12345671234567 Waves carry energy from one place to another. Transverse and longitudinal waves exist in mechanical media, such as springs and ropes, and.

12

34

5

6

7

Waves carry energy from one place to another.Transverse and longitudinal waves exist in mechanical media, such as springs and ropes, and in the Earth as seismic waves.Wavelength, frequency and wave speed are related.Sound is a longitudinal wave whose speed depends on the properties of the medium in which it propagates.Radio waves, light and X-rays are different wavelength bands in the spectrum of electromagnetic waves, the speed of which in a vacuum is approximately 3 x 108m/s, and less when passing through other media.Waves have characteristic behaviors, such as interference, diffraction, refraction and polarization.Beats and the Doppler Effect result from the characteristic behavior of waves.

Waves have characteristic properties that do not depend on the type of wave.

What are they?What are they? Are these the same things?Are these the same things?

Radio Waves Microwaves Infrared Visible Light

Ultraviolet Light X-rays Gamma Rays

Before we answer that question, lets review Before we answer that question, lets review some metric units & scientific notation. some metric units & scientific notation.

Prefix Symbol Value Description

pico p 10-12 1 picometer, (pm) = 0.000000000001 m

nano n 10-9 1 nanometer, (nm) = 0.0000000001 m

micro µ or u 10-6 1 micrometer (µm) = 0.000001 m

milli m 10-3 1 millimeter (mm) = 0.001 m

centi c 10-2 1 centimeter (cm) = 0.01 m

deci d 10-1 1 decimeter (dm) = 0.1 m

NONE NONE 1 normal units without prefixes

kilo k 103 1 kilohertz (kHz) = 1000 Hz

mega M 106 1 megahertz (MHz) = 1,000,000 Hz

giga G 109 1 gigahertz (GHz) = 1,000,000,000 Hz

tera T 1012 1 terahertz (THz) = 1,000,000,000,000 Hz

Are all parts of the electromagnetic spectrum and are fundamentally the same thing. They are all electromagnetic radiation.

The electromagnetic spectrum can be expressed in terms of wavelength, frequency, or energy.

Radio, microwaves, infrared, visible light, ultraviolet, X-rays, gamma rays

v = f x v = f x λλ

v = f x v = f x λλ 300,000,000 m/s = speed of light300,000,000 m/s = speed of light340 m/s = speed of sound340 m/s = speed of sound

3*103*108 8 m/sm/s = 3*10= 3*1055 Hz x 1*10 Hz x 1*103 3 mm

Speed of light in a vacuum 299,792,458 m/s (1,079,252,849 km/h)

c = 3×10c = 3×1088 m/s m/s (Approximate Value)

v = f x v = f x λλ 300,000,000 m/s = speed of light300,000,000 m/s = speed of light340 m/s = speed of sound340 m/s = speed of sound

EnergyEnergy E = h x fE = h x f

(Planks Constant) h = 6.626 × 10h = 6.626 × 10-34-34 joule·seconds joule·seconds h = 4.136 x 10 h = 4.136 x 10-15-15 eV·seconds eV·seconds

Higher Higher EnergyEnergy

Lower Lower EnergyEnergy

1 eV = 1.602 ×10−19 J.

E = h x fE = h x f h = 6.626 × 10h = 6.626 × 10-34-34 J·sec J·sec (Planks Constant)

EM Wave Freq (Hz) h x f = E Energy

Television 108 Hz (6.626 x 10-34) x (108) 6.6 x10-26 J

Infrared 1014 Hz (6.626 x 10-34) x (1014) 6.6 x10-20 J

Ultra Violet 1016 Hz (6.626 x 10-34) x (1016) 6.6 x10-18 J

X-Rays 1018 Hz (6.626 x 10-34) x (1018) 6.6 x10-16 J

Energy in Electro Magnetic Waves

What about a Microwave at 3,000 MHz (3.0 x 10What about a Microwave at 3,000 MHz (3.0 x 1099 Hz)? Hz)?

NOTE: a 1KW microwave oven with a frequency of 2999 MHz produces 5.0 x 1029 photons per second.

