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Table of Contents
Page
Energy Transfer
Energy Transformations Reading
Law of Conservation Reading
Kinetic Energy Reading
Energy Questions
Recognizing KE & PE
Follow the Bouncing Ball Lab
PE & KE Problems - I
GPE and KE Math – II
PE and KE Problems III
Mr. Murray Conservation of Energy
5
6
7
9
10
11
15
18
21
23
Heat Energy
Movement of Heat Reading
Conduction Reading
Conduction Reading Questions
Convection Reading
Convection Questions
Radiation Reading
Radiation Questions
25
26
27
28
29
30
31
Comparing Insulating Materials
Conduction-Convection Lab
The Best Thermos Bottle Lab
Heat Transfer by Radiation
Review: Heat – A Form of Energy
33
35
37
39
41
Page
Electrical Energy
Electrical Energy and Circuits Reading
Electrical Energy and Circuits Questions
Electric Charge and Force
Series & Parallel Circuits Computer Lab
Electric Circuitry
Worksheet Series and Parallel
Series and Parallel Circuits – Explore
45
46
47
49
53
56
57
Magnetic Energy
Mr. Murray Magnetism Review
Electricity  Magnetism Lab
Generator Lab
Magnetic Resonance Imaging Reading
Electromagnet Pre-Lab
Electromagnetic Lab
Transformers
Energy Pamphlet
61
63
67
69
70
72
74
76
Page 3
Page 4
Page 5
Page 6
Page 7
Page 8
Energy Questions
Use the preceding reading pages to answer the following questions in complete
sentences.
1. What is potential energy?
2. What is kinetic energy?
3. What is the formula for gravitational potential energy?
4. How does elastic potential energy come into play?
5. What is the formula for kinetic energy?
6. What is mechanical energy?
7. Explain how energy changes form.
8. State the law of conservation of energy.
9. What is the difference between an open system and a closed system?
Page 9
Page 10
Follow the Bouncing Ball
Background:
Work is done raising a ball from the floor to a position above the floor. Once the ball
is raised from the floor, it has stored, or potential, energy. Potential energy becomes
kinetic energy, the energy of motion, as the ball drops to the floor. In this activity, you
will record observations and make predictions of how height balls will bounce when
dropped from different heights.
Hypothesis:
Materials: Meter stick
Balls (different masses, sizes and elasticity)
Graph paper
Procedure:
1. Work in teams of three. One team member holds the meter stick, one team
member drops the ball, and one team member makes the observations and records
the information.
2. Hold the meter stick vertically on a table or the floor with the zero end down.
3. Hold the ball so that the bottom is just opposite the 100 cm mark on the meter
stick.
4. Gently release the ball. Do not throw the ball down. This will add extra force,
making your data incorrect. Measure the height of the ball’s bottom at the highest
position it attains on the first bounce.
5. Drop the ball three times for each height.
6. Record your observations in the data table.
7. Make a graph of the average bounce height for each of the drop points of each
ball being studied. Show the average height bounced on the x-axis, and the height
from which the ball was dropped on the y-axis.
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Data Table:
_____________________ Ball
Height (in cm) from which the ball was dropped
Bounce
Height
100
90
80
70
60
50
40
30
20
10
Drop 1
Drop 2
Drop 3
Average
_____________________ Ball
Height (in cm) from which the ball was dropped
Bounce
Height
100
90
80
70
60
50
40
30
20
10
Drop 1
Drop 2
Drop 3
Average
_____________________ Ball
Height (in cm) from which the ball was dropped
Bounce
Height
100
90
80
70
60
50
40
30
20
10
Drop 1
Drop 2
Drop 3
Average
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Analysis:
1. What forces act on the ball as it falls?
2. Explain why none of the balls bounced back to its original drop point.
3. Explain why some balls bounce higher than other balls.
4. Predict the height a ball would bounce to if it were dropped from 125 cm.
5. Explain two ways you could test your prediction made in Question 4.
6. From what height would you drop a ball to make it bounce to the 100 cm mark?
Conclusion:
Summarize you experiment. Include an acceptance or rejection of your hypothesis.
