- what are waves? waves and energy a wave is a disturbance that transfers energy from place to...

- What Are Waves? Waves and Energy A wave is a disturbance that transfers energy from place to place. Waves travel through water (or medium, but they do not carry the water (or the duck) (the object or medium) with them. The material through which a wave travels is through a medium. Gases (air), solids, and liquids all act as mediums.

How do Waves Transfer Energy? Mechanical waves, not electromagnetic waves, travel through a medium. Sound waves are mechanical waves. Waves travel through a medium, but they dont carry the medium with them. For instance, when the wave passes, the duck and the water return to where they started. Think of yourself on a raft. If you had not way to propel the raft (oars); youd remain in the same spot. Electromagnetic waves do not require a medium

Using what you know, complete the Venn Diagram comparing Mechanical Waves and Electromagnetic Waves Mechanical WavesElectromagnetic Waves

What causes waves? Vibration a repeated back-and-forth or up-and-down motion. Mechanical waves are produced when a source of energy causes a medium to vibrate. Energy is always required to make a wave.

Types of Waves Transverse (across) moves at a right angle to the source of the energy. The highest point is called the crest The lowest point is called the trough Exactly in between the high and the low point is known as its resting point. Amplitude is the maximum distance that the particles of the medium carrying the wave move away from their rest positions. It is the amount of energy a sound wave carries. Wavelength the distance between two correspoinding parts of a wave. Frequency The number of complete waves that pass a given point in a certain amount of time. Measured in Hertz

- What Are Waves? Transverse Waves Waves that move through the medium at right angles to the direction in which the waves travel are called transverse waves.

- What Are Waves? Longitudinal Waves Longitudinal waves move the medium parallel to the direction in which the waves travel. Sound is carried through longitudinal waves.

All Waves have amplitude, wavelength and frequency Amplitude is the maximum distance that the particles of the medium carrying the wave move away from their rest positions. It is the amount of energy a sound wave carries. Wavelength the distance between two correspoinding parts of a wave. Frequency The umber of complete waves that pass a given point in a certain amount of time. Measured in Hertz (Hz). An example of Hertz is : If two waves pass you every second, then the frequency of the wave is 2 per second, or 2Hz.

- Properties of Waves Amplitude, Wavelength, and Frequency The basic properties of all waves are amplitude, wavelength, and frequency. amplitude

What is happening to this wave? The energy is increasing because the frequency is increasing. As frequency increases, pitch gets higher. Below is an example of frequency increasing.

Waves Quiz Which set of waves is longitudinal? Type M for top, A for bottom. Which set of waves is transverse? Type M for top, A for bottom. Where is the crest on the top wave? Where is compression occurring? Where is rarefaction occurring? Where is the trough? Where is the amplitude? Where is the waves resting point? Which wave represents wave lengths?

- Properties of Waves Wave Quiz Use your responders to answer the questions at the front of the room. Do not press select until you have typed in all 9 answers. U P L I T D

Calculating Frequency The speed of a wave on a rope is 50 cm/s and its wavelength is 10 cm. What is the waves frequency? Plan and Solve What quantity are you trying to calculate? The frequency of a wave = __ Hz What formula contains the given quantities and the unknown quantity? Frequency = Speed/Wavelength Perform the calculation. Frequency = Speed/Wavelength = 50 cm/s/10 cm Frequency = 5/s = 5 Hz - Properties of Waves

Calculating Frequency The speed of a wave on a rope is 50 cm/s and its wavelength is 10 cm. What is the waves frequency? Look Back and Check Does your answer make sense? The wave speed is 50 cm per second. Because the distance from crest to crest is 10 cm, five crests will pass a point every second. - Properties of Waves

Interactions of Waves Reflection, Refraction, Diffraction Reflection When a wave hits a surface through which it cant pass. This is called a reflection. The law of reflection states that the angle of incidence equals the angle of reflection. Refraction The bending of waves due to a change in speed. When a wave enters a new medium at an angle, one side of the wave changes speed before the other side, causing the wave to bend. Bending occurs because the two sides of the wave travel at different speeds. Diffraction When a wave moves around a barrier or through an opening in a barrier and it spreads out.