If a single microwave (photon) has a frequency of 3,000 MHz, how much energy will it have?

E = h x fE = h x f h = 6.626 × 10h = 6.626 × 10-34-34 J·sec J·sec

E = (6.626 × 10E = (6.626 × 10-34-34 J·sec) x (3.0 x 10 J·sec) x (3.0 x 1099 Hz) Hz)E = 1.99 x 10E = 1.99 x 10-24-24 J per photon J per photon

E = (1.99 x 10E = (1.99 x 10-24-24 J) x (5.0 x 10 J) x (5.0 x 102929))

= 994,000 J per second= 994,000 J per second

KE = ½ mv2

994,000 J = ½ * 1179 Kg * 41 m/s994,000 J = ½ * Toyota * 90 mph994,000 J = ½ * Toyota * 90 mph

EM (Hz) Energy

TV 108 Hz 6.6 x10-26 J

IR 1014 Hz 6.6 x10-20 J

UV 1016 Hz 6.6 x10-18 JX-Rays 1018 Hz 6.6 x10-16 J

Note: most microwaves operate at 2,450 MHz not 2,999 MHz

The above image shows the Carbon Monoxide (CO) gases in our Milky Way galaxy.

http://science.hq.nasa.gov/kids/imagers/ems/radio.html

Cellular

Radio WavesRadio Waves - Longest wavelengths in the EM spectrum - Longest wavelengths in the EM spectrum

Radio waves can penetrate the earths atmosphere – radio astronomy

Waves can be longer than a ten football fields or as short as a football. Waves can be longer than a ten football fields or as short as a football.

100 kHz 1 GHz

Radio WavesRadio Waves - Common frequency bands include the following: - Common frequency bands include the following: -AM radio - 535 kilohertz to 1.7 megahertz -Short wave radio - bands from 5.9 megahertz to 26.1 megahertz -Citizens band (CB) radio - 26.96 megahertz to 27.41 megahertz -Television stations - 54 to 88 megahertz for channels 2 through 6 -FM radio - 88 megahertz to 108 megahertz -Television stations - 174 to 220 megahertz for channels 7 through 13

Every wireless technology you can imagine has its own little band:Every wireless technology you can imagine has its own little band:-Garage door openers, alarm systems, etc. - Around 40 megahertz -Standard cordless phones: Bands from 40 to 50 megahertz -Baby monitors: 49 megahertz -Radio controlled airplanes: Around 72 megahertz, which is different from... -Radio controlled cars: Around 75 megahertz -Wildlife tracking collars: 215 to 220 megahertz -MIR space station: 145 megahertz and 437 megahertz -Cell phones: 824 to 849 megahertz -New 900-MHz cordless phones: Obviously around 900 megahertz! -Air traffic control radar: 960 to 1,215 megahertz -Global Positioning System: 1,227 and 1,575 megahertz -Deep space radio communications: 2290 megahertz to 2300 megahertz

Radio WavesRadio Waves - Longest wavelengths in the EM spectrum - Longest wavelengths in the EM spectrum

CentimetersCentimeters

100 kHz 1 GHz

Microwave Ovens

Shorter microwaves are used in remote sensing. These microwaves are used for radarradar like the doppler radar used in weather forecasts. Microwaves, used for radar, are just a few inches long

Microwaves are good for transmitting informationtransmitting information from one place to another because microwave energy can penetrate haze, light rain and snow, clouds, and smoke. (point - to - point)

Radar is an acronym for "radio detection and ranging"

Special cameras and film that can detect differences in temperature, and then assign different brightnesses or false colors to them.

750 nm1 x1012 Hz 4 x1014 Hz

Far infrared waves are thermalthermal. In other words, we experience this type of infrared radiation every day in the form of heat !form of heat ! The heat that we feel from sunlight, a fire, a radiator or a warm sidewalk is infrared

Shorter, near infrared waves are not hot at all - in fact you cannot even feel them. These shorter wavelengths are the ones used by your TV's remote TV's remote control. control.

Which EM wavelengths can make it through our Atmosphere?