Page 13
Page 14
Potential and Kinetic Energy Math – I
Potential energy is stored energy due to position. Kinetic energy is energy that depends
on mass and velocity (movement). Potential energy (PE) is mass x g x height or
PE = weight x height. PE is measured in units of Joules.
Formulas:
Potential energy = weight x height
Potential Energy
Weight 
height
Potential Energy
height 
weight
Abbreviations:
PE = wh
PE
w
h
PE
h
w
Units:
Joule (J)
Newtons
(N)
Meter (m)
Kinetic Energy is energy that is dependent on mass and velocity. In a closed system, the
sum of the potential energy and the kinetic energy is constant. As potential energy
decreases, the kinetic energy increases.
Formulas:
Kinetic Energy = ½ mass x velocity2
2 x Kinetic Energy
velocity 
mass
2 x Kinetic Energy
mass 
velocity 2
Abbreviations:
KE = ½ m x v2
2 x KE
v
m
2 x KE
m
v2
Units:
Joule (J)
Meters per second
(m/s)
Kilogram (kg)
NOTE: Whenever you are using the kinetic energy formula to find velocity you
must take the square root of V2 to find V (the last step of the formula).
1. Calculate the kinetic energy in joules of a 1500 kg car moving at the speed of
29 m/s.
Formula and Work
Set-Up
KE =
m=
v2 =
v=
ans. ______________________
Page 15
2. Calculate the gravitational potential energy in a car with a mass of 1200 kg at the
top of a 42 m high hill.
Formula and Work
Set-Up
PE =
m=
g=
h=
ans. ______________________
3. Calculate the GPE of a 65 kg climber on top of Mount Everest (8800 m high).
Formula and Work
Set-Up
PE =
m=
g=
h=
ans. ______________________
4. A 30 kg child has 190 J of kinetic energy after sledding down a hill. What is the
child’s speed in meters per second at the bottom of the hill?
Formula and Work
Set-Up
KE =
m=
v2 =
v=
ans. ______________________
Page 16
5. A bowling ball traveling at 2.0 m/s has 16 J of kinetic energy. What is the mass
of the bowling ball in kg?
Formula and Work
Set-Up
KE =
m=
v2 =
v=
ans. ______________________
Page 17
GPE and KE Math – II
Potential energy (PE) is stored energy due to position. Kinetic energy (KE) is energy
that depends on mass and velocity (movement). Potential energy (PE) is
PE = mass x g x height or PE = weight x height. PE is measured in units of Joules (J).
Formulas:
Potential energy = weight x height
Potential Energy
Weight 
height
Potential Energy
height 
weight
Abbreviations:
PE = wh
PE
w
h
PE
h
w
Units:
Joule (J)
Newtons
(N)
Meter (m)
Kinetic Energy is energy that is dependent on mass and velocity. In a closed system, the
sum of the potential energy and the kinetic energy is constant. As potential energy
decreases, the kinetic energy increases.
Formulas:
Kinetic Energy = ½ mass x velocity2
2 x Kinetic Energy
velocity 
mass
2 x Kinetic Energy
mass 
velocity 2
Abbreviations:
KE = ½ m x v2
2 x KE
v
m
2 x KE
m
v2
Units:
Joule (J)
Meters per second
(m/s)
Kilogram (kg)
NOTE: Whenever you are using the kinetic energy formula to find velocity you
must take the square root of v2 to find v (the last step of the formula).
1. A rock has a mass of 50 kg and is 10 m off the ground. What is the GPE of the
rock?
Formula and Work
Set-Up
PE =
m=
g=
h=
ans. ______________________
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2. The world record for pole vaulting is 6.15 m. If the pole vaulter’s GPE is 4942 J,
what is his mass?
Formula and Work
Set-Up
PE =
m=
g=
h=
ans. ______________________
3. A cheetah runs with a speed of 31 m/s. Suppose a cheetah with a mass of 47 kg runs at
this speed. What is the cheetah’s kinetic energy?
