7c. Compare and contrast the different forms of energy (heat, light, electricity, mechanical motion, sound) and their characteristics.
8Light (radiant)—is electromagnetic energy ex. Sunlight, X-rays, Forms of Energy:Heat (thermal)—the vibration and movement of the atoms and molecules within substancesex. Atoms move faster in hot water vs. ice waterLight (radiant)—is electromagnetic energyex. Sunlight, X-rays,microwaves, p.636Electricity—energy of moving electrons, typically moving through a wireex. lightening
9Sound—energy caused by an object’s vibrations Mechanical Motion—is energy stored in a moving object or an object that can movePE + KE = mechanical energyex. Wind, Jack in the Box
10ex. Cells in our body store chemical energy Chemical—energy stored in the bonds of atoms and molecules (is released during chemical changes when atoms are rearranged)ex. Cells in our body store chemical energyNuclear—energy stored in the nucleus of an atom — the energy thatholds the nucleus togetherex. Nuclear power plants
11d. Describe how heat can be transferred through matter by the collisions of atoms (conduction) or through space (radiation). In a liquid or gas, currents will facilitate the transfer of heat (convection).
12Conduction is the transfer of energy through matter from particle to particle as they touch. Transfer of heat energy from atom to atomMost effective in solids.Heat moves from warmer substances to cooler substances.
13Convectionthe transfer of thermal energy by the movement of a gas or liquid (a medium).The circular motion caused by density differences that result from temperature differences are called convection currents.
14Radiationthe transfer of thermal energy byelectromagnetic waves such as visible lightand infrared waves. (See p ).This energy can be transferred throughparticles of matter OR empty space!ExamplesEnergy from the sunMicrowaves use radiation
15Review QuestionsWhich of the following converts electricalenergy into mechanical?A light switch B electric stoveC light bulb D electric fan
16According to the Law of Conservation of Energy, if Sally throws a watermelon with 100 joules of energy off the roof of a building, how much energy should the watermelon have as it hits the ground?200 joules B joulesC. 100 joules D. 0 Joules
17When a rock is thrown straight up into the air, it reaches its highest point and briefly comes to a complete stop before it starts to fall back to the ground. Which is greatest at the point where the rock stops?A. potential energyB. kinetic energyC. force due to gravityD. friction
18A house becomes warm after air circulates in the house A house becomes warm after air circulates in the house. What type of heat transfer happens?ConductionConvectionRadiation
19Why do we insulate our soda cans? To keep heat inTo keep heat outTo keep cold inTo keep cold out
20Where is kinetic energy the greatest? A B C DWhere is potential energy the greatest?
21Tonya drops a ball off a cliff as shown in the picture Tonya drops a ball off a cliff as shown in the picture. Which position shows where the ball has the most kinetic energy and the least potential energy?A) AB) BC) C
22Bob sat by the pool too long and his skin began to burn Bob sat by the pool too long and his skin began to burn. What type of heat transfer occurred to make him burn?ConductionConvectionRadiation
23At which position in the pendulum swing is kinetic energy greatest? a. A b. Bc. C d. DAt which position in the pendulum swing is potential energy the lowest?
24What type of heat transfer is happening in the picture? A. Heat to electricalB. Chemical to mechanicalC. Mechanical to lightD. Heat to mechanicalWhat type of heat transfer is happening in the air around the candle?ConductionConvectionRadiation
25A gasoline-powered vehicle goes up a hill from point X to point Y A gasoline-powered vehicle goes up a hill from point X to point Y. What energy transformation must occur in the car’s engine?A Chemical energy into mechanical energyB Electrical energy into light energyC Electrical energy into sound energyD Mechanical energy into light energy
26When walking along an asphalt street after sundown, a person often feels heat coming off the pavement. The heat is moving from the asphalt to the person byA. Conduction B. convectionC. Expansion D. radiationHeat, light, and electricity are all forms ofA. Atoms B. energyC. Cells D. motion
27The batteries in a flashlight make electricity using A. chemical B. solarC. heat D. mechanicalIn the pictures below, the candle is heating the water in the tank. Which picture shows how the water will move as it gets hot?
28My dog, Ralph, wears slippers on hot days because the pavement is hot on his feet. What type of heat transfer makes his feet hot?ConductionConvectionRadiation
29S8P3. Students will investigate relationship between force, mass, and the motion of objects. a. Determine the relationship between velocity and acceleration.