H e a tH e a t

Visible light can easily penetrate the atmosphere, Infrared can not penetrate (or escapeor escape) as easily.

Though electromagnetic waves exist in a vast range of wavelengths, our eyes are sensitive to only a very narrow band – visible light. (approximately 400 – (approximately 400 – 700 nm)700 nm)

Color Wavelength

violet 380–450 nm

blue 450–495 nm

green 495–570 nm

yellow 570–590 nm

orange 590–620 nm

red 620–750 nm

Though these waves are invisible to the human eye, some insects, like bumblebees, can see them!

400 nm 10 nm1 x1015 Hz 3 x1016 Hz

Health concerns for UV exposure are mostly for the range 290-330 nm in wavelength, the range called UVBUVB. The most effective biological wavelength for producing skin burns is 297 nm297 nm

UVA 400 nm – 315 nm (Black Lights)

UVB 315 nm – 280 nm (Sun Burn)

UVC 280 nm – 100 nm (germicidal)

A sterilization method that uses ultraviolet (UV) light to break down micro-organisms. (Food, air and water purification.)

Because your bones and teeth are dense and absorb more X-rays then your skin does, silhouettes of your bones or teeth are left on the X-ray film while your skin appears transparent. Metal absorbs even more X-rays.

Many things in space emit X-rays, among them are black holes, neutron stars, binary star systems, supernova remnants, stars, the Sun, and even some comets!

We usually talk We usually talk about X-rays in about X-rays in terms of their terms of their energy rather than energy rather than wavelength. wavelength.

1 x1016 Hz 1 x1018 Hz

Many things in deep space give off X-rays. Many stars Many things in deep space give off X-rays. Many stars are in binary star systems - which means that two stars are in binary star systems - which means that two stars orbit each other. When one of these stars is a black hole orbit each other. When one of these stars is a black hole or a neutron star, material is pulled off the normal star. or a neutron star, material is pulled off the normal star. This materials spirals into the black hole or neutron star This materials spirals into the black hole or neutron star and heats up to very high temperatures. When and heats up to very high temperatures. When something is heated to over a million degrees, it will give something is heated to over a million degrees, it will give off X-rays! off X-rays!

The above image is an artist's conception of a binary The above image is an artist's conception of a binary star system - it shows the material being pulled off the star system - it shows the material being pulled off the red star by its invisible black hole companion and into an red star by its invisible black hole companion and into an orbiting disk. orbiting disk.

1 x1018 Hz

Smallest wavelengthsSmallest wavelengths and the and the

most energymost energy of any other wave in of any other wave in the Electromagnetic spectrum.the Electromagnetic spectrum.

Gamma-rays can kill living cells, a fact which medicine uses to its advantage, using gamma-rays to kill cancerous cells.

These waves are These waves are generated by generated by radioactive atoms and radioactive atoms and in nuclear explosions. in nuclear explosions.

Gamma-ray bursts can release more energymore energy in 10 seconds than the Sun will in 10 seconds than the Sun will emit in its entire 10 billion-year lifetime!emit in its entire 10 billion-year lifetime! So far, it appears that all of the bursts we have observed have come from outside the Milky Way Galaxy. The sources of these enigmatic high-energy flashes remain a mystery.

Gamma Rays – ENERGITICALLY Interesting Facts

By solving the mystery of gamma-ray bursts, scientists hope to gain further knowledge of the origins of the Universe, the rate at which the Universe is expanding, and the size of the Universe.

Smallest wavelengths Smallest wavelengths

Highest frequencyHighest frequency

Most energy Most energy

E = h x fE = h x f

v = f x v = f x λλ

What is the only thing that we (humans) can see?

A very small band of the A very small band of the electromagnetic spectrum electromagnetic spectrum between 380 – 750 nm between 380 – 750 nm

(400 – 700 nm) (400 – 700 nm)

LIGHTLIGHT

LIGHTLIGHT

LIGHTLIGHT

Sight & Light

Rods & Cones Rods & Cones send signals to send signals to the brainthe brain

What is occurring between our eyes and the objects that we see?

Is there anything traveling between our eyes and the objects?