Formula and Work
Set-Up
KE =
m=
v2 =
v=
ans. ______________________
4. A diver has 3400 J of GPE after stepping up onto a diving platform that is 6.0 m above
the water. What is the divers mass in kilograms?
Formula and Work
Set-Up
PE =
m=
g=
h=
ans. ______________________
Page 19
5. A 35 kg child has 190 J of kinetic energy after sledding down a hill. What is the
child’s velocity in meters per second at the bottom of the hill? (take the square root of
v2).
Formula and Work
Set-Up
KE =
m=
v2 =
v=
ans. ______________________
6. A cat sits on the top of a fence that is 2.0 m high. The cat has a gravitational potential
energy of 88.9 J. What is the mass of the cat?
Formula and Work
Set-Up
PE =
m=
g=
h=
ans. ______________________
7. A tennis ball with a mass of 51 g has a velocity of 9.7 m/s upward. What is the kinetic
energy of the ball? (Note: you must convert g to kg before solving).
Formula and Work
Set-Up
KE =
m=
v2 =
v=
ans. ______________________
Page 20
Potential and Kinetic Energy-III
Potential energy is stored energy due to position. Kinetic energy is energy that depends
on mass and velocity (movement). Here is a review of the formulas:
Formulas:
Abbreviations:
Units:
Potential energy = weight x height
Kinetic Energy = ½ mass x velocity2
PE = wh
KE = ½ m x v2
Joule (J)
Joule (J)
Here is a review of the units used for the physics terms:
Physics Term
Units used to
Measure the Term
Abbreviation of Units
Energy (any type)
Weight
Height
Mass
Velocity
Joules
Newtons
meters
kilograms
meters per second
J
N
m
kg
m/s
For a closed system, the sum of the potential energy and the kinetic energy is a constant.
If the potential energy decreases, the kinetic energy increases. Also, if kinetic energy
decreases, the potential energy increases.
Solve the following problems:
1. What is the potential energy of a rock that weighs 100 newtons that is sitting on
top of a hill 300 meters high?
Ans: __________________________
2. What is the kinetic energy of a bicycle with a mass of 14 kg traveling at a velocity
of 3 m/s?
Ans: __________________________
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3. A flower pot weighing 3 newtons is sitting on a windowsill 30 meters from the
ground. Is the energy of the flower pot potential or kinetic? How many joules is
this?
Ans: __________________________
4. When the flower pot in Problem 3 is only 10 meters from the ground, what is the
potential energy?
Ans: __________________________
5. How much of the total energy in Problem 3 and 4 has been transformed to kinetic
energy as the pot hits the ground?
Ans: __________________________
6. A 1200 kg automobile is traveling at a velocity of 100 m/s. Is it energy potential
or kinetic? How much energy does it possess?
Ans: __________________________
Page 22
Page 23
Page 24
1. What is Heat?
2. How does Energy flow?
3. What does temperature measure?
Page 25
Page 26
Conduction Reading Questions
Using the preceding reading on conduction, answer the following questions in complete
sentences.
1. What is conduction?
2. Under what conditions does conduction occur?
3. Why does metal feel cool to the touch?
4. What is an insulator?
Page 27
Page 28
Convection Questions
Using the preceding reading, answer the following questions in complete sentences.
1. What is convection?
2. Explain how convection currents work?
3. How do convection currents keep Baytown cooler in the summer and warmer in
the winter?
4. Draw and label figure 18-1
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Page 30
Radiation
Using the preceding reading, answer the following questions in complete sentences.
1. What is radiant energy?
2. What is a unique characteristic of radiant energy?
3. How does radiant energy heat the air?
4. Give four examples of radiant energy.
Page 31
Page 32
Comparing Insulating Materials
A student is conducting an experiment with three different materials to determine
which material is the best insulator. The student fills a baker with 250 mL of boiling
water. Then she wraps a 2 cm thick layer of Insulator A around the beaker. The
student measures and records the temperature of the water every 30 minutes over a
period of 2 hours. She repeats this procedure with two other insulating materials,
Insulator B and Insulator C. The date obtained by the student is shown in the data
table. Use these data to answer the questions that follow.
