Sound and Electromagnetic EnergyWaves 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.

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

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

Review Questions

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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? _________________________

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 Questions7. 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• 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.• Microwave radiation is used in communications, cell phones, satellites, and in cooking. It is absorbed by

food, which causes the food to heat up.• Radio waves have the longest wavelength. They are used to transmit radio and TV signals. Reflected radio

waves can give us ground images in the dark or through clouds.• X-rays have great penetrating power and are used to examine bones, teeth, and luggage.

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Speed of sound in different mediums.Fastest Solid

Middle Liquid

Slowest Gas

Review Questions13. 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 __________________________. Light Energy

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

transmitted or absorbed and converted into thermal energy.

Review Questions

18. The ________________ is a measure of how much a ray of light bends when it passes from one medium into another.19. We see objects because the objects _________________ light.20. A light colored, smooth surface will _______________________ light more than a dark, rough surface.21. A black shirt will tend to __________________________ light energy22. Clear glass will ___________________ light.

Heat Energy• Another form of electromagnetic energy is infrared radiation, also known as heat.• Matter is made up of tiny atoms and

particles• Particles are always in motion even if the

object they make up is not moving.• The particles move faster and further apart

as heat is added. • Most substances expand when heated.• Most materials Contract when Cooled.• Water is the only known substance that will expand when cooled. Example: ICE• When the ball is heated the particles will move faster and farther apart causing the heated ball not to fit through

the ring• Temperature is a measure of the average kinetic energy of individual particles of matter.• Thermal energy (heat) is the total energy of all particles.• Thermal energy (heat) and temperature are not the same.• The faster the particles move the more kinetic energy they have. • Even if 2 samples of matter are at the same temperature, they do not necessarily have the same total energy.• The more particles a substance has at given temperature the more thermal energy it has.• As thermal energy increases the motion of particles increases.

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• Thermal energy always moves from a warmer object to a cooler object until they reach the same temperature. • HIGH TO LOW GIVES FLOW UNTIL EQUILLIBRIUM IS REACHER • Substances will heat faster or slower depending on their color, texture, and type of material. • Dark colors absorb energy faster than light colors. • Rough surfaces will absorb faster than smooth surfaces that reflect energy.• Soil heats faster than water, but will cool faster as well.

Review Questions23. Heat is a form of electromagnetic energy known as ________________radiation.24. Most substances will _________________ when cooled.25. Water will ________________ when it freezes.26. When thermal (heat) energy is added, the temperature ________________.27. If thermal energy is transferred from object A to object B, the temperature of object A ____________.28. Heat always goes from a warmer object to a ___________ object until the _________ temperature is reached.29. A dark shirt becomes warm due to ______________.30. A shiny smooth surface will _______________ thermal energy.

Changes in the Phases of Matter

• • Physical Change alters the form of a substance, but does not change it to another substance.

• Example is any type of phase change.• Matter can change state when heat is added or

released.• When a material is heated, molecules gain energy move

faster and further apart.• When a material is cooled, molecules lose energy, move

slower and closer together.• A substance’s freezing point is the temperature at which its liquid form to a solid.• A substances boiling point is the temperature when it evaporates, or changes from a liquid to a gas.

Review QuestionsWhat states of matter of a pure substance are represented in the graph? A)___________ B)___________ C)__________

31. As a substance changes state, there is no change in the ____________________ of the substance.

32. What change of state and energy added or released at that line segment. A → B ____________________ C → B ____________________ B → A ____________________ B → C ____________________

33. The melting point of benzene is_________ and boiling point of benzene is ______________.

Methods of Thermal Energy Transfer Heat is the movement of thermal energy from a substance at a higher temperature to another at a lower temperature.

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Phase Change Thermal energy added or released

Phase to Phase

Melting Added Solid to LiquidVaporization Added Liquid to GasFreezing Released Liquid to SolidCondensation Released Gas to Liquid

Heat is thermal energy moving from a warmer object to a cooler object.

Heat Transfer

Method Examples

Conduction

Conductors

Insulators

Heat is transferred from one particle of matter to another without the movement of matter itself.

A material that conducts heat well.Example: tile, aluminum can

A material that does not conduct heat well.Example: blanket, fiberglass insulation, thermos

Convection Is the movement that transfers heat within water.

Heat is transferred by the movement of current within a fluid (a gas or liquid).Convection Current : A current caused by the rising of heated fluid and the sinking of cooled fluid.

Radiation Is the transfer of energy by electromagnetic waves.

Does not require matter to transfer thermal energy.

