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8 th Physical Science Kathy During. Lesson 1 – Circuit of Inquiries – A Preassessment.

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Presentation on theme: "8 th Physical Science Kathy During. Lesson 1 – Circuit of Inquiries – A Preassessment."— Presentation transcript:

1 8 th Physical Science Kathy During

2 Lesson 1 – Circuit of Inquiries – A Preassessment

3 Inquiry 1.1 The Single Pulley Procedure –Materials: –1. –2. –3……

4 Inquiry 1.1

5

6 Conclusion A pulley changes the direction of a force.

7 Inquiry 1.2 The Pegboard Lever Procedure – Materials –1. –2. –3. …..

8 Inquiry 1.2

9

10 Conclusion As washers are added, they are placed closer to the pivot point. Fewer washers are placed farther from the pivot point.

11 Inquiry 1.3 The Hand Warmer Procedure –Materials –1. –2. –3……

12 Inquiry 1.3

13

14 Conclusion Temperature increased due to friction.

15 Inquiry 1.4 Constructing a Graph Procedure –Materials: –1. –2. –3……

16 Inquiry 1.4

17

18 Conclusion The ball slowed down over time.

19 Inquiry 1.5 Transforming Energy Procedure –Materials: –1. –2. –3……

20 Inquiry 1.5

21

22 Conclusion The hand’s kinetic energy (motion) converted to electrical energy. The electrical energy becomes heat and light in the bulb.

23 Inquiry 1.6 The Puck Launcher Procedure –Materials –1. –2. –3…….

24 Inquiry 1.6

25

26 Conclusion The farther back the puck is pulled, the longer the time it takes for it to stop. Friction stops the puck.

27 Inquiry 1.7 Up the Incline Procedure –Materials –1. –2. –3……

28 Inquiry 1.7

29

30 Conclusion It requires a stronger force to pick up the mass. It requires less force to pull the mass up the incline but it is moved across a greater distance.

31 Inquiry 1.8 Down the Ramp Procedure –Materials –1. –2. –3……

32 Inquiry 1.8

33

34 Conclusion Gravity is the force that accelerates the car down the incline. Friction stops the car.

35 Vocabulary – Lesson 1 1.Galileo Galilei -- born in Pisa, Italy – 1564; Recorded observations – shared imaginative and creative mind; Inventor (telescope) – discovered four moons of Jupiter; Astronomer; Believed earth revolved around the Sun – controversial idea to leaders of the Church – put on trial for heresy – kept under house arrest for the rest of this life.

36 Lesson 2

37 Lesson 2 - Making a Battery You will build a zinc-copper battery cell and observe the chemical reactions and energy transformations that occur.

38 Lesson 2

39 Question How do you make a battery? L 2

40 Lesson 2 If _________________,then __________ because _________________.

41 Lesson 2 Materials

42 Lesson 2

43

44 L2 A battery contains a limited amount of energy. The electrical energy that a battery supplies is the result of chemical reactions between the electrodes and the electrolyte in the battery.

45 THREE MAIN COMPONENTS OF A BATTERY Negative terminal – (zinc) – accumulates negative charge (gains electrons). Positive terminal – (copper) – accumulates positive charge (loses electrons). Electrolyte – a liquid solution or a paste whose molecules spontaneously separate into positively or negatively charged atoms or groups of atoms, called ions. L 2

46 Oxidation-Reduction Reaction The battery is assembled by putting a copper and zinc strip in a container filled with a copper sulfate solution (electrolyte). A chemical process called oxidation- reduction reaction occurs. In this reaction, the zinc electrode easily accumulates electrons; the copper electrode loses electrons. The gain or loss of electrons at an electrode is the result of chemical reactions between the electrodes and the electrolyte. This accumulation of opposite charges on the electrodes produces the electric potential of the battery. The battery’s electric potential – how much electrical energy per charge the chemical reaction generates – is measured in volts. L2

47 How the Battery Works Chemical reactions at the electrodes create a current when the assembly is placed in the copper sulfate solution. At the zinc electrode, a reaction occurs in which zinc atoms lose two electrons each to the zinc strip and are converted into positively charged zinc ions that go into the solution. This conversion of metallic zinc into aqueous zinc ions gradually eats away the zinc electrode. At the copper electrode, the positive copper ions in the copper sulfate solution gain two electrons each at the copper electrode, thereby becoming neutral metallic copper that accumulates on the electrode. This movement of ions in the electrolyte creates a current in the battery. L2

