2 Sound Sound travels from one place to another as sound waves A sound wave is alongitudinal wave that can only travel through matter (Solids, liquids, gases)Vibrationsproduce sound waves bymoving molecules in air.
3 How does the ear work? Sound waves are sent. The outer ear “catches the sound waves”.The middle ear takes the sound waves and “vibrates” the eardrum.The inner ear sends the messages to the brain.Middle EarOuter EarSound WavesInner EarThe brain puts it together and hooray! You hear your favorite song on the radio.
8 Like other waves, a sound wave can be described by its: WavelengthFrequencyWavelength:distance from center ofrarefaction to next rarefaction (vice versa)Frequency:The # of wavelengths that passa given point in one secondThe unit forfrequency isHertz (Hz)
9 Speeds of Sound Waves A sound wave’s speed increases when the material’s density increases.Solids and liquids are dense than gases.moreSound waves usually travel faster insolidsthan in orliquidsgases.The speed of sound waves increase as the temperatureincreases.
11 If sound travels faster in water than in air…then why is it harder to talk to someone underwater? Sound couples poorly moving from air to water.Your lungs provide the burst of air when talking underwater.In order for someone underwater to hear you, the sound waves have to go from the air in your mouth to the water surrounding you.This causes the sound waves to get reflected where the air meets the water.
12 Pitch Pitch: how high or low a sound seems A sound wave with a higher frequency has a pitch.higherA sound wave with a lower frequency has a pitch.lower
17 Some animals use to locate their prey and detect objects. Animals such as dolphins and bats send out and when those waves hitan object it bounces backecholocationsound wavesvibrations.
18 Sound Travels Through Matter LiquidsSome sounds that we hear travel through water.Sound waves travel faster through water than through the air.Sonar is the way to use sounds to locate objects under water.GasesMost of the sounds we hear travel through gases, such as air.Sound waves travel slowly through the air.For example: Sound from a bell, a horn, or an alarm clock travels through the air.SolidsSome sounds that we hear travel through solids.Sound waves travel very fast through solids.For example: When you hit a drum, it vibrates, then the sound travels through the air, to your ears.
20 UltrasoundUltrasound scanners convert high-frequency sound waves to images of internal body parts.The sound waves reflect from structures within the body.The scanner analyzed the reflected waves and produces images called sonograms.
22 Breaking the Sound Barrier When the vehicle (jet) exceeds the speed at which sound travels.The cone of vapor you see is the existing moisture in the air being condensed by pressure wave created by the vehicle creating a cloud.
24 Light Light is a type of wave called an electromagnetic wave.Light does not need a to travel through.A medium isLight can travel through aAn example of a vacuum is themediuma material through whicha wave travels.vacuum.space between Earth and the Sun.
25 Light travels at different speeds through different mediums
26 Electromagnetic Spectrum The electromagnetic spectrum includesWavelengths are measured ina range of electromagnetic waves.nanometers.Wavelength is 400nmWavelength is 700nm
27 A is something that emits (gives off) heat. Examples of light sources include:A light ray is alight sourceburning candle, sun, light bulbnarrow beam of light thattravels in a straight line.Laser
28 We see things because they A is the process of light striking an object and bouncing off.reflectionWe see things because theylight intoreflectour eyes.Homework
29 Transparent: almost all light passes through object Depending on how materials interact with light, they are classified as:transparent, translucent, or opaqueTransparent: almost all light passes through objectTranslucent:most light passes through & blurry image formsOpaque:no light passes through it
31 When light waves interact with matter they can be: Transmitted2. Absorbed3. Reflectedlight waves travel through a material(transparent object)light waves are converted to other forms; translucent objectlight waves bounce of surface of material(opaque object)
32 Law of ReflectionThe angle of incidence is always equal to the angle of reflection.NormalIncident rayReflected rayAngle of incidenceAngle of reflectionMirror
33 Scattering occurs when light waves HAVE YOU EVER SEEN DUST PARTICLES FLOATING IN THE AIR WHEN A BEAM OF SUNLIGHT SHINES THROUGH A WINDOW?This is an example ofscattering.Scattering occurs when light wavestravelling in one direction are made to travel in many directions.
34 RefractionLight waves change when they travel from one material to another.The bending of a wave as it moves from one material to another is calledThis is due to a change indirectionrefraction.speed.
35 LightLight is slower when passing throughdense materials.
36 Retina Cones Rods 6 million 120 million Response to light waves with different wavelengths allow you to see different colors.3 types – each detecting a different wavelength.In some people, not all 3 function properly = color blindness/color deficiency.Rods120 millionAllow you to see in dim lightBlack and white signals – does not allow you to see color.
37 People with color deficiency cannot see a number in this picture!
40 Regular Reflection Light waves reflect off a mirrorlike surface.The reflects light rays traveling in the same direction at the same angle.smooth surface
41 Diffuse ReflectionWhen a surface is not smooth the reflected angle travelsin many differentdirections.
42 MirrorsA is any reflecting surface that forms an image by regular reflection.mirrorPlane Mirror:Convex Mirror:Concave Mirror:Flat surfaceSame image, just reversed left to rightCurved InwardObjects can appear upside down or right-side upCurved outwardObjects are smaller and right-side up
43 Cosmetic mirrors are often concave mirrors.Image becomesmagnified.Convex mirrors are often used forsafety purposes.
44 Lens A lens is a transparent object with at least one curved side that causes light to change directionConvex LensesCurved outwardThicker in the middleObjects appear larger
45 Glasses for nearsightedness (can’t see far) Concave LensCurved inwardThicker at the sidesObject is shown smallerGlasses for nearsightedness (can’t see far)
46 How do objects get their color? Objects light.Colors depend on the of the light waves it reflects.reflectwavelengthsThe rose looks red because all the other wavelengths are absorbed but red is reflected.
47 combination of all light waves. White light is acombination of all light waves.Neon lights emit different colors.(give off)The appearance of an object changes under different lights.