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Waves Review • Waves are created when a source of energy causes a medium to vibrate. • A wave is a disturbance that transfers energy from place to place. • The material through which a wave travels is called a medium. • Gases (such as air), liquids (such as water), and solids (such as ropes) all act as mediums. • Not all waves require a medium to carry them along. • Light from the sun, for example, can travel through empty space (vacuum). Light is an example of an

electromagnetic wave. • The types of waves Transverse Waves Waves that move the medium at right angles to the direction in which the

waves are traveling are called transverse waves. Transverse means “across.” Longitudinal (Compression) Waves

Longitudinal waves (lawn juh too duh nul) move the particles of the medium parallel to the direction in which the waves are traveling.

• The basic properties of waves are amplitude, wavelength, frequency, and speed. • Amplitude is the maximum distance the particles of the medium carrying the wave move away from their rest

positions. • The amplitude of a wave is a direct measure of its energy. • The amplitude of a transverse wave is the maximum distance the medium moves up or down from its rest

position. • The distance between two corresponding parts of a wave is its wavelength.

Review Questions

1. Waves are disturbances that transfer __________________.

2. The material through which a wave travels is called a(n) ____________________.

3. Label each part of the wave and identify what type

of wave is in the diagram above.

4. ____________________ occurs when a wave goes around the edge of a barrier.

5. The distance from one crest to another is the _____________________.

6. What type of wave would be transmitted through the rabbit spring toy if the wave

was moving parallel to the medium? _________________________

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Sound

• Sound is a disturbance (vibration) that travels through a medium as a longitudinal wave. • Sound requires a medium to travel through. • Sound cannot travel through a vacuum, but light can. • Sound travels slower than light. This is why you see lightning before you hear

thunder. • Sound travels at different speeds through different mediums. See table to right → • Sound disturbances move when particles bump into each other. • Higher temperatures will increase the speed of sound. • The closer the particles are together, the sooner they bump into each other.

Review Questions 7. Sound waves cannot travel through a ______________________. 8. Sound is caused by the ______________________ of particles. 9. The speed of light is _______________________than the speed of sound. 10. You hear thunder several seconds after you see lightning because light travels at a ____________________

speed than sound. 11. Sound travels fastest through _____________________________ materials. 12. Sound travels faster when the temperature is ______________________.

Electromagnetic Spectrum

• Are transverse waves that have some

electrical and some magnetic properties.

• Electromagnetic waves can transfer energy through a medium or in space.

• All electromagnetic waves travel at 300,000,000 m/sec in a vacuum.

• They change speeds in different mediums.

• Different electromagnetic waves have different wavelengths and frequencies.

• The shorter the wavelength, the more dangerous and higher the electromagnetic energy. • Gamma rays have the shortest wavelength. • Ultraviolet radiation (UV) is found in light from the sun. It causes sunburn and skin cancers. • Ozone in the stratosphere blocks out most of the UV radiation from the Sun. • Visible light is the only electromagnetic energy

we can see. • Infrared radiation produces heat energy.

Review Questions

13. Complete the table and draw an arrow that indicates the direction increasing frequency.

14. Electromagnetic waves can travel through a medium or a __________________.

15. Each type of electromagnetic energy has a different _____________________.

16. The only electromagnetic wave that we can see is _____________________.

17. Ozone blocks out __________________________.

Speed of sound in different mediums. Fastest Solid

Middle Liquid

Slowest Gas

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Light Energy

• To show how light travels and reflects or refracts, you can represent light waves as straight lines called rays. • When light rays enter a new medium at an angle, the change in speed causes them to bend, or change direction.

(Refraction) • Light waves travel as transverse waves. • When light strikes an object, the light can be reflected,

absorbed, or transmitted. • The color of an object is the color it reflects. • Different colors either absorb or reflect light. • A lens is a curved piece of glass or other transparent material

that is used to refract light. • A lens that is thicker in the center than at the edges is a

convex lens. • A lens that is thinner in the center than at the edges is a

concave lens.

• When a wave hits a surface through which it cannot pass, it bounces back. This is called reflection.

• The law of reflection states: The angle of reflection equals the angle of incidence.

• When a wave moves from one medium into another medium at an angle, it changes speed as it enters the second medium causing it to bend. This is known as refraction

• When a wave passes a barrier or moves through a hole in a barrier, it bends and spreads out. This is known as diffraction.