48 The wires that connect the light bulb to the battery provide a path for electrons released by the zinc to flow to the copper electrode. This movement of electrons creates a current in the wires and completes the circuit. As the current flows through the light bulb, the electrical energy associated with the electrons is transformed into light and heat in the bulb. L2

49 VOCABULARY – LESSON 2 In this lesson, we made a device composed of two metal electrodes in an electrolyte that transfers chemical energy into electrical energy. This device is known as a (2) battery. L2

50 VOCABULARY – LESSON 2 “Something is happening” when the bulb lights. This is evidence that the battery is a source of energy for the bulb. This ability to do work is: (3) energy. L2

51 VOCABULARY – LESSON 2 The battery is made of two metal strips, copper and zinc. The zinc strip is negatively charged because it gains electrons. The copper strip is positively charged because it loses electrons. The strips are (4) electrodes. Negatively-charged particles of an atom are (5) electrons. L2

52 VOCABULARY – LESSON 2 The liquid solution in the battery is an (6) electrolyte. A battery with a liquid electrolyte is a (7) wet-cell battery. A battery with an electrolyte made of paste is a (8) dry-cell battery. L2

53 VOCABULARY – LESSON 2 The light eventually stopped burning after being removed from the copper sulfate solution. The chemical reaction could only generate a certain amount of electrical energy per charge. This is the (9) electric potential of the battery. The electric potential of the battery is measured in (10) volts. This is named after the person who built the first electric battery - (11) Alessandro Volta. A device made of two metal electrodes in an electrolyte that transfers chemical energy into electrical energy is a (12) battery. L2

54 Lesson 3

55 Lesson 3 - Rechargeable Batteries You will use rechargeable batteries to learn about stored energy and energy conversions. You will conduct an investigation to learn if different devices use energy at different rates.

56 Lesson 3

57 Question – Lesson 3 Do different devices use energy at different rates? What evidence do we have that energy is stored in a battery? L3

58 Lesson 3 If _________________,then __________ because _________________.

59 Lesson 3 Materials

60 Lesson 3

61 Light bulb v. motor 3 minute charging time Lit time of bulb v. running time of motor Light bulb Motor

62 L3 Different devices use energy at different rates. Energy can be transformed from one form to another. Energy can be stored in a battery.

63 Current flowing in the circuit carries energy. As the current flows through the bulb, the chemical energy stored in the battery becomes light and heat energy in the bulb. When all the battery’s available chemical energy has been converted to other forms of energy, the battery is “dead.” L 3

64 When a battery is charging, energy is being put into it. The charger runs a current “backward” through the battery, reversing the chemical processes and converting electrical energy to chemical energy, which is stored in the battery. The current is said to go backward because the flow of ions in the electrolyte is opposite to the flow when the battery is discharging and supplying electrical energy to a circuit. L3

65 The battery stores chemical energy – potential energy that is later transformed to electric potential energy. The charging process converts electrical energy to chemical energy. The chemical energy is later converted back to electrical energy, and then to heat and light in the bulb. L3

66 The cycle of charging and discharging batteries cannot continue indefinitely because of gases that escape from the cell and because of impurities in the cells. Eventually, rechargeable batteries must be replaced. L3

67 Vocabulary – Lesson 3 Energy stored in the battery is (13) chemical energy. The device in a car that generates an electric current when an engine runs and sends a current through a battery to charge it and keep it from running down is an (14) alternator. The electrodes in a car battery are also called (15) terminals. How much energy a battery will store and generate is the (16) capacity of a battery.

68 Lesson 4

69 Lesson 4 - Storing & Using Energy in a Battery You will charge batteries for different lengths of time and use them to light a flashlight. After charging the batteries for differing lengths of time, you will measure the time the flashlight remains lit.

70 Lesson 4

71 QUESTION – LESSON 4 How does charging time of battery affect lit time of bulb? How does charging time affect the stored energy in a rechargeable battery?