What do you see? WAIT - Don’t say it out loud.What do you see? WAIT - Don’t say it out loud.

An electromagnetic wave with a wavelength of approx. 600 nm

White Light

AllAll visivisible

ble wavwaveleelengtngthshs

Energy traveling

as EM waves

through a

medium (or a

vacuum)

Until the EM waves hit an

object

What do the EM What do the EM waves do when they waves do when they

hit an object?hit an object?

http://www.ronbigelow.com/articles/color-perception-2/perception-2.htmReflected light

Daylight -Daylight -

Not a perfect Not a perfect spectrumspectrum

We see the wavelengths of light that are reflected off of the object.

All other wavelengths are absorbed by the object.

The wavelengths of light we seeThe wavelengths of light we see

http://www.explorescience.com/index.cfm?method=cResource.dspView&ResourceID=652

Color absorption by different glass http://www.webexhibits.org/causesofcolor/4.html

Do we see all of wavelengths of visible light at the same intensity?

Daylight bulb Incandescent bulb

Mercury Lamp

Sodium Lamp (low pressure)

Sodium Lamp (high pressure)

Did the actual Did the actual paint on the paint on the walls change?walls change?

http://hyperphysics.phy-astr.gsu.edu/hbase/quantum/atspect.html

Spectral lines

Neon Spectrum

What is the perceived color of the light source?

Perceived color Perceived color VSVS actual actual wavelengths present in the wavelengths present in the

light source.light source.

Not every wavelength present

What are the wavelengths of these What are the wavelengths of these spectral linesspectral lines??

|||||||||||||||||||||||||||||||||||||||||| 7 | 6 | 5 | 4 || | | | | | | | |

Today’s Lab

Determine the wavelengths that are present in six

different light sources

|||||||||||||||||||||||||||||||||||||||||| 7 | 6 | 5 | 4 || | | | | | | | |

Lab Report

Dark R

ed

Yellow

/Orange

Blue

Visible Light & Wavelength

Let us return to the lab we Let us return to the lab we did last classdid last class

Wave speed did Wave speed did notnot change change

RR +

+

BB

BB +

+

GG

RRGG BB

RR +

+

GG

http://www.phy.ntnu.edu.tw/ntnujava/index.php?topic=39 Simulation – mixing colors of light (over lapping)

Green – Magenta

Red – Cyan

Blue – Yellow

Colors of Light

|||||||||||||||||||||||||||||||||||||||||| 7 | 6 | 5 | 4 || | | | | | | | |

Helium Spectral LinesHelium Spectral Lines – Lab Results – Lab Results

|||||||||||||||||||||||||||||||||||||||||| 7 | 6 | 5 | 4 || | | | | | | | |

Perceived color = pink?

Note that the intensity (the brightness) of each band is different

Fluorescent Tube Spectral Lines - Results

Hallway Hallway Fluorescent Fluorescent

lightslights

Note the Note the differences in differences in

intensityintensity

400 nm 700 nm

Natural Light (sun light on sky

bridge)

Incandescent Bulb (night light)

Fluorescent Bulb - older typeolder type - (single

tube)

Fluorescent Bulb - Newer typeNewer type -

(hallway lights)

Fluorescent Bulb - Energy SaverEnergy Saver -

(not in class)

Hydrogen Spectral Lines – Lab Results

400 nm 500 nm 600 nm 700 nm

Wavelength(nm)

Relative Intensity

Transition Color

410.174 15 6 -> 2 Violet

434.047 30 5 -> 2 Violet

486.133 80 4 -> 2 Bluegreen (cyan)

656.272 120 3 -> 2 Red

656.2852 180 3 -> 2 Red

Bohr model of an atom

ExcitedExcited

GroundGround

http://micro.magnet.fsu.edu/primer/java/fluorescence/exciteemit/ Electron Excitation and Emission (at a lower energy)

http://phet.colorado.edu/new/simulations/sims.php?sim=Models_of_the_Hydrogen_Atom Photon Absorption & Emission for a hydrogen atom

Creating an Emission Line (Spectral LinesSpectral Lines)