Time (min)
Water Temperature ( °C)
Insulator A
Insulator B
Insulator C
0
100
100
100
30
88
96
92
60
75
93
85
90
63
88
76
120
50
85
68
1. Plot the data on a graph. Plot time in minutes on the horizontal axis
and water temperature in degrees Celsius on the vertical axis. Use
different colored pencils to connect the data points for each insulator.
2. Which material would make the best insulator? Explain your answer.
3. Why is a good insulator important for conserving energy in homes
during the winter? During the summer?
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Title: _______________________________________________________________
Page 34
Conduction-Convection Lab
Problem: How can you demonstrate convection and conduction by heating water in a
test tube with ice in it?
Background: Heat always travels from hot areas to cool areas. If objects of different
temperatures are brought together the warm objects will lose heat and the cooler objects
will gain heat until all of the objects are at the same temperature. Sometimes heat energy
is transferred by conduction, convection, or radiation. In this activity determine where
the ice and water is being heated by conduction and convection. Finally where is the
radiation taking place?
Hypothesis:
Materials: Test tube
Bunsen burner or large candles
Matches
Ice cubes
Procedure:
1. Drop a piece of ice into the test tube.
2. Fill the test tube nearly full with tap water.
3. Hold the test tube at the top with the tongs.
4. Heat the water from below, while the ice floats at the surface, by holding the
bottom of the test tube in the flame.
5. Observe what happens.
Questions:
1. Where is the water hottest, in the bottom or the top of the tube?
2. What method of energy transfer is heating the ice in the bottom of the tube?
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3. As the water is heated the density of the water changes. The warm water is less
dense. What does heating the water cause the water to do, rise or fall in the tube?
4. The movement of the warmer water into the cooler water is called convection or
conduction?
5. Though it is not happening in the test tube itself there is some heat transfer taking
place by radiation (through empty space). Where is radiation taking place?
6. How can you tell that water is a good insulator rather than a good conductor?
Page 36
The Best Thermos Bottle
The following experiment was performed with four thermos bottles to determine
which bottle would make the best thermos bottle.
Bottle A:
Bottle B:
Bottle C:
Bottle D:
Silvered, evacuated
Silvered, not evacuated
Not Silvered, evacuated
Not Silvered, not evacuated
Each bottle was filled with boiling water and the temperature of each bottle was taken
every 10 minutes at first and later at 20 to 30 minute intervals. The data obtained are
shown in the data table below.
Time
(min)
Temperature (°C)
Bottle A
Bottle B
Bottle C
Bottle D
0
100
100
100
100
10
100
99
97
95
20
99
95
94
91
30
99
91
91
86
40
98
88
88
83
60
97
83
82
75
90
96
74
75
67
120
95
67
68
60
150
64
61
65
56
1.
Plot the data on a graph using Time (min) as the horizontal axis and Drop in
Temperature (°C) as the vertical axis. Choose the scale of the vertical axis
carefully as it represents the drop in temperature for a given time. Use different
colored pencils or different symbols to draw the curves for each thermos bottle.
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2.
Which bottle would make the best thermos bottle? Why?
3.
Which bottle would be least effective as a thermos bottle? Why?
4.
Which of the two properties tested is the; more important in making a good
thermos bottle? Explain your answer.
Page 38
Heat Transfer by Radiation
Problem: How can you demonstrate convection currents and radiation using a light
bulb and extension cord?
Background:
The heating effect of the sun on the earth sets up huge convection currents in the
atmosphere. These air currents across the earth’s surface are called winds. Trade
winds and sea breezes are typical large-scale convection currents.
The process by which heat energy is transmitted through space is called radiation.
The energy of the sun comes to us by radiation. Most of the heat from wood burning
fireplaces escapes up the chimney by convection; the part that warms the room itself
is transmitted by radiation. Dark surfaces readily absorb radiation. If you place a
small dark-colored object on a block of ice in the sun, the object will slowly sink
through the object will slowly sink through the ice faster than the ice can melt. This
is because the object absorbs the suns radiation and the object becomes warm enough
to melt the ice underneath it. A dark colored coat is more practical in winter than
summer and a white shirt is more practical in summer than winter. The best emitter
of radiation is one with a dull black surface.