72 Lesson 4 If _________________,then __________ because _________________.

73 Lesson 4 Materials

74 Lesson 4

75 Charging Time v. Lit Time L4

76 Lesson 4

77 L4 The amount of energy stored in a rechargeable battery is proportional to the time the battery is charged.

78 Vocabulary – Lesson 4 The stored chemical energy is the battery is changed to electrical energy and heat and light in the bulb. These changes are energy (17) transformations. The amount of energy stored in a rechargeable battery is directly related to the amount of time the battery is charged. This relationship is (18) proportional. L4

79 Vocabulary – Lesson 4 Mechanical energy may be converted to electrical energy. The device that does this is a (19) generator.

80 Vocabulary – Lesson 4 A practical way to analyze data is to construct and interpret a graph. The data being controlled is the (20) independent variable. The independent variable is plotted on the (21) x-axis. The x-axis runs across or (22) horizontally. L4

81 Vocabulary – Lesson 4 The data that depends on the independent variable is (23) dependent variable. The dependent variable is plotted on the (24) y-axis. The y-axis runs up and down or (25) vertically. L4

82 Vocabulary – Lesson 4 The intersection of the two axes on a graph is the (26) origin. A line that goes through the middle of plotted data points on a graph is a (27) best fit line.

83 Lesson 5

84 Lesson 5 - Introduction to Forces You will investigate the elastic force of a rubber band by using a spring scale. You will measure the force at 2 cm. intervals over a distance of 20 cm.

85 Lesson 5

86 Question – Lesson 5 How is force and the elastic stretch of a rubber band related?

87 Lesson 5 If _________________,then __________ because _________________.

88 Lesson 5 Materials

89 Lesson 5

90 Elastic Force Created by Stretching a Rubber Band

91 Lesson 5

92 L5 A force is a push or pull. The elastic force a rubber band exerts is proportional to how much the rubber band stretches. The gravitational force on a body is directly proportional to the mass of the body. Mass is related to the amount of matter in a body. Weight is a measure of the force of gravity on an object.

93 L 5

94 Mass v. Weight WEIGHT is a measure of the force of gravity pulling on a body. MASS is a measure of how much matter is in a body. L 5

95 Weight v. Mass L L 5

96 Lesson 5 L 5

97 Vocabulary – Lesson 5 A push or a pull on an object is a (28) force. A tool used to measure force is a (29) spring scale. Before being used, a spring scale must be set or (30) calibrated. One type of force measured by a spring scale is (31) gravitational force. L5

98 Vocabulary – Lesson 5 The metric unit of force is the (32) newton (N). (We use the British system – ex. – pound (lb.), ounce (oz.), ton. 1 N = 1/5 lb. The international basis for scientific measurement is (33) metric units. L5

99 Vocabulary – Lesson 5 The measure of the force of gravity on an object is (34) weight. The metric unit for measuring weight is the newton (N). The amount of matter in an object is (35) mass. Mass is measured with a (36) balance. The common metric units for measuring mass is the (37) gram, kilogram. L5

100 Vocabulary – Lesson 5 The earliest and best known person for having studied the nature of gravitational force is (38) Isaac Newton. The force of attraction between two bodies is (39) gravitational force. It is directly proportional to the mass of an object – the greater the mass, the greater the gravitational force between two objects. It also depends on the distance between objects. –The gravitational force between two objects is inversely proportional to the square of the distance between the objects – if the distance between two bodies doubles, the gravitational force between them will be one-fourth as much. This is the (40) law of universal gravitation. L5

101 Vocabulary – Lesson 5 When the rubber band was pulled, it pulled back. For every action there is an equal and opposite reaction. This is (41) Newton’s third law of motion.

102 Vocabulary – Lesson 5 When something stretches when acted on by a force, it has the properties of (42) elastic force. The person to first describe the nature of elastic force was (43) Robert Hooke. Force is directly proportional to the stretch of a spring. This is known as (44) Hooke’s Law.

103 Lesson 6

104 Lesson 6 - The Force of Friction You will investigate the force of sliding friction on a wooden block. You will investigate surface type, weight, and surface area.

105 Lesson 6-1

106 Question – Lesson 6.1 Does friction depend on the type of surfaces in contact? Do different surfaces produce different amounts of friction? How is pulling force related to the force of friction?