When waves hit a surface, they move 3 ways, through reflection, refraction and diffraction Reflection The Law of Reflection: The angle of incidence equals the angle of reflection. All types of waves are reflected. You can see your face in a mirror because light waves from your face are reflected back from the mirrors shiny surface. Refraction When a wave enters a new medium at an angle, one side of the wave changes speed before the other side, causing the wave to bend. The bending of waves due to a change in speed is refraction.

- Interactions of Waves The Third Way: Diffraction When a wave moves around a barrier or through an opening in a barrier, it bends and spreads out.

- Interactions of Waves Interference the interaction between waves that meet. The interference that occurs when waves combine to make a wave with a larger amplitude is called constructive interference. The interference that occurs when waves combine to make a wave with a smaller amplitude is called destructive interference. More about diffraction:

Standing Wave If you tie a rope to a doorknob and continuously shake the free end, waves will come back (reflect). It can make the wave look like its standing still. See next slide

- Interactions of Waves Standing Waves If the incoming wave and a reflected wave have just the right frequency, they produce a combined wave that appears to be standing still.

QuestionAnswer Answer the Questions Below Answer the questions below: How are waves reflected? What is refraction? When does diffraction occur? What is a standing wave? - Interactions of Waves

- Seismic Waves Types of Seismic Waves Seismic waves include P waves, S waves, and surface waves.

Motion of a Tsunami This graph shows the rate at which a tsunami moves across the Pacific Ocean. Use the data plotted on the graph to answer the following questions. - Seismic Waves

Motion of a Tsunami Reading Graphs: What two variables are plotted on the graph? - Seismic Waves

Types of Seismic Waves Earthquakes that occur underwater, like the one off the coast of Chile in 1960, can produce huge surface waves on the ocean called tsunamis.

Waves Longitudinal All have frequency, amplitude and wavelength can be Transverse can be contain CrestsRarefactionsTroughsCompressions

Table of Contents The Nature of Sound Properties of Sound Music How You Hear Sound Using Sound Sound Video: http://science.howstuffworks.com/29406- assignment-discovery-electromagnetic-waves- and-light-video.htm Play Discovery Sound Video Here

- The Nature of Sound Sound Waves Sound is a disturbance (vibration) that travels through a medium as a longitudinal (move the medium parallel to the source) wave. As a gong vibrates, it creates sound waves that travel through the air.

How Sound Travels Sounds travel through the states of matter (medium), known as gases (air), solids, and liquids.

- The Nature of Sound Interactions of Sound Waves Sound waves reflect off objects, diffract through narrow openings and around barriers, and interfere with each other. Echo!

- The Nature of Sound The Speed of Sound The speed of sound depends on the elasticity, density, and temperature of the medium the sound travels through. Which type of medium does sound travel the fastest according to the chart? The closer together molecules are, the faster sound is able to travel. You can devise this from the chart.

Temperature and the Speed of Sound The speed of sound in dry air changes as the temperature changes. The graph shows data for the speed of sound in air at temperatures from 10C to 20C. - The Nature of Sound

Temperature and the Speed of Sound Reading Graphs: What is the speed of sound in air at 10C? The speed at 10C is 325 m/s. - The Nature of Sound

Temperature and the Speed of Sound Interpreting Data: Does the speed of sound increase or decrease as temperature increases? The speed of sound increases as air temperature increases. - The Nature of Sound

Temperature and the Speed of Sound Reading Graphs: What is the speed of sound in air at 10C? The speed at 10C is 325 m/s. - The Nature of Sound

Temperature and the Speed of Sound Predicting: What might be the speed of sound at 30C? At 30C, the speed of sound might be 349 m/s. - The Nature of Sound

Sound A disturbance that travels through a medium as a longitudinal wave. Carry energy through a medium without moving the particles of the medium along. Each particle of the medium vibrates as the disturbance passes. When the disturbance reaches your ears, it causes your eardrums to vibrate, and you hear sound which is interpreted by your brain.

Graphic Organizer Longitudinal waves Sound has properties Intensity DensityPitch travels as speed depends onis heard as Frequency ElasticityTemperatureLoudness

Interactions of Sound waves Sound waves can reflect when they hit a surface, and this may cause an echo Sound can diffract through openings Sound can interfere with each other constructively (add to the sound waves) or destructively (cancel each other out)

The Speed of Sound At room temperature, sound travels at about 343 m/s, which is much faster than most jets! Sound travels at different speeds through different mediums and at different temperatures. Speed of sound depends on temperature, elasticity and the density of the medium.