Hypothesis:
Material:
Light bulb
Extension cord
Lab sheet
Hands
Procedure:
1. Screw in the bulb into the extension cord.
2. Turn on the light.
3. Place your right hand above the lighted bulb and your left hand to the side or
below the bulb.
4. How does your right hand feel above the bulb as compared to your left hand?
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5. As the air around the bulb gets warmer, move your hand to different positions and
compare how this makes your hand feel.
Questions:
6. Why is the air above the light bulb warmer than the air to the side of the bulb?
(Explain this answer with the concept of density and convection in mind. Warm
air is less dense than cool air and this causes the air to move in a certain way).
7. What do we call a flow of heated air?
8. Draw a picture of your set-up and use arrows and labels to show where radiation
is taking place, how the air around the bulb is heated, and how the air around the
bulb moves in a convection current.
Page 40
Review:
Heat - A Form of Energy
Key Concepts
Heat is a form of energy caused
By the internal motion of
Molecules of matter.
Heat energy is transferred by
conduction, convection, and
Radiation.
Part I Building Vocabulary Skills
Decide which of the following statements correctly describes heat. If the statement
describes heat correctly, write H before the number. If the statement does not
describe heat correctly, write N.
_____ 1. Heat is an invisible, weightless fluid.
_____ 2. Heat is a substance called caloric.
_____ 3. Heat is made up of molecules.
_____ 4. Heat moves from a warmer object to a colder object.
_____ 5. Heat can be transferred in only one way.
_____ 6. Heat is a form of energy.
_____ 7. Heat is caused by the internal motion of molecules of matter.
_____ 8. Motion produces heat.
_____ 9. Cold molecules move faster than warm molecules.
_____10. The hotter a substance is, the less energy its molecules have.
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Part 2
Decide which of the following materials are conductors and which are insulators. If
the material is a conductor, write C before the number. If the material is an
insulator, write I.
______1. air
_____ 2. copper wire
_____ 3. rubber
_____ 4. glass
_____ 5. aluminum
_____ 6. silver
_____ 7. iron
_____ 8. wood
_____ 9. plastic
_____10. down
Heat Transfer: Understanding the Main Ideas
Identify the forms of heat transfer that take place in each illustration. Some illustrations
may show more than one form of heat transfer.
Page 42
Page 43
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Page 45
Electrical Energy and Circuits Questions
Answer the following questions in compete sentences.
1. What is electrical potential energy?
2. How do electric charged particles react?
3. What is potential difference?
4. How does current flow threw a flashlight?
5. What are the SI units for electric charge and current?
Page 46
Electric Charge and Force
Describe what happens between these pairs of subatomic particles using the terms
“attraction”, “repulsion,” or “nothing”. Place the correct term on the line provided
next to each figure.
Page 47
Make a drawing to show what will happen when each pair of particles comes together.
Remember that is some cases, nothing may happen.
1. A and C
2. B and E
3. C and D
4. A and D
5. E and F
6 B and D
Page 48
Series and Parallel Circuits
Computer Lab
Problem: How can you demonstrate the building of series and parallel circuits?
Background:
In a series circuit, elements are connected one after the other. This leaves the
electric current with only one path to follow. If the circuit is opened then the whole
circuit will shut down. Not a good thing for houses, schools, and businesses.
In a parallel circuit, the electric current has a least 2 paths to follow. If one of the
parallel connections is opened then the circuit will continue to work. This is the way
your home, school, and many businesses are wired to supply you with lights, TV, and
appliances.
Hypothesis:
Procedure:
A. Go to http://www.article19.com/shockwave/oz.htm and familiarize
yourself with the introduction page and what the symbols at the bottom
can do for you.
B. The most important symbols that you will use are the hand which will
allow you to go from exhibit to exhibit. The glasses, which enable you to
see the current direction. And the clear symbol which will clear your
board and allow you to start over or move to another exhibit.