107 Lesson 6-1 If _________________,then __________ because _________________.

108 Lesson 6-1 Materials

109 Lesson 6-1

110 Force Needed to Move a Block.27 m (27 cm.) Over Different Surfaces L 6-1

111 Lesson 6 L 6-1

112 L 6.1 Friction is the force that resists motion between two surfaces in contact with each other. The force needed to move an object across a horizontal surface at a constant speed is equal in magnitude, but opposite in direction, to the force of friction. Friction depends on the types of surfaces in contact.

113 Lesson 6-2

114 Question – Lesson 6.2 Does changing the load change the force of friction across a surface? If you add a larger load, will the force of friction change?

115 Lesson 6-2 If _________________,then __________ because _________________.

116 Lesson 6-2 Materials

117 Lesson 6-2

118 Force Needed to Move Two and Three Blocks 0.27 m (27 cm.) Over Different Surfaces

119 Lesson 6-2 L 6-2

120 The frictional force on an object moving across a horizontal surface is directly proportional to the weight of the moving object.

121 Lesson 6-3

122 Question 6.3 Does changing the surface areas in contact change the amount of friction? Does surface area affect friction? What is the relationship between surface area and friction ?

123 Lesson 6-3 If _________________,then __________ because _________________.

124 Lesson 6-3 Materials

125 Lesson 6-3

126 Changing the Surface Area L 6-3

127 Changing the Surface Area (summary) 6-3

128 L 6-3 The frictional force on an object moving across a surface does not depend on the base area of the object. Surface Area becomes a factor when the weight is increased.

129 Vocabulary – Lesson 6 The force that resists motion between two surfaces in contact with each other is (45) friction. When two objects are in contact and are rubbing against each other, they are producing (46) sliding friction. The size of the force is the (47) magnitude. L6

130 Vocabulary – Lesson 6 The force of friction does not change when the base area of an object in contact with a surface changes. The area in contact is called the (48) surface area. When the surface area changes, the force per unit area changes. This is known as changes in (49) pressure. L6

131 Vocabulary – Lesson 6 The result of forces between the stationary block and the surface area is (50) static friction. It takes a certain amount of force to overcome static friction and start the block moving (until the bonds between the block and the surface area are broken). The force needed to put the block in motion is greater than the force needed to keep the block moving. L6

132 Vocabulary – Lesson 6 An object at rest will remain at rest and an object in motion will move at constant speed in a straight line if no unbalanced forces act on it. This is known as (51) Newton’s First Law of Motion (law of inertia). For every action there is an equal and opposite reaction. This is known as (52) Newton’s Third Law of Motion. The speed at which an object is traveling in a single direction is (53) velocity. L6

133 Lesson 7

134 Lesson 7 - The Force Exerted by a Motor You will determine which combination of variables will produce the maximum force from an electric motor: connection of batteries, arrangement of string, and number of batteries.

135 Lesson 7

136 Question – Lesson 7 What are the conditions that produce the maximum force from a motor? What arrangement of string and batteries will allow the motor to produce the most force? Will the number of batteries affect the force of the motor? Will the arrangement of string, number of batteries, and arrangement of batteries affect the maximum force a motor will exert?

137 Lesson 7 If _________________,then __________ because _________________.

138 Lesson 7 Materials

139 Lesson 7

140 Diameter v. Number of Washers Lifted (Force) L 7

141 Arrangement and Number of Batteries v. Number of Washers Lifted (Force) Maximum force exerted by the motor: ______________________ L 7

142 The number and arrangement of batteries and the arrangement of string determines the performance of a motor: three batteries in series arrangement with the string around the nail pulley (smaller diameter).

143 Vocabulary – Lesson 7 A device that converts electrical energy to mechanical energy is a (54) motor. The motor exerted the most force when the string wound around the nail rather than the plastic pulley. This was because the plastic pulley was thicker than the nail. The thickness or width of an object is the (55) diameter. L7

144 Vocabulary – Lesson 7 When batteries are arranged with terminals connected from positive to negative to positive…, the arrangement is known as a (56) series connection. All electrons flow through a single path. Voltages combine. More current is produced. Energy is more rapidly delivered to the motor. It makes the motor more powerful. If one battery discharges, the circuit does not work.