30Velocity—the speed of an object in a particular directionvelocity must include speed (distance over time) and direction!ex. an airplane travels west at 600 km/hif speed or direction changes the velocity changes
31Practice:Tom is traveling west at 50 miles per hour. Sally and her family are traveling south at 50 miles per hour. Do the cars have the same velocity? Why or why not?TomSally
32Acceleration—The rate at which velocity changesAn object accelerates if its speed ordirection changesan increase in velocity is called positiveaccelerationa decrease in velocity is called negativeacceleration or decelerationthe faster the velocity changes, the greaterthe acceleration
33b. Demonstrate the effect of balanced and unbalanced forces on an object in terms of gravity, inertia, and friction.
34Balanced ForcesOccur when the forces on an objectproduce a net force of 0 Newtons (N)Will not cause a change in the motion of amoving objectWill not cause a nonmovingobject to start movingex. Hat on your head, bird’s nest
35Unbalanced ForcesOccur when the net force on an object isnot 0 Newtons (N)The forces are unbalancedProduce a change in motionAre necessary to start movement orchange movementex. kicking a ball
36Decide whether the following pictures represent a balanced or unbalanced force
37Yes, you really are attracted to your science book! Gravity—A force of attraction between objects dueto their massesLaw of Universal Gravity—all objects in theuniverse attract each other throughgravitational force+Yes, you really are attracted to your science book!
38a. Recognize that every object exerts gravitational force on every other object and that the force exerted depends on how much mass the objects have and how far apart they are.
39Gravity decreases as distance increases. The more mass, the moregravitational force
40The tendency of objects to resist any changes in motion Inertia—The tendency of objects to resist anychanges in motionThe more mass the more inertiaMore mass more inertiaLess mass less inertia
41Friction—A force that opposes motion between twosurfaces that are in contactCan cause a moving object to slow downand eventually stopCaused by roughness of surfaces
42c. Demonstrate the effect of simple machines (lever, inclined plane, pulley, wedge, screw, and wheel and axle) on work.
43Inclined Plane—A flat slanted surfaceLess input force necessary, but must be exerted over a longer distanceExamples: ramps, stairs,
44Wedge—Device that is thick at one end and tapers to a thin edge at the other end (two inclined planes back to back)The longer and thinner the wedge, the less input force is required (same as with the inclined plane)Examples: End of an ax, knife, zipper,Push pin
45An inclined plane wrapped around a cylinder Screw—An inclined plane wrapped around a cylinderThe closer the threads, the greater the mechanical advantage (longer distance, but less input force needed)Examples: Jar lid, bolts, faucetsThe closer the threads the greater the mechanical advantage
46Two circular objects fastened together that rotate about a common axis Wheel and Axle—Two circular objects fastened together that rotate about a common axisThe object with the larger diameter is the wheel and the object with the smaller diameter is the axleMultiplies your force, but you must exert your force over a longer distanceExamples: door knobs, steering wheels, screw driverswheelaxle
473 different classes (types) of levers 1) 1st Class Levers— A rigid bar that pivots or rotates about a fixed point called a fulcrum3 different classes (types) of levers1) 1st Class Levers—Fulcrum (pivot point) is located between the input and output force (the load).Change the direction of the force (they can also change size or distance of the force)Examples: Seesaw, scissors, pliers, catapultEffortLoadEffortFulcrumFulcrumOutput/load
48The load is between the fulcrum and input force (effort) 2nd Class Levers—The load is between the fulcrum and input force (effort)Do not change the direction of the input forceYou must exert less force over more distanceExamples: Bottle openers, wheelbarrowsInput force (effort)fulcrumload
49The input force (effort) is between the fulcrum and the load 3rd Class Levers—The input force (effort) is between thefulcrum and the loadDo not change the direction of the input forceDoes not multiply your input force (effort) but allows you to apply a lot of force over a shorter distanceExamples: Tweezers, Rake, baseball bat, Hammer
501st Class– fulcrum in the middle Remember FLE1st Class– fulcrum in the middle2nd Class– load is in the middle3rd Class– Effort (input force) is in the middleloadInput force (effort)fulcrumOutput/loadeffortfulcrum
51Pulley—Grooved wheel with a rope(or chain, or cable) wrapped around itCan change the amount and direction of your input forceFixed Pulleys—A pulley attached to a structureDoes not change the amount of input forceChanges the direction of the input forceExample: flag pole, sail boat, elevators
52Moveable Pulley—A pulley attached to the object being movedDoes not change the direction of the forceDoes increase your force—you use less force over more distanceExample: a crane
53Pulley System (Block and Tackle)— Combination of fixed and moveable pulleysChanges the size and direction of the force you exert
54Review QuestionsWhich characteristic of motion could change without changing the velocity of an object?A the speed B the positionC the direction D the acceleration
55What two forces are responsible for keeping Earth in orbit around the sun? Gravity and frictionGravity and inertiac. Friction and inertiad. Strong force and inertiaWhich of the following represents the velocity of a moving object?