- The Nature of Sound Elasticity Elasticity is the ability of a material to bounce back after being disturbed. You can model elasticity by representing the particles in a medium as being held together by springs. The more elasticity, the faster sound travels.

- The Nature of Sound Density Density is how much mass there is in a give volume. The volumes of the cubes are the same, but the brass has more mass. The greater the density, the less sound gets through.

- Properties of Sound Loudness The loudness of different sounds is compared using a unit called the decibel (dB). Depends on two factors: the amount of energy it takes to make the sound and the distance from the source of the sound. Intensity is the amount of energy a sound wave carries per second through a unit area.

- Properties of Sound Pitch The pitch of a sound that you hear depends on the frequency of the sound wave. The higher the pitch, the greater the Frequency of the wave.

- Properties of Sound Changing Pitch When you sing, you change pitch using your vocal cords. Your vocal cords are located in your voice box, or larynx.

Examples of what pitch looks like Medium PitchHigh Pitch (high frequency) Lowest Pitch (low wave frequency) Lower Pitch but not nearly as low as the wave to the left.

- Properties of Sound The Doppler Effect The change in frequency of a wave as its source moves in relation to an observer is called the Doppler effect. When a sound source moves, the frequency of the waves changes because the motion of the source adds to the motion of the waves. http://www.metacafe.com/watch/961110/doppler_effect/ http://www.youtube.com/watch?v=XDqS3yOwYWc

- Properties of Sound The Doppler Effect When the plane travels almost as fast as the speed of sound, the sound waves pile up in front of the plane. This pile up is the sound barrier. http://www.youtube.com/watch?v=eo_owZ2UK7E http://www.youtube.com/watch?v=eo_owZ2UK7E

- Music Sound Quality The sound quality of musical instruments results from blending a fundamental tone with its overtones. Resonance also plays a role in sound quality.

- Music Groups of Musical Instruments There are three basic groups of musical instruments: stringed instruments, wind instruments, and percussion instruments.

Acoustics and Reverberation Acoustics the study of how sounds interact with each other and the environment. Acoustics matter in our classroom because the more sounds reverberate in the classroom, the less youll be able to hear what I say. Can you think of other places acoustics matter?

- How You Hear Sound The Human Ear The outer ear funnels sound waves, the middle ear transmits the waves inward, and the inner ear transforms sound waves into a form that travels to your brain.

Hearing Loss Can be caused by: Heredity Injury Infection Exposure to loud sounds Aging

- Using Sound Echolocation Some animals, including bats and dolphins, use echolocation to navigate and to find food.

- Using Sound Sonar A sonar device sends out ultrasound waves and then detects the reflected waves.

Light and Color Reflection and Mirrors Refraction and Lenses Seeing Light Using Light Video: http://science.howstuffworks.com/29406- assignment-discovery-electromagnetic-waves- and-light-video.htm

- Light and Color When Light Strikes an Object When light strikes an object, the light can be reflected, transmitted, or absorbed. Explain difference between the three.

Transparent Transmits most of the light that strikes it. The light passes right through without being scattered. Clear glass, water and air are examples. Translucent Scatters light as it passes through. Frosted glass, and wax paper are examples. Opaque Reflects or absorbs all of the light that strikes it. Light cannot pass through them. Wood, metal, and tightly woven fabrics are opaque.

Light Absorption and Reflection Give objects their colors.

- Light and Color The Color of Objects The color of an opaque object is the color of the light it reflects.

- Light and Color The Color of Objects The color of a transparent or translucent object is the color of the light it transmits.

- Light and Color Combining Colors As pigments are added together, fewer colors of light are reflected and more are absorbed.

- Reflection and Mirrors Reflection of Light Rays The two ways in which a surface can reflect light are regular reflection and diffuse reflection.

- Reflection and Mirrors Concave Mirrors A mirror with a surface that curves inward like the inside of a bowl is a concave mirror.

- Reflection and Mirrors Concave Mirrors Ray diagrams show where an image forms and the size of the image. The steps below show how to draw a ray diagram.

- Reflection and Mirrors Concave Mirrors Concave mirrors can form either virtual images or real images.

- Reflection and Mirrors Convex Mirrors A mirror with a surface that curves outward is called a convex mirror.