Part I – Series Circuit
1. Click on the hand and request the lesson on how to build a series circuit.
2. In the series circuit, how are the elements connect?
3. What happens if you take one of the bulbs out of the circuit?
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4. Does current continue to flow or does current stop?
5. Draw a picture of the circuit that you are given in the explanation and label the
elements in the circuit. Be sure to show how the current is flowing.
6. Construct a series circuit that has one battery, a resistor, a switch, and a bulb. The
direction of the current should be to the right as you look at the circuit. Draw
your series circuit below.
7. Construct a series circuit that has a battery, 3 bulbs, 2 resistors, and a switch.
Current flow should be from right to left as current leaves the battery. What
happens when any element is removed from the circuit?
Page 50
Part II – Parallel Circuits
1. Click on the hand and choose the building a parallel circuit exhibit form the list.
Read the exhibit and answer the questions below.
2. How many paths in a parallel circuit are provided for the flow in a parallel
circuit?
3. What happens to one of the bulbs if one is removed from the circuit?
4. In a parallel circuit, if one of the bulbs goes out, then what will the other bulb do?
5. Is this a good way to wire a home, school, or business? Explain
6. Click the clear button and build the following circuits
a. Build a parallel circuit that has a battery, wire, and three bulbs each with
their own branch in the middle of the circuit. The current flow should be
from left to right. Draw a picture of your circuit, label the elements, and
show the current flow.
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b. Build a parallel circuit that has the following elements: a battery, 2
switches, wire, and three bulbs each on their own branch in the middle of
the circuit. The switches and wire are on the outside of the circuit. Draw
a picture of the circuit you made, label the elements, and show current
flow.
7. Click the clear button then click the hand and choose combination circuit.
8. Draw the combination circuit that is shown in this exhibit. Label the parts of the
circuit, show where the circuit is wired in series, and where the circuit is wired
parallel.
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1. Five parts of this circuit are not correct. Identify these parts by their letter and
explain why they are incorrect.
2. Change (A) so that the voltage source will work.
3. What must be done to complete the circuit?
For questions 4-8, assume that the electric circuit is complete
4. Which lamps will be lit?
5. Will electric bell (H) ring?
6. Will lamp (C) remain lit if lamp (E) is removed?
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7. Will lamp (I) be lit if lamp (C) is removed?
8. Will lamp (C) be lit if lamp (I) is removed?
9. Are lamps (I), (J), and (L) arranged in series or parallel?
10. How are lamps (C), (F), and electric bell (H) arranged?
1. According to the diagram, which bulbs will continue to light if
a. A blows out? ________________________________________________
b. B blows out? ________________________________________________
c. C blows out? ________________________________________________
d. D blows out? ________________________________________________
e. E blows out? ________________________________________________
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2. An object with a resistance of 15 ohms has a voltage of 45 volts applied to it:
a. How much electric current is going through this object?
_______________________________________________________________
b. How much power is being produced by the object?
_______________________________________________________________
c. How much electric energy will be needed to operate this object for 10
hours?
____________________________________________________________
d. What is the cost of operating this object for 10 hours at a rate of 8 cents
per kilowatt-hour? ____________________________________________
Page 55
Page 56
Series and Parallel Circuits – Explore
Problem:
How can you demonstrate a series circuit, combination circuit, and parallel circuit using
batteries, wire, switches, and a doorbell?
Background:
In a series circuit, the electrons can flow only in one direction and therefore the current is
the same at all points of the circuit no matter where a measurement is taken. If or any
reason one of the resistors in a series circuit is disconnected, the entire circuit shuts down
and no charges move.
In a parallel circuit, the resistors have their own separate paths for electric charges to
follow. In a parallel circuit, each branch will read the same voltage, but the current in the
individual branches can be different. If a branch of the circuit is opened the charges just
move into the other branches. For this reason, electrical circuits in houses, businesses,
schools, are wired in parallel. If one light or appliance goes out, the other will continue
to work.