Hydrogen Helium Neon

Spectral Lines of various elements

ColorWavelength

(nm) h x f = E

Violet 410.174 (6.626 x 10-34) x (1.36 x 10-15 Hz)

Violet 434.047 (6.626 x 10-34) x (1.45 x 10-15 Hz)

Bluegreen (cyan)

486.133 (6.626 x 10-34) x (1.62 x 10-15 Hz)

Red 656.272 (6.626 x 10-34) x (2.19 x 10-15 Hz)

Red 656.2852 (6.626 x 10-34) x (2.19 x 10-19 Hz)

400 nm 500 nm 600 nm 700 nm

E = h x fE = h x fh = 6.626 × 10h = 6.626 × 10-34-34 J·sec J·sec (Planks Constant)

http://phet.colorado.edu/new/simulations/sims.php?sim=Microwaveshttp://phet.colorado.edu/new/simulations/sims.php?sim=Radio_Waves_and_Electromagnetic_Fields

http://phet.colorado.edu/new/simulations/sims.php?sim=Color_Vision Simulation – mixing colors of light (what people see)

ExcitedExcitedGroundGround

Green & Yellow are the Green & Yellow are the only wavelengths that only wavelengths that are reflected.are reflected.

Filters

(Only Specific Wavelengths)

Every substance is unique

ExcitedExcitedGroundGround

Slowing down and changing the direction of lightSlowing down and changing the direction of light

Degree of Scattering

Slowing down and changing the direction of lightSlowing down and changing the direction of light

Degree of Scattering

Selective Scattering

Why…

Is the sky blue?Is the sky blue? Are clouds white/gray?Are clouds white/gray?

Is the ocean blue/green?Is the ocean blue/green? Are sunsets red/golden?Are sunsets red/golden?

I need some new/better PPT slides to I need some new/better PPT slides to explain why…explain why…

HOMEWORK: Designing new PowerPoint SlidesDesigning new PowerPoint Slides

Chose One:

blue-sky, white clouds, blue/green oceans, red sunsets

Include:1- How sunlight is a combination of all wavelengths (colors) of light

2- Which EM wavelengths/frequencies are involved (how)

3- How light is absorbed, reflected, scattered, etc.

4- What is occurring at the atomic level (Absorption & Emission)

Chapters 27 & 28 – Sections 27.4, 27.5, 28.3, 28.7 – 28.10

On the On the computercomputer OR OR hand drawnhand drawn

Electric charges vibrate in a variety of directions, thus creating an electromagnetic wave which vibrates in a variety of directions.

Unpolarized Light - waves vibrating in more than one plane

Polarized light - waves vibrating in a single plane.

UnpolarizedUnpolarized UnpolarizedUnpolarizedUnpolarizedUnpolarized

PolarizedPolarized

Polarization – process of transforming unpolarized light into polarized light. (Filter)

Using two polarization filters

Polarization axis aligned

Polarization axis perpendicular

http://micro.magnet.fsu.edu/primer/java/scienceopticsu/polarizedlight/filters/index.html Two Polarization filter - simulation

Polarization by reflection

Glare from the RoadGlare from the Road Removing the GlareRemoving the Glare

QuestionQuestion

Consider the three pairs of sunglasses below. Identify the pair of glasses is capable of eliminating the glare resulting from sunlight reflecting off the calm waters of a lake? _________ (The polarization axes are shown by the straight lines.)

3-D 3-D GlassesGlasses

Incident RayIncident Ray - the ray of light approaching the mirror

Reflected Ray - the ray of light which leaves the mirror

The Normal - an imaginary line perpendicular to mirror

Angle of IncidenceAngle of Incidence - the angle between the incident ray and the normal

Angle of Reflection - the angle between the reflected ray and the normal The law of reflection - when a ray of light reflects off a surface

the angle of incidence is equal to the angle of reflection

N

QuestionQuestion

- 1. Consider the diagram above. Which one of the angles (A, B, C, or D) is the angle of incidence? ______

- 2. Which one of the angles is the angle of reflection? ______

QuestionQuestion

A ray of light is incident towards a plane mirror at an angle of 30-degrees with the mirror surface. What will be the angle of reflection?