• When light comes into contact with a surface it cab be reflected,

transmitted or absorbed and converted into thermal energy.

Chapter 6 Properties of Light and SoundTransparency Master 205 Copyright © by Amsco School Publications, Inc.

Incoming light raysReflectedlight ray

Transmittedlight ray

Absorbed light ray(light energy is

transformed intoheat energy)

Figure 6.3-1. Depending on the type of surfaceit strikes, light may be reflected, absorbed, ortransmitted.

Chapter 6 Properties of Light and SoundTransparency Master 206 Copyright © by Amsco School Publications, Inc.

Pencil

Glass ofwater

Figure 6.3-2. The bending or refraction of lightrays as they pass from one medium to anothermakes the pencil look bent or broken.

Chapter 6 Properties of Light and SoundTransparency Master 207 Copyright © by Amsco School Publications, Inc.

Prism

RedOrangeYellowGreenBlueViolet

Dispersion

Refraction

White light

Figure 6.3-3. White light passing through aprism is refracted and dispersed, producing thevisible spectrum.

Chapter 6 Properties of Light and SoundTransparency Master 208 Copyright © by Amsco School Publications, Inc.

Light rayscome together

Light raysspread out

Lightrays

Lightrays

Convex lens Concave lens

Figure 6.3-4. The shape of a lensdetermines how it bends rays oflight.

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Review Questions

18. What causes the refraction light rays?

19. A __________________ is a curved piece of glass or other transparent substance that is used to refract light. 20. The ________________ is a measure of how much a ray of light bends when it passes from one medium into

another. 21. We see objects because the objects _________________ light. 22. A light colored, smooth surface will _______________________ light more than a dark, rough surface. 23. A black shirt will tend to __________________________ light energy 24. Clear glass will ___________________ light. 25. Label each diagram as refraction, diffraction, absorption or reflection

Label the wave below 1.__________________________ 2._________________________ 3._________________________ 4._________________________ 5. Label the waves shown below as a longitudinal (compressional) or transverse. Label the compression and rarefaction of the longitudinal wave. Chapter 6 Properties of Light and Sound

Transparency Master 211 Copyright © by Amsco School Publications, Inc.

Thinking and Analyzing

11.. Base your answers to the questions onthe diagram at the right and on yourknowledge of science. The diagram showshow a glass prism affects white light.(a) What happens to the white light as itpasses through the prism?(b) Which color of the visible spectrumis bent the most?(c) Explain why white light is bent whenit strikes the prism.

22.. Base your answers to the questions onthe diagrams below and on yourknowledge of science. The diagramsshow what happens to a light ray when itstrikes a surface.

(a) Which surface represents a mirror?(b) Describe what is happening to thelight ray in diagram C.(c) What type of energy transformation isoccurring in diagram B?

Prism

RedOrangeYellowGreenBlueViolet

White light

A B C

e.__________________ f.__________________

b.__________________

d.__________________

a.__________________

g.__________________

c.__________________

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1. Why is a sound wave considered a mechanical wave?

2. What is an echo?

3. Explain why you cannot hear a balloon pop inside of a vacuum.

4. Water waves bending around a dock is an example of _______________________.

5. The _______________________ of a wave is a measure of the energy it carries. 6. In a compressional wave in a coiled spring, a____ __________is where the coils are spread out. 7. A ________________ is a repeating disturbance that transfers energy through matter or space. 8. Waves bending because of a change in speed is called ________________. 9. The medium vibrates across to the direction the wave travels in a _____________. 10. When you squeeze the coils of a spring together, you cause a ________________. 11. The ________________ is the material through which a mechanical wave travels.

12. Which diagram represents a loud sound? Explain.

13. What type of wave is wave A? _____________________________________

14. Where is the highest and lowest frequencies? Where is the wavelength the longest? Label all the waves in the diagram below.