145 Vocabulary – Lesson 7 When batteries are arranged with terminals connected from positive to positive and from negative to negative…, the arrangement is called a (57) parallel connection. There is more than one path for electrons to travel. Voltage is the same as a single battery. There is a small amount of current. Energy is transformed at a slower rate. Each battery lasts longer. If one battery runs down, the others continue to supply energy.

146 Vocabulary – Lesson 7 Several energy transformations take place in this lesson. Energy is stored in the bonds between atoms. This energy is known as (58) chemical energy. Chemical energy is transformed to energy that causes electrons to move. This is a transformation to (59) electrical energy. The flow of electrons is (60) electricity. Electrical energy is transformed into energy that runs the motor. This energy in moving objects is (61) mechanical energy. L7

147 Lesson 8

148 Lesson 8 - Work and the Motor You will learn the scientific meaning of work and will calculate work from examples given. You will calculate work done by an electric motor when it attempts to lift different loads of washers and a K’nex sled.

149 Work Work – when a force acts on an object and it moves some distance. WORK = Force (N) x Distance (m) L 8

150 WORK Alice pulls a sled with a force of 12 N. She pulls the sled through a distance of 5 m. How much work does Alice do on the sled? L 8

151 WORK Work = force x distance Work = 12 N x 5 m = 60 N-m L 8

152 WORK Michael lifts his book bag, which weighs 25 N, from the floor to a desktop that is 0.80 m above the floor. How much work does Michael do on the bag? L 8

153 WORK Force x Distance = WORK 25 N x 0.80 m = 20.0 N-m L 8

154 Inquiry 8.1 Calculating the Work Done on Different Surfaces L 8

155 1. What force are you working against when you lift a backpack? L 8.1b

156 2. In which of the following cases is work, as defined by scientists, being done? A. Someone tries to move a piano, but the piano won’t budge. L 8.1b

157 B. A tow truck is pulling a car slowly along the street. L8.1b

158 C. A student is studying for a mathematics exam. L 8-1b

159 D. A student is pushing a grocery cart around a store. L 8.1b

160 E. Another student is standing in line holding a 12-N bag of potatoes. L 8.1b

161 F. A student pushes against the school building. L 8.1b

162 Lesson 8

163 Question – Lesson 8 Is the motor capable of doing enough work to lift the sled to a distance of.10 m? What is the relationship between the force applied and the work that is done on the sled?

164 Lesson 8 If _________________,then __________ because _________________.

165 Lesson 8 Materials

166 Lesson 8

167 Lifting a Load 1. Motor force with three batteries in series: _________________ 2. Work done by a motor when it lifts a load 10.0 cm. (0.10 m) Work = _______ x _______ = ______ L 8-2

168 3. Weight of six washers:______________ 4.Work to raise six washers: Work = ______ x _______ = _______ 5. Your estimate of sled’s weight: _______ 6.Sled’s actual weight: _________ L 8-2

169 7.Work to lift sled 10.0 cm. (0.10 m): Work = _________ x ______ = _______ L 8-2

170 L8 Work is defined as the product of a force times the distance over which the force is applied. The unit of measure for work is the newton-meter or joule.

171 Vocabulary – Lesson 8 What happens when an object changes its position by moving in the direction of the force that is being applied is (62) work. Work = force x distance (w = fd) Work involves a force applied across a distance. The metric unit of work is the (63) newton-meter (N-m). A newton-meter is also a (64) joule (J). James Joule – described the relationship between work and energy. L8

172 Vocabulary – Lesson 8 A force is applied to lift the sled. This is the (65) effort force. The distance the sled moves is the (66) effort distance.

173 Vocabulary – Lesson 8 Electric current flows through the wire. The unit used to describe how much electric current flows through a wire is the (67) ampere (amp). Andre Ampere The electric potential of a battery is measured in (68) volts. Alessandra Volta

174 Lesson 9

175 Lesson 9 - Power of a Motor You will learn how to calculate the power in examples given. You will calculate the power of a motor with different number of batteries connected in series as it lifts a load of washers.