Review QuestionsDescription Radiation Conduction Convection

a. Radio waves travel through spaceb. Heat travels through a metal spoonc. Electricity travels through an electric cordd. Food is warmed in a microwavee. Ocean water circulates by currentsf. Sunlight passes through a window

34. Fiberglass is a common ____________________, which is a material that reduces the transfer of heat.35. Bare feet feel colder on a tile floor than on a rug because the tile floor is a better ____________________ of heat.

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36. The most disorganized state of matter is the ____________________ state.37. During a change of state, the addition or loss of ____________________ energy changes the arrangement of the

particles in the substance.38. The burning of wood is an example of a(n) ____________________ change.39. The characteristic temperature at which a pure solid changes to a liquid is its ____________________ point.40. Dissolving a spoonful of sugar in tea or coffee is an example of a ____________________ change. 41. Heat is transferred directly from one particle of matter to another by the process of __________________.42. A (n) ________________________is a material that transfers heat well.43. ________________________ is a transfer of thermal energy from a warmer object to a cooler object.44. A circular motion of warmer fluid and cooler fluid is called a (n)________________________.45. Stars transfer thermal energy by the process of ____________________.46. Complete Chart Below

Description Physical Change Chemical ChangeOccurs when energy is added or removedA new substance is produced.A substance changes form, but it remains the same substance.Freezing water is an example

Base your answers to questions 1 and 2 on the diagram and on your knowledge of science. The diagram shows an aluminum can before and after it was crushed.

1. Explain why crushing the aluminum can is an example of a physical change and not a chemical change. [1]

____________________________________________________________________________

_______________________________________________________________________________________________

2. Making cans from newly mined aluminum ore uses a large amount of energy. Therefore, old aluminum cans are often recycled to make new ones. State one positive effect recycling aluminum has on the environment. [1]

________________________________________________________________________________________________ _______________________________________________________________________________________________Base your answers to questions 3 through 5 on the diagram below and on your knowledge of science. The diagram shows a phase change represented by letter A.3. State the term for the phase change that occurs at A. [1]

__________________________________________

4. Explain why the phase change at A is a physical change. [1]

______________________________________________________________________________________________

_____________________________________________________________________________________________

5. Explain why the 100 grams of ice would have a greater volume than 100 grams of water. [1]

______________________________________________________________________________________________

______________________________________________________________________________________________

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Base your answers to questions 6 and 7 on the information and on your knowledge of science. The diagram shows a person observing a thunderstorm located several kilometers away. The person hears the thunder several seconds after seeing the lightning.6. Identify a form of energy, other than light and sound, that is often present

during a thunderstorm. [1] ____________________________________

7. Explain how sound travels through the air to the observer. [1] ______________________________________________________________________________________ ______________________________________________________________________________________

Base your answers to questions 8 and 12 on the diagram below and on your knowledge of science. The diagram shows a sequence of events. The ball and ring are made of the same metal.

8. What evidence shows that a physical change took place in the metal ball? [2]

__________________________________________________________________________________________

_________________________________________________________________________________________9. Explain why heating the metal ball caused this physical change. [1]

__________________________________________________________________________________________

__________________________________________________________________________________________

10. Explain why this is not evidence of a chemical change. [1]

__________________________________________________________________________________________

__________________________________________________________________________________________

11. Describe what can be done so that the metal ball will again go through the ring. [1]

__________________________________________________________________________________________

__________________________________________________________________________________________

12. State the relationship between the temperature of the metal ball and the speed of the molecules moving in the ball. [1]

___________________________________________________________________________________________ ___________________________________________________________________________________________

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The chart below shows temperature readings recorded every minute while a substance was being heated at a constant rate. The material was a solid before heating and a hot liquid after 7 minutes of heating.

Construct a line graph on the grid provided by following the steps below:

13. Use an X to plot the temperature at each time shown on the chart. [2]

14. Connect the Xs with a solid line. [1]15. Based on the data, at what temperature did a phase change take place? [1]

Circle the correct answer: (1) 35°C (2) 53°C (3) 58°C (4) 65°C

16. Was energy absorbed or released by the material during the phase change from a solid to a liquid? [1] Circle the correct answer: (1) absorbed (2) released

17. What would be an appropriate title for this graph? [1]_________________________________________________

18. What is the independent (manipulated) variable in this experiment? [1] ___________________________________

The diagram below shows an activity performed by a student in a classroom.