Complete the diagram below Concave MirrorConvex Mirror - Reflection and Mirrors

- Refraction and Lenses Refraction of Light When light rays enter a medium at an angle, the change in speed causes the rays to bend or change direction.

Refraction When sunlight passes through a prism, rays are bent, or refracted Prism: separates the colors of light (dispersion) rainbows are caused by refraction in the atmosphere

Bending Light The index of refraction of a medium is a measure of how much light bends as it travels from air into the medium. The table shows the index of refraction of some common mediums. - Refraction and Lenses

Bending Light Interpreting Data: Which medium causes the greatest change in the direction of a light ray? Diamond causes the greatest change in the direction of a light ray traveling from air. - Refraction and Lenses

Bending Light Interpreting Data: According to the table, which tends to bend light more: solids or liquids? According to the graph, most solids bend light more than liquids do (quartz is an exception). - Refraction and Lenses

Bending Light Predicting: Would you expect light to bend if it entered corn oil at an angle after traveling through glycerol? Explain. You would not expect light to bend if it entered corn oil at an angle after traveling through glycerol, because corn oil and glycerol have the same value for the index of refraction. - Refraction and Lenses

When light passes through water Waves are refracted and bends so it looks like objects you put in the water bends because light slows down. http://www.bing.com/ videos/search?q=stev e+spangler+refractio n&FORM=VIRE1#vie w=detail&mid=1C66 ADFAEEB1970FCF11 1C66ADFAEEB1970 FCF11 http://www.bing.com/ videos/search?q=stev e+spangler+refractio n&FORM=VIRE1#vie w=detail&mid=1C66 ADFAEEB1970FCF11 1C66ADFAEEB1970 FCF11 WATER

- Refraction and Lenses Lenses A lens is a curved piece of glass or other transparent material.

- Refraction and Lenses Lenses An objects position relative to the focal point determines whether a convex lens forms a real image or a virtual image.

- Refraction and Lenses Lenses A concave lens can produce only virtual images because parallel light rays passing through the lens never meet.

- Seeing LightVision Know the parts of the eye and their functions. http://www.youtube.com/watch?v=gvozcv8pS3c http://www.youtube.com/watch?v=gvozcv8pS3c Pages 631 and 632 of you text draw the eyeball, the functions of what you have labeled, and draw a schematic of what happens when light hits your eye (p 630) Retina is like a screen on a camera. The part of the eye that absorbs visible light waves with the highest frequencies is: blue cones.

- Seeing Light What happens when light enters the eye and passes through the lens? The light undergoes REFRACTION and forms an image on the retina.

How You See Objects Light enters the eye. Light focuses on the retina. An image forms. Rods and cones send signals to the brain. - Seeing Light How do we see?

- Using Light Optical Instruments A telescope forms enlarged images of distant objects. Telescopes use lenses or mirrors to collect and focus light from distant objects.

- Using Light Optical Instruments A microscope uses a combination of lenses to produce and magnify an image.

- Using Light Optical Instruments The lens of the camera focuses light to form a real, upside-down image on film in the back of the camera.

- Using Light Lasers Laser light consists of light waves that all have the same wavelength, or color. The waves are coherent, or in step.

- Using Light Optical Fibers The floodlight in the swimming pool gives off light rays that travel to the surface. If the angle of incidence is great enough, a light ray is completely reflected back into the water. This complete reflection of light by the inside surface of a medium is called total internal reflection.

- Using Light Optical Fibers Optical fibers can carry a laser beam for long distances because the beam stays totally inside the fiber as it travels.

Graphic Organizer Virtual Type of Mirror Effect on Light Rays Type of Image Type of lens Effect on Light Rays Type of Image PlaneRegular reflection Real or virtual ConvexSpread out Convex Virtual ConcaveConverge Virtual ConvergeReal or virtual ConcaveSpread out

Table of Contents The Nature of Electromagnetic Waves Waves of the Electromagnetic Spectrum Producing Visible Light Wireless Communication

The Nature of Electromagnetic Waves Electromagnetic Waves Believe it or not, you are being showered all the time, not by rain but by waves.

The Nature of Electromagnetic Waves What Is an Electromagnetic Wave? An electromagnetic wave consists of vibrating electric and magnetic fields that move through space at the speed of light.