176 POWER POWER is the rate of doing work, or the amount of work done each second. POWER = WORK= (N-m) TIME s The common unit of power is the watt (W). 1 watt = 1 newton-meter second L 9

177 POWER A girl pushes on a box at a steady pace with a force of 8.0 N. She moves the box 3.0 m in 5.0 s. What is her power output? L 9

178 POWER Power = work = Newton-meter = watts timesecond 8.0 N x 3.0 m 5 s L 9

179 Lesson 9

180 Question – Lesson 9 Does the power of a motor change when more batteries are added in a series connection?

181 Lesson 9 If _________________,then __________ because _________________.

182 Lesson 9 Materials

183 Lesson 9

184 Number of Batteries and Time to Lift the Load L 9

185 Number of Batteries and Time to Lift the Load L 9

186 Lesson 9

187 Number of Batteries and Power of the Motor L 9

188 Lesson 9

189 L9 Power is the rate at which work is done. Power is calculated by dividing the work done by the time to do the work. The watt is the unit of measure for power. (one watt = one joule per second) Power increases when more batteries are added in a series connection.

190 Vocabulary – Lesson 9 The rate at which work is done is (69) power. work divided by time measure of the rate at which energy transformations take place The unit used to measure power is the (70) watt (w). 1 w = 1 joule per second James Watt L9

191 Lesson 10

192 Lesson 11

193 Lesson 11 - The Inclined Plane You will add wheels to the sled used in previous lessons. This cart will be pulled up an inclined plane at different angles while you measure the force required to pull the cart and the distance it moves along the inclined plane. You will also calculate the work to lift the cart a vertical distance of.10 m.

194 Lesson 11

195 Question – Lesson 11 How does the angle of an inclined plane affect the work done on an object? Why is the inclined plane a simple machine? L11

196 Lesson 11 If _________________,then __________ because _________________.

197 Lesson 11 Materials

198 Lesson 11

199 Work and the Inclined Plane Load force ________ x load distance _______ = ________ (work) (amount of work to lift cart.10 m)

200 Lesson 11

201 L11 The inclined plane reduces the effort force and increases the effort distance when doing work. The inclined plane does not change the amount of work that is done but it makes works easier to do because it decreases the effort force needed to do work. Frictional forces add to work.

202 Vocabulary – Lesson 11 The force applied to move an object, such as the cart, across a distance is (71) effort force. The distance an object moves to reach a certain point is (72) effort distance. The force needed to lift a load straight up is the (73) load force.

203 Vocabulary – Lesson 11 The vertical distance an object is lifted is (74) load distance. The angle of an incline is the (75) slope. A type of simple machine that increases effort distance and reduces effort force is an (76) inclined plane.

204 Lesson 12

205 Lesson 12 - The Pulley You will build different pulley systems and calculate the work done with each system to lift the sled a vertical distance of.10 m.

206 Lesson 12

207 Question – Lesson 12 How do pulleys affect the force exerted on an object? Why are pulleys simple machines?

208 Lesson 12 If _________________,then __________ because _________________.

209 Lesson 12 Materials

210 Lesson 12

211 Effort Force, Effort Distance, and Work in Pulley Systems Load force ________ x load distance_________ = ________ (work) (amount of work done to lift the sled and movable pulley system.10 m)

212 L20 A pulley reduces the effort force and increases the effort distance when doing work. A pulley makes work easier by reducing the effort force required to do work.

213 Vocabulary – Lesson 12 A simple machine that changes the magnitude and/or direction of the effort force required to do work is a (77) pulley.

214 Lesson 13

215 Lesson 13 - The Lever You will explore how to position washers to balance a load placed on the lever. You will calculate the work done in lifting the sled from different positions on the lever.

216 Inquiry 13.1 Left sideRight side # of washers # of holes from fulcrum # of washers # of holes from fulcrum

217 Lesson 13

218 Question – Lesson 13 How does the distance from the pivot point (fulcrum) affect the force required to lift an object?

219 Lesson 13 If _________________,then __________ because _________________.

220 Lesson 13 Materials

221 Lesson 13

222 Load force __________ x Load distance ________ = ___________ (work) Distance from center (# of holes) Effort DistanceEffort ForceWork The Lever

223 L13 A lever reduces effort force and increases effort distance when doing work. A lever makes work easier to do by reducing the effort force required to do work.

224 Vocabulary – Lesson 13 The fixed pivot point of a lever is the (78) fulcrum. A type of simple machine that uses a small force to lift a large load is a (79) lever.