56A spring scale is pulled downward and readings are recorded. If the spring is pulled 3.5 cm, the spring scale should readA 12 N. B 13 N.C 14 N. D 15 N.
57A ball is dropped from the top of a tall building A ball is dropped from the top of a tall building. As the ball falls, the upward force of air resistance becomes equal to the downward pull of gravity. When these two forces become equal in magnitude, the ball willA flatten due to the forces.B fall at a constant speed.C continue to speed up.D slow to a stop.
58What is the net force on the cart above? A 50 N. B 150 N.C 200 N. D 350 N.
59This box will increase in speed A downward and to the left.B downward and to the right.C upward and to the left.D upward and to the right.
60When you bend your arm at the elbow, the bones and muscles in your arm are acting as a system. What simple machine does this system represent?A. inclined plane B. pulleyC. Wedge D. leverWhich simple machine is a pair of scissors?A. wheel and axleB. pulleyC. inclined planeD. lever
61On Earth, an astronaut has a mass of 140 kg On Earth, an astronaut has a mass of 140 kg. When the astronaut goes into space, shewill have a mass of 140 kg, but will have less weight.will have less mass and weight.will have a mass of 140 kg, and have a weight of 140 kg.will have less mass and a weight of 140 kg.
62A person dives out of a nonmoving boat in the direction indicated by Arrow A. Which arrow shows the direction in which the boat would move?A. Arrow AB. Arrow BC. Arrow CD. Arrow D
63Which term refers to the rate of change of motion? A. Acceleration B. speedC. Momentum D. velocityThe tendency for a body at rest to remain at rest is known asA. inertiaB. torqueC. momentumD. mass
64Where should Melissa position the fulcrum in order to minimize the amount of force needed to lift the box?Point A B. Point BC. Point C D. Point D
65Which force causes a moving object to slow and then stop? A. Acceleration B. inertiaC. Friction D. lift
66S8P4. Students will explore the wave nature of sound and electromagnetic radiation. a. Identify the characteristics of electromagnetic and mechanical waves.
67All are transverse waves Electromagnetic Waves—Waves that do not need a medium—a substance through which the wave can travelAll are transverse wavesEx. light, microwaves, TV &Radio waves, X-raysMechanical Waves—Waves that need a medium—a substance through which the wave can travelCan be transverse or longitudinalEx. sound waves, ocean waves
68b. Describe how the behavior of light waves is manipulated causing reflection, refraction diffraction, and absorption.
69Reflection—occurs when waves bounce off an objectWe see objects as different colors when that color is reflected back at usEx.—A leaf appears green because it reflects green light
70Absorption–The transfer of energy carried by light to particles of matterThe farther light travels from its source the more it is absorbed by particles (this is why light becomes dimmer)
71Refraction—The bending of a wave as it passes from one medium to anotherLight travels slower through matter causing light to bend
72Diffraction—The bending of waves around barriers or through openingsAmount of diffraction depends on wavelength and size of barrier or openingWavelength of light is small so it cannot bend very much
73c. Explain how the human eye sees objects and colors in terms of wavelengths.
74We see different wavelengths of visible light as different colors Longest wavelengths are redShortest wavelengths are violetROYGBIV
75d. Describe how the behavior of waves is affected by medium (such as air, water, solids).
76Sound travels quickly though air Even faster through liquids Sound through media—Sound travels quickly though airEven faster through liquidsFastest through solidsWarmer objects will conduct sound fasterWhy?Particles move faster in warm object so they transfer the sound faster
77e. Relate the properties of sound to everyday experiences.
78Sound—a longitudinal wave caused by vibrations and carried through a substancehas to travel through a medium
79Doppler Effect—Apparent change in the frequency of a sound caused by the motion of the listener or the source of the soundThe sound will have a higher pitch as it approachesWill have a lower pitch as it leaves
80Echo—Reflected sound waveOccur when sound bounces off a flat hard surface
81f. Diagram the parts of the wave and explain how the parts are affected by changes in amplitude and pitch.
