfer of light waves to particles of matter

air particles absorb some of the light Energy… ray becomes dimmer farther out

Scattering: an interaction of light with matter that causes light to change its Energy, direction of motion, or both

RefractionRefraction: bending of light: bending of light

Lens:Lens: transparent object that refracts light to form transparent object that refracts light to form an imagean image

Convex lens

center bulges out

Concave lens

center buckles in

Transmission: passing of light through matter

1. transparent clear

2. translucent slightly cloudy

3. opaque light cannot pass through

TranslucentTranslucent TransparentTransparent OpaqueOpaque

    

   

LAB: Translucent, Transparent, OpaqueLAB: Translucent, Transparent, OpaqueMaterials:cardboardwoodmottled glass *paper towelfeltStyrofoam trayscolored plastic lidstin foil"almost" clear plastic lidsplastic wrapclear glass *"bubble" packing materiallaminating material tissue paperwaxed paper clear plastic lidsconstruction papercloth

DEFINE:

Translucent _______________________________________________________________________________

Transparent_______________________________________________________________________________

Opaque__________________________________________________________________________________

Header:

Prism:Prism: clear piece of glass or water that refracts white light into the whole color spectrum

--refracts light twice, breaking up the spectrum

HSW Video: Prisms (1:45)

HSW Video: A look at Light (1:45)

ROY G BIV

Long

Short

LIGHT ISLIGHT IS::

1.1. TransmittedTransmitted

2.2. ReflectedReflected

3.3. AbsorbedAbsorbed

COLOR: the color we see is determined by which wavelength is bounced back to our eye

Black- all colors are absorbed

White- all colors are reflected to you

LIGHT THEORY

PIGMENT… PaintingPIGMENT… Painting

Pigment: material that gives a substance color by absorbing some & reflecting others (chlorophyl, melanin, paint)

Color PrintsColor Prints

LAB: PrismsLAB: Prisms

Reflection: when the wave bounces back towards the source

Refraction: waves are deflected when they go through a source & are usually bent

Diffraction: when a wave goes through a small hole and has a flared out geometric shadow of the slit or seems to bend around an object; makes shadow blurry

Diffraction:Diffraction:

Constructive interferenceConstructive interference wave crests & troughs wave crests & troughs line up, making it a stronger waveline up, making it a stronger wave

IN NATURE:IN NATURE:

http://www.microscopyu.com/articles/polarized/interferenceintro.html

www.sgmt.at/refere/Hologram.htm

Destructive interference creates shadow or blurry edges

Optical IllusionsOptical Illusions

Optical Illusions

Optical Illusions

http://www.colorbasics.com/Optical-Illusions/

LINK: They disappear!

x

HUMAN EYEHUMAN EAR

Human Ear

Optical Illusions:

1.LINK to Optical Illusions

2.http://www.colorbasics.com/Optical-Illusions/

Color Blindness Test LINK

• HSW: Exploring Sound (23 min) not saved

• HSW: Exploring Light ( 3 min) not saved

• Physical Science: Light ( 20 min)

• Physical Science: Sound ( 20 min)

• HSW How Vision Works Car Chase (4 min) not saved

• HSW