225 Lesson 14

226 Ideal Mechanical Advantage effort distance load distance

227 Actual Mechanical Advantage load force effort force

228 Vocabulary – Lesson 14 The factor by which a machine multiples the effort force is (80) mechanical advantage. The ratio of effort distance to load distance when a machine does work is (81) ideal mechanical advantage. The ratio of load force to effort force needed to lift or move a load is (82) actual mechanical advantage. ACTUAL MECHANICAL ADVANTAGE IS LESS THAN IDEAL MECHANICAL ADVANTAGE BECAUSE OF FRICTION.

229 Lesson 15

230 Efficiency output work = load force x load distance x 100 input work effort force x effort distance

231 Vocabulary – Lesson 15 How much work that is put into a machine by its user is (83) work input. The work done by a machine against the resistance is (84) work output.

232 Lesson 16

233 Your mission, if you choose to accept it, is … Question: Can I lift the sled.1m using a motor? Hypothesis: If … Then… Because…. Hint: You may use up to 2 simple machines to perform the task. Be sure you write your procedures!!!

234 Lesson 17

235 Lesson 18

236 Lesson 18 - Motion of a Fan Car You will build a K’nex car and attach a fan to provide an energy source for the car. You will calculate speed at different intervals using time and distance measurements.

237 Lesson 18

238 Question – Lesson 18 How does the speed of a fan car change at.4 m intervals across a distance of 2 meters?

239 Lesson 18 If _________________,then __________ because _________________.

240 Lesson 18 Materials

241 Lesson 18

242 Time and Distance Data for the Fan Car L 18

243 Motion is a change in position. Speed is a measure of change in position over time. Unbalanced forces result in changes of motion. When forces are balanced, there is no change in motion. In the fan car, speed will increase until reaching a point where speed will remain relatively constant.

244 Vocabulary – Lesson 18 The rate at which an object changes its position over time is (85) speed. distance traveled time of travel When unbalanced forces act on an object, the object speeds up or slows down. This is (86) acceleration.

245 Vocabulary – Lesson 18 Newton’s three laws of motion –First law of motion – (inertia) – tendency of objects to maintain their motion when no forces act on them. –Second law of motion – Force = mass x acceleration –Third law of motion – for every action, there is an equal and opposite reaction. (Air blows in one direction, car goes in other direction).

246 Lesson 19

247 Lesson 19 - Motion of a Mousetrap Car You will measure the force exerted by a spring on a mousetrap. You will measure time and distance to determine the speed of the car at different intervals along a m. distance.

248 Lesson 19

249 Question – Lesson 19 How does the speed of a mousetrap car change at.4 m intervals across a distance of 2 to 4 meters?

250 Lesson 19 If _________________,then __________ because _________________.

251 Lesson 19 Materials

252 Lesson 19

253 Time and Distance Data for the Mousetrap Car L 19

254 Motion is a change in position. Speed is a measure of change in position over time. Unbalanced forces result in changes of motion. When forces are balanced, there is no change in motion. In the mousetrap car, speed will decrease after the initial push is exerted along a distance. Work is being done when the mousetrap is being set. Setting the mousetrap stores potential energy in the mousetrap. Releasing the mousetrap converts the potential energy to kinetic energy as the axle and wheels rotate.

255 Lesson 20

256 L 20

257 Lesson 21

258 Lesson 21 - Motion on a Roller Coaster You will learn about gravitational potential energy, potential energy, and kinetic energy as the roller coaster cars moves along the track. You will measure the speed of the car at different intervals along the track.

259 Lesson 21

260 Question What energy transformations take place as the roller coaster car travels along the roller coaster track? How does the speed of a roller coaster car change at different positions on the track? Where does a roller coaster car travel the fastest?... the slowest?

261 Lesson 21 If _________________,then __________ because _________________.

262 Lesson 21 Materials

263 Lesson 21

264 Speed of the Roller Coaster Interval / PositionDistance traveledTime of travelSpeed

265 L21 The position of an object determines gravitational potential energy. Potential energy can be converted to kinetic energy and kinetic energy can be converted to potential energy. Friction produces heat energy.

266 Vocabulary – Lesson 21 When the car is at the top of the track, it has stored energy. This is known as (87) potential energy. As the car moves along the track, it has (88) kinetic energy. When the car is at the highest point on the track, it has its’ largest amount of (89) gravitational potential energy.

267 Lesson 22


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