The Nature of Electromagnetic Waves Models of Electromagnetic Waves Many properties of electromagnetic waves can be explained by a wave model. Only some light waves pass through a polarizing filter. The light that passes through vibrates in only one direction and is called polarized light.

Waves of the Electromagnetic Spectrum What Is the Electromagnetic Spectrum? The electromagnetic spectrum is the complete range of electromagnetic waves placed in order of increasing frequency. The part of the eye that absorbs visible light waves with the highest frequencies are: blue cones.

Scientific Notation Frequencies of waves often are written in scientific notation. A number in scientific notation consists of a number between 1 and 10 that is multiplied by a power of 10. To write 150,000 Hz in scientific notation, move the decimal point left to make a number between 1 and 10: In this case, the number is 1.5. The power of 10 is the number of spaces you moved the decimal point. In this case, it moved 5 places: 150,000 Hz = 1.5 X 10 5 Hz Waves of the Electromagnetic Spectrum

Scientific Notation Practice Problem A radio wave has a frequency of 5,000,000 Hz. Write this number in scientific notation. 5.0 X 10 6 Hz Waves of the Electromagnetic Spectrum

Graphic Organizer Magnetic fields Electromagnetic waves consist of travel at the speed of have different Electric fieldsWavelengths Light Frequencies

Electromagnetic Waves Electromagnetic waves are all around youin your home, your neighborhood, and your town. Waves of the Electromagnetic Spectrum

The Electromagnetic Spectrum Q. Which electromagnetic waves have the shortest wavelength? A. Gamma rays have the shortest wavelength. Q. Which electromagnetic waves have the lowest frequency? A. Radio waves have the lowest frequency. Waves of the Electromagnetic Spectrum

Producing Visible Light Incandescent Lights An incandescent light is a light bulb that glows when a filament inside it gets white hot.

Producing Visible Light Neon Lights A neon light is a sealed glass tube that contains neon gas.

Feature Comparing and Contrasting Glass Ordinary Light Bulb Tungsten- Halogen FluorescentVaporNeon Bulb Material Hot/Cool Makeup Efficiency Quartz Glass HotVery HotCool Tungsten filament and nitrogen gas and argon gas inside Has tungsten filament and a halogen gas inside A gas and a powder coating inside Has neon or argon gas and solid sodium or mercury inside Has neon gas inside Not efficient More efficient than ordinary bulb Very efficient Producing Visible Light Glass Cool Very efficient

Wireless Communication Radio and Television In AM transmissions, the amplitude of a radio wave is changed. In FM transmissions, the frequency is changed.

Comparing Frequencies The table shows the ranges of radio broadcast frequencies used for AM radio, UHF television, FM radio, and VHF television. Wireless Communication

Comparing Frequencies Interpreting Data: In the table, what units of measurement are used for frequency? Kilohertz (kHz) and megahertz (MHz) Wireless Communication

Comparing Frequencies Interpreting Data: Which type of broadcast shown in the table uses the highest frequency radio waves? Which uses the lowest frequency waves? UHF television uses the highest frequency radio waves, and AM radio broadcast uses the lowest frequency radio waves. Wireless Communication

Comparing Frequencies Calculating: Which type of broadcast uses waves with the shortest wavelength? UHF television uses waves with the highest frequency and therefore the shortest wavelength. Wireless Communication

Comparing Frequencies Inferring: A broadcast uses a frequency of 100 MHz. Can you tell from this data if it is a television or radio program? Explain. You cannot tell from this data if it is a television or radio program, because VHF television and FM radio both broadcast radio waves with a frequency of 100 MHz. Wireless Communication

Wireless Communication Cellular Phone System In the cellular phone system, cellular phones transmit and receive radio waves that travel to the nearest tower.

Wireless Communication Communication Satellites In the Global Positioning System (GPS), signals from four satellites are used to pinpoint a location on Earth.

What You Know What You Learned Using Prior Knowledge 1.Cellular phones dont use wires. 2.Radio and television signals travel through the air. 1.The signals for radio and television programs are carried by radio waves. 2.The signals can be transmitted by changing either the amplitude or the frequency of the radio waves. 3.Cellular phones transmit and receive signals using microwaves. Wireless Communication

Graphic Organizer Magnetic fields Electromagnetic waves consist of travel at the speed of have different Electric fieldsWavelengths Light Frequencies

- what are waves? waves and energy a wave is a disturbance that transfers energy from place to...

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