Hypothesis:
Materials: 6 V dry cell battery
Small door bell
3 push button switches
Connector wires
Procedure:
1.
2.
3.
4.
Empty the packet which contains wires, switches, doorbell
Always clip the black wire to the battery.
Use color coated wires to complete your circuits
Be sure not to abuse the switches or wires because they are prone to
break easily.
Circuit I – Series Circuit
1.
2.
Arrange a dry cell, doorbell, and one button switch so that the circuit is in a
series.
Draw a diagram of your circuit.
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Circuit II – Combination Circuit Parallel and Series
3. Rearrange the circuit so that two switches can each ring the bell individually.
There must be one outer loop for the current to flow to the switches, through the
bell and return to the battery.
4. Draw the circuit diagram.
Circuit III – Parallel Circuit
5. Arrange the circuit so that it is truly parallel. The three switches should each have
their own path in the circuit and each is able to ring the bell by itself.
6. Draw a picture of your circuit below.
Page 58
Conclusion:
1. Explain the differences in a series and parallel circuit?
2. What is a combination circuit and when would you use one?
3. Why do public buildings use parallel circuits? Answer in complete sentences.
4. Summarize your experiment including acceptance or rejection of your hypothesis.
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Page 62
Electricity ↔ Magnetism
Electricity Creates Magnetism
Use the graph grid provided to plot the data on the chart below. Label the horizontal axis
“Number of coils of wire” and the vertical axis “Number of paper clips picked up.”
Electromagnet
A-10 coils
B-20 coils
C-30 coils
D-40 coils
E-50 coils
Number of paper clips Picked UP
3
6
10
13
17
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Page 64
Inducing a Current
Answer the following questions based on the accompanying diagram.
1. When the switch is first closed, what happens to the galvanometer needle?
2. When the switch is opened, is the galvanometer needle deflected in the same
direction?
3. If the connections on the dry cell are reversed, how would this affect the direction
of swing of the galvanometer needle?
4. What happens to the galvanometer needle when the switch remains in the same
position for several minutes? Why?
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Generator Lab
An electrical generator uses electromagnetic induction to convert
mechanical energy to electrical energy. In this activity you will see how an
electrical generator works to produce electricity from mechanical energy.
Go to http://www.walter-fendt.de/ph14e/generator_e.htm and work through
the lab.
1. This Java applet simulates a ____________________. Instead of an
armature with many windings of wire and iron nucleus there is only a
single rectangular conductor loop.
2. Find the radio buttons in the top right hand corner and choose the DC
generator. What does DC stand for? ______________. What does AC
stand for? _______________________. What does a DC generator have
that an AC generator does not?
3. The back arrows show the momentary direction of _____________.
4. Magnetic field lines (directed from the red painted north pole to the green
painted south pole) are colored ___________________________.
5. Red arrows represent the direction of the induced current, which is
(______________________________________________________).
6. Is the current produced in the red loop perpendicular or parallel to the
magnetic field?
7. Does the produced a maximum current or reduced current situation?
8. In this experiment you may do the following:
i. Change the direction of the current
ii. speed up or slow down the rotational speed
iii. pause and resume
9. With the communicator button pushed and the speed of rotation set at 6.0
rotation/min, read the voltmeter. In which direction does the voltmeter
register? Positive or Negative
10. In which direction does the coil turn? Left to right or right to left
11. Click the change of direction button
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12. Which way is the coil turning now? Left to right or right to left
13. Read the voltmeter. The needle is now registering towards the negative
side or the positive side.
14. Click the radio button-without communicator-the generator now changes
form a DC generator to a ___________________________________.
15. The AC generator does not have a _____________________________.
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Magnetic Resonance Imaging
Read the following paragraphs, and complete the exercises below.
Doctors who want information about a patient’s bones and joints, spine, or soft
tissues of the central nervous system, including the brain, often order a magnetic
resonance imaging (MRI) procedure. MRI uses computer technology, magnetic fields,
and radio waves to create an image of any part of the body. It is painless and does not
require instruments to enter the body.