82Parts of the wave—Crest—the highest point of a transverse waveTrough—the lowest point of a transverse waveWavelength—the distance from any point on one wave to an identical point on the next waveAmplitude—the maximum distance that the particles of a wave vibrate from their rest position
84Remember:AL PFAmplitude/loudness Pitch/FrequencyThe amplitude of a wave is related toheight.The greater the amplitude the louder thesound and the more energy it has.
85This wave will sound loud This wave will sound quietThis wave will sound loud
86Frequency—the number of waves produced in a given amount of time The frequency of a wave determines pitch.A wave with a high frequency has a high pitch.A wave with a low frequency has a low pitch.
87This wave would have a high pitch. This wave would have a low pitch.
88Review QuestionsWhich color reflects all colors of light?A. black B. whiteC. green D. redWhen Marcia yelled from the top of a canyon, an echo was created. This happened because the sound waves of her voice bounced back from the canyon walls. Which property of waves occurred?A. Diffraction B. reflectionC. Interference D. refraction
89There is only one fish in the fishbowl below There is only one fish in the fishbowl below. When Joseph looks down at the fish, the image he observes is closer to the surface than the actual location of the fish.Which wave characteristic does Joseph’s observation demonstrate?A. amplitude B. diffractionC. reflection D. refraction
90Why are light-colored clothes cooler to wear in the summer than dark-colored clothes? A. Light-colored clothes let more air in.B. Light-colored clothes prevent sweating.C. Light colored clothes are not as heavy as dark-colored clothes.D. Light-colored clothes reflect more light than dark-colored clothes.
91A family is building an outdoor shower at their cottage by hanging a plastic container from a post, as shown above. The container will be exposed to full sunlight. What color should the container be to make the water as warm as possible?A. White B. yellowC. Black D. red
92In old movies, people sometimes put their ear on a railroad track to see if a train is coming. This works because the iron railA. is heated by frictionB. carries sound better than airC. is cooler than airD. is connected directly to the train
93Sound A has a shorter wavelength than Sound B Sound A has a shorter wavelength than Sound B. This means that Sound A willA. be louder than Sound B.B. be softer than Sound B.C. have a lower pitch than Sound B.D. have a higher pitch than Sound B.
94Sound can travel fastest through A. Air B. metalC. Water D. outer space
95A. B. C. D.Which wave has the highest frequency?Which wave has the highest pitch?Which wave has the softest sound?Which wave has the loudest sound?
96S8P5. Students will recognize characteristics of gravity, electricity, and magnetism as major kinds of forces acting in nature.b. Demonstrate the advantages and disadvantages of series and parallel circuits and how they transfer energy.
97Types of Circuits: Series and Parallel Series Circuits—All parts of the circuit are connected in a single loopOnly one path for charges to followAll loads share the same current
98DisadvantagesOnly one pathway for moving chargesIf there is a break in the circuit charges stop flowing(ex. if one light blows all the lights go out)AdvantagesBurglar alarms use series circuits
99Parallel Circuits—Loads are connected side by sideCharges have more than one path on which they can travelLoads do not have the same current (each light will shine at full brightness)houses are wired in parallel
100c. Investigate and explain that electric currents and magnets can exert force on each other.
101Electric Current—The rate at which charges pass a given pointExpressed in amperes (amps)
102How an object becomes charged… If it loses electrons it becomes positively chargedIf it gains electrons it becomes negatively chargedCharged objects create electric forceGreater the charge, the greater the forceCloser the charges, the greater the force
103Magnets-Anything that attracts iron or things made of ironHave two poles (strongest attraction here)Exert force on each other (magnetic force)Surrounded by magnetic field
104Electromagnetism—Interaction between electricity and magnetismElectric currents produce a magnetic field
105Review QuestionsAt which location is Earth’s magnetic field the strongest?1 B. 2C D. 4
106In which circuit will the bulb light up? A.B.C.D.
107Which best describes a parallel circuit? A Electricity flows along one pathway.B The flow of electricity comes from one source.C Electricity flows along more than one pathway.D The flow of electricity comes from more than one source
108Three identical light bulbs are connected in parallel with a battery, as shown, and all are lit. If bulb I is unscrewed and removed, what will happen to the other two light bulbs?A. Both will stay lit.B. II will go out, but III will stay lit.C. II will stay lit, but III will go out.D. Both will go out.
109The bulb in the electric circuit will NOT light because A. the switch is too far away from the bulbB. the bulb has to be largerC. the wires are not long enoughD. there is no energy source
110Which electromagnet will pick up the most paper clips? B.C.D.