8 th Science

Lesson 1 – Circuit of Inquiries – A Preassessment

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

Inquiry 1.1

Conclusion A pulley changes the direction of a force.

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

Inquiry 1.2

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

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

Inquiry 1.3

Conclusion Temperature increased due to friction.

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

Inquiry 1.4

Conclusion The ball slowed down over time.

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

Inquiry 1.5

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

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

Inquiry 1.6

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

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

Inquiry 1.7

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.

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

Inquiry 1.8

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

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.

Lesson 2

Can I make a battery? How can I make a battery using the materials given? Can I make a battery that will work? How do you make a battery? L 2

Lesson 2 If _________________,then __________ because _________________.

Lesson 2 Materials

Lesson 2

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

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

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

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

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

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

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

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

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

Lesson 3

Which uses the most energy, a light bulb or an electric motor? Does a bulb or a motor use the most energy? Is there a difference in the amount of energy needed by a battery and a motor? Do different devices use different amounts of energy? L3

Lesson 3 If _________________,then __________ because _________________.

Lesson 3 Materials

Lesson 3

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

Lesson 3

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

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

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 light and heat in the bulb. L3

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

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.

Lesson 4

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?

Lesson 4 If _________________,then __________ because _________________.

Lesson 4 Materials

Lesson 4

Charging Time v. Lit Time L4

Lesson 4

Vocabulary – Lesson 4 The stored chemical energy is the battery is changed to electrical energy and light and heat 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

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

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

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

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.

Lesson 5

Question – Lesson 5 What is the relationship between force, mass, and weight? How is force and the stretch of a rubber band related? How do you measure elastic force?

Lesson 5 If _________________,then __________ because _________________.

Lesson 5 Materials

Lesson 5

Elastic Force Created by Stretching a Rubber Band

Lesson 5

L 5

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

Weight v. Mass L L 5

Lesson 5 L 5

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

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

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 (“stuff”) 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

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

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.

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 is (44) Hooke’s Law.

Lesson 6

Lesson 6-1

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

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

Lesson 6-1 Materials

Lesson 6-1

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

Lesson 6 L 6-1

Lesson 6-1

Lesson 6-2

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?

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

Lesson 6-2 Materials

Lesson 6-2

Force Needed to Move Two and Three Blocks 0.27 m (27 cm.) Over Different Surfaces L 6-2

Lesson 6-2 L 6-2

Lesson 6-2

Lesson 6-3

Question 6.3 Does changing the surface areas in contact change the amount of friction? Does surface area affect friction? How is surface area and friction related?

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

Lesson 6-3 Materials

Lesson 6-3

Changing the Surface Area L 6-3

Changing the Surface Area (summary) 6-3

Lesson 6-3

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

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

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

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

Lesson 7

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?

Lesson 7 If _________________,then __________ because _________________.

Lesson 7 Materials

Lesson 7

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

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

Lesson 7

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

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.

Vocabulary – Lesson 7 When batteries are arranged with terminals connected from positive to positive or 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.

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

Lesson 8

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

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

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

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

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

Inquiry 8.1 Calculating the Work Done on Different Surfaces L 8

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

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

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

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

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

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

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

Lesson 8

Question – Lesson 8 How do you calculate work? What is the relationship between force applied and the work that is done? How much work is required to lift a load? How do you measure the work to lift a load?

Lesson 8 If _________________,then __________ because _________________.

Lesson 8 Materials

Lesson 8

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

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

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

Lesson 8

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

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.

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

Lesson 9

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

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

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

Lesson 9

Question – Lesson 9 How do you calculate the power of a motor?

Lesson 9 If _________________,then __________ because _________________.

Lesson 9 Materials

Lesson 9

Number of Batteries and Time to Lift the Load L 9

Lesson 9

Number of Batteries and Power of the Motor L 9

Lesson 9

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

Lesson 10

Lesson 11

Question – Lesson 11 What purpose does an inclined plane serve? How does an inclined plane affect work? What is an inclined plane? How is an inclined plane used? For what is an inclined plane used? L11

Lesson 11 If _________________,then __________ because _________________.

Lesson 11 Materials

Lesson 11

Work and the Inclined Plane L 11

Lesson 11

Vocabulary – Lesson 11 The force applied to move an object, like 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.

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.

Lesson 12

Question – Lesson 12 What is the purpose of a pulley? How does a pulley affect the amount of work done on an object?

Lesson 12 If _________________,then __________ because _________________.

Lesson 12 Materials

Lesson 12

Effort Force, Effort Distance, and Work in Pulley Systems L 12

Lesson 12

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.

Lesson 13 T

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

Question – Lesson 13 How does a lever affect work? How does a lever work? What is the purpose of a lever?

Lesson 13 If _________________,then __________ because _________________.

Lesson 13 Materials

Lesson 13

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.

Lesson 14

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.

Lesson 15

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.

Lesson 16

Lesson 17

Lesson 18 T

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

Lesson 18 If _________________,then __________ because _________________.

Lesson 18 Materials

Lesson 18

Time and Distance Data for the Fan Car L 18

Lesson 18

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.

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).

Lesson 19

If _________________,then __________ because _________________.

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

Lesson 19 Materials

Lesson 19

Time and Distance Data for the Mousetrap Car L 19

Lesson 19

Lesson 20

L 20

Lesson 21

If _________________,then __________ because _________________.

Lesson 21 Materials

Lesson 21

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.

Lesson 22