Reflection off of different types of surfaces

Specular reflection - Reflection off of smooth surfaces such as mirrors or a calm body of water

Diffuse reflection - Reflection off of rough surfaces such as clothing, paper, and the asphalt roadway

Scatters Light Scatters Light in all directionsin all directions

Rough Surface: Wet vs Dry

The law of reflection - the angle of incidence is equal to the angle of reflection (when a ray of light reflects off a surface).

Reflection off different types of surfaces

What if the Blue floor had a What if the Blue floor had a rougherrougher texture? texture?

Since sound waves travel at about 340 m/s at room temperature, it will take approximately 0.1 s for a sound to travel the length of a 17 meter17 meter room and back, thus causing a reverberation

Echoes - when a reflected sound wave reaches the ear more than 0.1 seconds0.1 seconds after the original sound wave was heard.

Reverberations - the prolonging of a sound. The reception of multiple reflections off of walls and ceilings within (less than) 0.1 0.1 secondsseconds of each other

Reflection of waves --- More than just light

> 17 m> 17 m

Reflection of waves --- More than just light

RadarRadar

Rough walls tend to diffuse sound, reflecting it in a variety of directions. This allows a spectator to perceive sounds from every part of the room, making it seem lively and full.

Smooth walls direct sound waves in a specific direction.

Reflection of waves --- More than just light

Focusing Focusing waveswaves

Boundary - When one medium ends, another medium begins; and the behavior of a wave at that boundary is described as its boundary behavior.

Change of medium at the boundaryChange of medium at the boundary

Slows DownSlows Down Speeds UpSpeeds Up

The speed of a wave is The speed of a wave is determined by the mediumdetermined by the medium

The boundary behavior of waves - summarized

1- the wave speed is always greatest in the least dense medium 2- the wavelength is always greatest in the least dense medium3- the frequency of a wave is not altered by crossing a boundary

FasterFaster SlowerSlower FasterFasterSlowerSlower

Greater Greater λλ Greater Greater λλSmaller Smaller λλ Smaller Smaller λλ

Frequency does Frequency does notnot change change Frequency does Frequency does notnot change change

QuestionQuestion

A pulse in a more dense medium is traveling towards the boundary with a less dense medium.

1. The speed of the pulse in the less dense medium will be

_______ (greater than, less than, the same as)(greater than, less than, the same as) the speed of the incident pulse coming from the more dense medium.

2. The wavelength of the pulse in the less dense medium will be _______ (greater than, less than, the same as)(greater than, less than, the same as) the wavelength of the incident pulse coming from the more dense medium.

3. The frequency of the pulse in the less dense medium will be _______ (greater than, less than, the same as)(greater than, less than, the same as) the frequency of the incident pulse coming from the more dense medium.

Does the Does the straw break?straw break?

Refraction

Minuscule amount of time before release

Sp

eed o

f Lig

ht

Sp

eed o

f Lig

ht

Sp

eed o

f Lig

ht

Sp

eed o

f Lig

ht

Minuscule amount of time before release

Sp

eed o

f Lig

ht

Sp

eed o

f Lig

ht

Start FinishPhotonPhoton

PhotonPhoton

PhotonPhoton Dense

Denser

Densest

Higher Density = Slower wave speed

Refraction – Tractor Model

Reflection - change in direction of waves when they bounce off a barrier.

Refraction change in the direction (bending) of waves as they cross from one medium to another.

-Caused by a change in speed and wavelength of the waves

http://www.phy.ntnu.edu.tw/ntnujava/index.php?topic=16 Refraction – wave fronts

Refraction (bending) only occurs at the boundary. Refraction (bending) only occurs at the boundary.