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15. Wave(A(carries(more(energy(than(wave(B.(Wave(B(has(a(smaller(____(than(wave(A.(((((((A)(rest(position(((B)(wavelength(((C)(amplitude(((D)(speed(

(16. The(energy(a(wave(carries(is(measured(by(its(____.(

A)(wavelength(((B)(frequency(((C)(amplitude(((D)(speed((

17. You(can(see(this(paper,(your(desk,(and(the(person(in(front(of(you(because(light(is(being(____.(A)(absorbed(((B)(refracted(((C)(diffracted(((D)(reflected(

(18. Sound(travels(in(a(____(wave.(

A)(transverse(((B)(longitudinal(((C)(surface(((D)(inverted((

19. The(speed(of(sound(in(____(is(greater(than(the(speed(of(sound(in(water.(A)(air(((B)(steel(((C)(cork(((D)(water(vapor((

20. The(unit(used(to(measure(frequency(is(the(____.(A)(newton(((B)(joule(((C)(decibel(((D)(hertz(

(21. Electromagnetic(waves(____.(

A)(are(compressional(waves(((B)(are(transverse(waves(((C)(must(have(a(medium(((D)(are(generated(by(static(electricity((

22. If(light(waves(change(speed(when(they(pass(from(one(medium(into(another,(the(light(will(be(____.(A)(diffused(((B)(reflected(((C)(refracted(((D)(separated(

(23. A(disturbance(that(transfers(energy(from(place(to(place(is(called(a(

A) wave.(((B)(medium.(((C)(vibration.(((D)(compression.((

24. The(material(through(which(a(wave(travels(is(called(a((((((A)vibration.(((B)(medium.(((C)(crest.(((D)(trough.((

25. Waves(are(created(when(a(source(of(energy(causes(a(medium(to((((((((((A()(move.(((B)(compress.(((C)(expand.(((D)(vibrate.((

26. Waves(are(classified(according(to(A) their(size.(((B)(their(shape.(((C)(how(they(move.(((D)(their(source.(

(27. Waves(that(move(the(particles(of(the(medium(parallel(to(the(direction(in(which(the(waves(are(traveling(are(called(

A) longitudinal(waves.(((B)(transverse(waves.(((C)(surface(waves.(((D)(combination(waves.((

28. The(maximum(distance(that(the(particles(of(a(medium(move(from(the(rest(position(is(the(A) amplitude(of(the(wave.(((B)(wavelength(of(the(wave.(((C)(frequency(of(the(wave.(((D)(speed(of(the(wave.(

(29. Which(of(the(following(affects(the(speed(of(sound(waves(traveling(through(the(air?(

A)(how(loud(the(sound(is(((B)(the(air(temperature(((C)(how(often(the(sound(is(repeated(((D)(the(amplitude(of(the(waves((

30. When(a(wave(hits(a(surface(through(which(it(CANNOT(pass(and(bounces(back,(it(undergoes(A) reflection.(((B)(refraction.(((C)(constructive(interference.(((D)(destructive(interference.(

(31. The(bending(of(waves(due(to(a(change(in(speed(is(called(

((((((reflection.(((B)(refraction.(((C)(diffraction.(((D)(interference.((

32. The(bending(of(waves(around(the(edge(of(a(barrier(is(known(as(((((((reflection.(((B)(refraction.(((C)(diffraction.(((D)(interference.((

33. Any(smooth(surface(that(reflects(light(to(form(an(image(is(a(n)(____.(A)(lens(((B)(microscope(((C)(mirror(((D)(telescope(

(34. You(can(hear(sounds(from(around(corners(because(of(

a)(refraction.(((B)(reflection.(((C)(diffraction.(((D)(elasticity.((

35. The(speed(of(sound(depends(on(a)(the(loudness(of(the(sound.(((B)(the(pitch(of(the(sound.(((C)(the(source(of(the(sound.(((D)(the(type(of(the(medium(it(travels(through.(

(36. Electromagnetic(waves(can(transfer(energy(without(a(n)(

a)(medium.(((B)(electric(field.(((C)(magnetic(field.(((D)(change(in(either(a(magnetic(field(or(an(electric(field.((

37. The(range(of(electromagnetic(waves(placed(in(a(certain(order(is(called(the(a)(electromagnetic(spectrum.(((B)(electromagnetic(wavelength.(((C)(electromagnetic(frequency.(((D)(electromagnetic(field.((

38. The(bending(of(light(rays(as(they(enter(a(new(medium(is(called(a)(diffuse(reflection.(((B)(regular(reflection.(((C)(refraction.(((D)(diffraction.((

39. What(happens(when(light(passes(from(air(into(water?(A) The(light(speeds(up.(((B)(The(light(continues(at(the(same(speed.(((C)(The(light(slows(down.(((D)(The(light(forms(a(mirage.(

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