19. Complete the chart below by identifying one phase change that is occurring at each location.

Base your answers to questions 20 and 21 on the diagram below and on your knowledge of science. The diagram shows various forms of electromagnetic energy. Four forms of electromagnetic energy are listed below:

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Location

Phase Change Occurring

Pan A

Pan B

(1) visible light (2) ultraviolet light (3) x rays(4) microwaves

20. In the chart below, list these four forms of electromagnetic energy in order from the longest wavelength to the shortest wavelength. [1]Four forms of electromagnetic energy are listed below:

visible light ultraviolet light x rays microwaves

21. Complete the chart below by identifying the form of electromagnetic energy from the list that is described by each fact. Use each form of energy only once. [1]

visible light ultraviolet light x rays microwaves

Base your answers to questions 22 and 23 on the diagram and on your knowledge of science. The diagram shows one type of power facility that provides electricity for use in houses.

22. What phase change occurs in the boiler?

________________________ phase to _________________________ phase

23. Identify one fossil fuel that may be burned in the furnace shown. [1]

_________________________________________

Review Multiple Choice

1. A wet shirt is put on a clothesline to dry on a sunny day. The shirt dries because water molecules(1) gain heat energy and condense (3) gain heat energy and evaporate (2) lose heat energy and condense (4) lose heat energy and evaporate

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2. The diagram shows a metal spoon in a glass of water. Which process causes the metal spoon to appear split or broken?

(1) absorption (2) refraction (3) convection (4) reflection

3. The diagram below shows a glass containing a liquid and ice cubes. Which process causes water droplets to form on the outside of the glass?

(1) evaporation (2) condensation (3) freezing (4) melting

4. People often wear sunglasses in polar regions because most of the sunlight that strikes a snow-covered surface is

(1) reflected (2) absorbed (3) refracted (4) transmitted

5. The drawings below represent four different forms of electromagnetic energy. Which diagram represents electromagnetic energy with the shortest wavelength? (1) A (2) B (3) C (4) D

6. Water vapor changes to liquid water during which process?

(1) dissolving (2) melting (3) evaporation (4) condensation

7. The diagram shows a light ray.

In this diagram, the light ray is being

(1) transmitted (2) reflected (3) absorbed (4) refracted

8. A substance has a freezing point of –38°C and a boiling point of 356°C. At what temperature would this substance be in its liquid state?

(1) –100°C (2) –50°C (3) 80°C (4) 375°C

9. Which diagram best represents light being reflected after striking the flat surface of a mirror?

10. Which property of a substance indicates whether the substance is a liquid or a solid at room temperature?

(1) melting point(2) electrical conductivity (3) flexibility(4) solubility

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11. The diagram shows a boy observing a fish located at position B below the surface of the water. The boy sees the fish at position A. The apparent position of the fish is different from the actual position of the fish. What has happened to the light passing through the water to cause this difference?

(1) reflection (2) compression (3) absorption (4) refraction

12. Energy from the Sun reaches Earth mainly by the process of

(1) conduction (2) reflection (3) convection (4) radiation

13. A common characteristic of sound waves is that they(1) are created by vibrations (3) travel in straight lines toward the source (2) travel fastest through empty space (4) move at the speed of light

14. Which graph correctly shows the effect of heat energy on the motion of molecules of matter?

15. The diagram shows the relative wavelengths for several types of electromagnetic energy. Which type of electromagnetic energy has a shorter wavelength than ultraviolet waves?

(1) visible light (3) x rays

(2) microwaves (4) infrared light

16. Which graph best represents the relative distance between the particles of most substances in their solid, liquid, and gas states?

17. The picture below shows a ringing bell inside a vacuum jar.

As air is pumped from the vacuum jar, the sound level of the ringing bell will decrease until it can no longer be heard. This happens because air must be present in the jar in order for

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(1) sound to be transferred (3) electricity to flow through the wires

(2) the rubber to seal the jar (4) the bell clanger to vibrate

18. How is heat energy transferred within the liquid water in the pond?

(1) compound formation (2) chemical reactions (3) convection currents (4) nuclear reactions

Base your answers to questions 19 and 20 on the diagram below, which shows two insulated Styrofoam cups of water connected by an aluminum bar. The thermometers show the temperature of the water in cup A and cup B at the beginning of a heat-flow experiment.

21 Over the next 15 minutes, which changes would most likely occur?(1)  The temperature in cup A will decrease and the temperature in cup B will increase. (2)  The temperature in cup A will decrease and the temperature in cup B will decrease. (3)  The temperature in cup A will increase and the temperature in cup B will increase. (4)  The temperature in cup A will increase and the temperature in cup B will decrease.