AirAir Less Dense Less Dense FasterFaster

Glass Glass More Dense More Dense SlowerSlower

The boundary behavior of waves - summarized

1- the wave speed is always greatest in the least dense medium 2- the wavelength is always greatest in the least dense medium3- the frequency of a wave is not altered by crossing a boundary

FasterFaster SlowerSlower FasterFasterSlowerSlower

Greater Greater λλ Greater Greater λλSmaller Smaller λλ Smaller Smaller λλ

Frequency does Frequency does notnot change change Frequency does Frequency does notnot change change

http://micro.magnet.fsu.edu/primer/java/refraction/refractionangles/index.html

Refraction Index simulator - including refraction of individual wavelengths

More Dense = More Dense = greater angle greater angle

material n material n

Vacuum 1 Crown Glass 1.52

Air 1.0003 Salt 1.54

Water 1.33 Asphalt 1.635

Ethyl Alcohol 1.36 Heavy Flint Glass 1.65

Fused Quartz 1.4585 Diamond 2.42

Whale Oil 1.460 Lead 2.6

The amount by which light The amount by which light slowsslows (and therefore bends) in a (and therefore bends) in a given material is described by the given material is described by the index of refractionindex of refraction

n = c/v8

8

109.2

103

x

xn

8

8

102.2

103

x

xn 8

8

101

103

x

xn

Dense Dense SlowSlow

Denser Denser SlowerSlower

Densest Densest SlowestSlowest

http://www.ps.missouri.edu/rickspage/refract/refraction.html Refraction Index, Total Internal Reflection, and Critical Angle Simulation

More dense More dense More bendingMore bending

Total Internal Reflection (TIR) - when the angle of incidence is greater than the critical angle, no refraction occurs.

--Depends upon the Angle of Incidence & the medium density

The Sparkle of Diamonds – All incoming light can only exit the diamond out of the top of the gem

Refractive IndexRefractive Index

Critical AngleCritical Angle

Reflection at the Critical Angle (Total Internal Reflection)

http://www.olympusmicro.com/primer/java/refraction/criticalangle/index.html Critical Angle of Reflection Simulation

Critical Angle - The largest angle of incidence for which refraction can still occur.

The angle of incidence yields an angle of refraction of 90-degrees.

For any angle of incidence greater than the critical angle, light will undergo total internal reflection (TIR).

RefractionRefraction

Critical AngleCritical Angle

Total Internal Total Internal ReflectionReflection

Dispersion - the separation of visible light into its different colors

http://micro.magnet.fsu.edu/primer/java/refraction/refractionangles/index.html Refraction simulator including individual wave lengths

Drop of Drop of waterwater

How are How are raraiinnbboowwss formed? formed?

Prism

Rainbows – Refraction, Dispersion, ReflectionBending of light Color Separation Direction Change Bending of light Color Separation Direction Change

1234 5 6 7

-Incident white light contains all wavelengthsall wavelengths     -Some of the light is reflectedreflected -The rest of the light is refractedrefracted    -Light splits (dispersion)(dispersion) into component colors    -ReflectedReflected at rear of raindrop (TIR – Total internal Reflection)    -RefractedRefracted again as it leaves raindrop -Colors are further disperseddispersed

White lightWhite light

AirAir HH22OO

Rainbows – Dependant on the angles (4040 - 4242°)

Greater angle of incidence = greater angle of refractionGreater angle of incidence = greater angle of refraction

http://www.olympusmicro.com/primer/java/refraction/fishtank/index.html

Diffraction - a change in direction of waves as they pass through an opening or around an obstacle in their path. (not across a boundary/medium change)

RefractionRefraction DiffractionDiffraction

BoundaryBoundary

OpeningOpening

Diffraction - a change in direction of waves as they pass through an opening or around an obstacle in their path. (not across a boundary/medium change)

Reflection - change in direction of waves when they bouncebounce off a barrieroff a barrier. (Also total interior reflection - TIR)

Refraction - change in the direction of waves as they pass from one medium to anotherone medium to another..

Diffraction - change in direction of waves as they pass pass through an openingthrough an opening or around an obstaclearound an obstacle in their path.

InterferenceInterference

Constructive & Destructive Wave Interference

Constructive interference occurs wherever a thick line meets a thick line or a thin line meets a thin line; this type of interference results in the formation of an antinode. Destructive interference occurs wherever a thick line meets a thin line; this type of interference results in the formation of a node.. `