MRI is possible because the magnetic behavior of hydrogen atoms, which are
abundant in the body. During the MRI procedure, a strong magnetic field is applied to
the patient’s body. The hydrogen atoms within the body respond to the magnetic field by
partly lining up with the field. Next, radio waves are directed at the atoms, causing some
of the atoms to flip over briefly. As the atoms flip back they give off radio waves. A
sensitive receiver picks up the radio waves, and a computer translates them into threedimensional map of the patient’s body.
Today’s MRI machines produce images with enough details to show the patient’s
body. The computer is able to show these images as across section of any part of the
body from any angle. The ability makes MRI even form powerful as a tool in medicine.
Exercises
1. What is the purpose of MRI?
2. What causes the hydrogen atoms to line up?
3. What action produces the radio waves that result in an MRI image?
4. An MRI instrument cannot be used on people with pacemakers, metal artificial
joints, or other metal implants. Explain why an MRI scan could be dangerous for
such a person.
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Electromagnet Pre-Lab
Problem: How does current and the number of coils affect the strength of the
magnetic field in an electromagnet?
Hypothesis:
Procedure:
1. Using a 16 penny nail and wire, make 5 loops of wire around the nail. Hook
one end of the wire up to the positive terminal and the other to the negative
terminal.
2. Scatter several paper clips within 10 cm of the nail.
3. Turn the voltage on ¼ of the way
4. Record the number of paper clips picked up
5. _____________________.
6. Repeat the procedure above, this time using twice the voltage.
7. Record the number of paper clips picked up
8. ____________________
9. This time follow the same procedure using full power
10. Record the number of clips picked up
11. ______________
12. For the remaining procedures the voltage will remain constant at ½ power but
the number of loops will change
13. 10 loops pick up how many clips?
14. ______________
15. 15 loops pick; up how many clips?
16. 20 loops pick up how many clips?
17. From your data collected, complete the following graphs
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Electromagnet Lab
Problem: After building a house, there are often many stray nails lying on the ground
of the construction site. You have been hired as foreman of the site to find an efficient
way to clean up the left over nails using an electromagnet.
Hypothesis:
Materials:
Procedure: (Part A)
Write a detailed step by step procedure. Describe each step so that another classmate
would be able to follow your directions. Use the number of coils listed in the data table.
Data Collection:
Table 1
# of Coils
5
10
15
20
# of “nails picked up
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Procedure: (Part B)
Using your final electromagnet with 20 coils, vary the voltage you are able to use.
Data Collection:
Table 2
Voltage
# of “nails” picked up
Conclusion:
As the foreman of the job, what configuration was the most efficient way to get your job
done? (Answer should be in paragraph form – a minimum of 5 content-related sentences.
Your answer should also relate efficiency to the number of coils and voltage).
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Transformers
Draw in the correct number of turns in the missing coil based on the voltage
given. Then identify the type of transformer using the following terms: step-up
transformers, step-down transformers, 1 to 1 transformer.
1. ___________________________
2. __________________________
3. ____________________________
The diagram below shows a transformer. Use the diagram to answer the questions
that follow.
4. What type of transformer is shown?
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5. If the voltage on the left is 400 volts, what is the voltage on the right?
6. If the voltage on the right is 80 volts, what is the voltage on the left?
7. What could be done to this transformer to increase the voltage produced on the
right?
8. Appliances in many countries run on electric current of 240 volts. Most small
appliances in the United States use 120 volts. Could this transformer be used to
adapt an American appliance to the voltage of a foreign country? Explain.
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ENERGY PAMPHLET
Objective: To create a brochure that describes the following:





Energy
Kinetic and Potential Energy (Mechanical Energy)
Work
Law of Conservation of Energy
Examples of Energy Conversions (heat, light, sound, mechanical,
electrical, chemical)
Directions: Trifold a piece of paper. Each will be for a specific section listed
above. Title your brochure and each section. List and define all
terms and formulas associated with each section. Illustrate and
give examples for each section.
Grading: 20 points for each section +20 points for illustrations/color
Due Date:
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