22  Which process is most responsible for the temperature changes that will take place? (1)  radiation of heat from the water in the cups to the thermometers (2)  conduction of heat through the aluminum bar (3)  radiation of heat from the water in the cups into the air (4)  conduction of heat through the air to the water in the cups

19. The diagram below represents several forms of electromagnetic energy. Which feature best distinguishes one form of electromagnetic energy from another?

(1) color (2) wavelength(3) surface temperature (4) distance traveled

20. The diagram shows a Bunsen burner heating a beaker of water on a beaker stand. The arrows represent the transfer of heat energy in the water. Which process is primarily responsible for the transfer of heat indicated by the arrows in the beaker of water?

(1) conduction (2) convection (3) radiation (4) condensation

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21. Water at 20°C in an uncovered pan is evaporating very slowly. What could be done to the water to make it evaporate more quickly? (1) Cover it. (2) Heat it. (3) Place it in the dark. (4) Put salt in it.

22. Which process is an example of a physical change?

(1) wood burning (2) ice melting (3) iron rusting (4) milk souring

23. The diagram shows water being heated in a flask. The flask has a rubber stopper with a glass tube extending through it. The current level of the water in the glass tube is indicated. The temperature of the water is 25°C. If heating continues, the water in the glass tube will most likely

(1) turn into a solid (3) become more dense (2) move into the flask (4) rise higher in the tube

24. Convection currents, which may be the driving force for the movement of lithospheric plates, are mostly found in Earth’s

(1) crust (2) outer core (3) plastic mantle (4) inner core

25. Convection currents in Earth’s mantle are believed to be responsible for(1) ocean currents(2) crustal plate movements (3) climatic changes(4) uneven surface heating

26. Which diagram best represents molecules of matter in the solid phase?

27. The diagram below shows what occurs when a ray of light strikes and enters a pond. Which property of light is illustrated when the ray enters the pond?

(1) refraction (2) absorption (3) reflection (4) emission

28. The arrows in the diagram below show the circulation of air on a sunny day.

The air circulation shown is caused by(1) both hot air and cool air sinking (2) both hot air and cool air rising (3) hot air sinking and cool air rising (4) hot air rising and cool air sinking

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29. Which form of energy are x rays and ultraviolet light?

(1) nuclear (2) heat (3) electromagnetic (4) chemical

30. Sound will not travel in a (1) solid (2) liquid (3) gas (4) vacuum

Base your answers to questions 31 and 32 on the diagram below and on your knowledge of science. The diagram represents four processes, labeled A, B, C, and D, that occur when water changes phase.

31. Which process is represented by B?

(1) condensing (2) evaporating (3) freezing (4) melting

32. Which two processes increase the motion of the molecules?

(1) A and B (2) C and D (3) B and C (4) D and A

33. Energy from the Sun reaches Earth mainly by the process of

(1) conduction (2) reflection (3) convection (4) radiation

Base your answers to questions 34 and 35 on the diagrams below and your knowledge of science. The diagrams show liquid water changing to water vapor in four different situations.

34. Which observation would be evidence that the water is undergoing a phase change? (1)  Waves form on the top of the pond. (2)  Water soaks into the wet sand. (3)  The water splashes out of the swimming pool. (4)  The water level in the glass of water decreases.

35. How is heat energy transferred within the liquid water in the pond?

(1) compound formation (2) chemical reactions (3) convection currents (4) nuclear reactions

Extra Questions

Which statement best describes the property of light waves illustrated in the diagram below?

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(1) Some materials absorb light waves.(2) Some materials reflect light waves.(3) Light waves are refracted by some materials. (4) Light waves are emitted by some materials.

The diagram below shows a pencil in a glass of water.

When viewed from the side, the pencil appears to be broken. What process causes this to happen?

(1) absorption (3) reflection (2) evaporation (4) refraction

Skiers often wear sunglasses while they are skiing because snow

(1) radiates light (2) absorbs light (3) conducts light (4) reflects light

Heat was applied at a constant rate to a solid substance under controlled conditions. The temperature of the substance was recorded every 3 minutes. These data are recorded in the table below.

Use the grid to construct a line graph from the data in the table. Follow the steps below. a Use Xs to plot the data for time and temperature. [1]

Draw a solid line that connects the Xs. [1]

Provide an appropriate title for the graph. [1] Title: ___________________________________

According to your graph, what would the temperature of the substance be at 23 minutes? [1] _______ °C

What is the independent (manipulated) variable in this experiment? [1]

If heat was added at a constant rate to the solid substance, why did the temperature remain at 16°C for approximately 6 minutes? [1]

______________________________________________________________________________________ ______________________________________________________________________________________

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