th
8
Science
Andrew Jackson
Lesson 1 –
Circuit of Inquiries –
A Preassessment
Inquiry 1.1
The Single Pulley
• Procedure
– Materials:
– 1.
– 2.
– 3……
• Inquiry 1.1
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
• 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
• Inquiry 1.3
•Conclusion
• Temperature increased due to friction.
Inquiry 1.4
Constructing a Graph
• Procedure
– Materials:
– 1.
– 2.
– 3……
• Inquiry 1.4
• Inquiry 1.4
•Conclusion
• The ball slowed down over time.
Inquiry 1.5
Transforming Energy
• Procedure
– Materials:
– 1.
– 2.
– 3……
• Inquiry 1.5
• 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
• 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
• 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
• 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
Lesson 2 - Making a Battery
You will build a zinc-copper battery cell and
observe the chemical reactions and
energy transformations that occur.
Lesson 2
Question
• How do you make a battery?
L2
• Lesson 2
• If _________________,then __________
because _________________.
• Lesson 2
•
•
•
•
Materials
1.
2.
3.
• Lesson 2
• Lesson 2
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.
• THREE MAIN COMPONENTS OF A
BATTERY
• Negative terminal – (zinc)
• Positive terminal – (copper)
• Electrolyte – copper sulfate
L2
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 oxidationreduction 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
• Battery-two metal electrodes in an
electrolyte that transfers chemical energy
into electrical energy.
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
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.
Lesson 3
Question – Lesson 3
• Do different devices use energy at
different rates?
• What evidence do we have that energy is
stored in a battery?
L3
• Lesson 3
• If _________________,then __________
because _________________.
• Lesson 3
•
•
•
•
Materials
1.
2.
3.
• Lesson 3
Light bulb v. motor
3 minute charging time
Lit time of bulb v. running time of motor
Light bulb
Motor
L3
• Different devices use energy at different
rates.
• Energy can be transformed from one form
to another.
• Energy can be stored in a battery.
• 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.”
L3
• 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 heat and light 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
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.
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
1.
2.
3.
• Lesson 4
Charging Time v. Lit Time
Grp
1
30
60
120
240
480
L4
Class Average: Time
Flashlight Stays On (s)
Time Flashlight Stays On (s)
Time Batteries are
Charged (s)
Grp
2
Grp
3
Grp
4
Grp
5
Grp
6
• Lesson 4
L4
• The amount of energy stored in a rechargeable
battery is proportional to the time the battery is
charged.
(See teacher manual)
(finish KWL)
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
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
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.
Lesson 5
Question – Lesson 5
• How is force and the elastic stretch of a
rubber band related?
• Lesson 5
• If _________________,then __________
because _________________.
• Lesson 5
•
•
•
•
Materials
1.
2.
3.
• Lesson 5
Elastic Force Created by
Stretching a Rubber Band
Stretching Distance
(cm.)
0.0
2.0
4.0
6.0
8.0
10.0
12.0
14.0
16.0
18.0
20.0
Elastic Force (N)
• Lesson 5
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.
L5
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.
L5
Weight v. Mass
Mass units
(number of
washers)
1
2
3
4
5
L5
L
6
Weight (N)
• Lesson 5
L5
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 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. This is known as
(44) Hooke’s Law.
Lesson 6
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.
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?
• How is pulling force related to the force of
friction?
• Lesson 6-1
• If _________________,then __________
because _________________.
• Lesson 6-1
•
•
•
•
Materials
1.
2.
3.
• Lesson 6-1
Force Needed to Move a Block
.27 m (27 cm.) Over Different Surfaces
Sliding Surface
Tabletop
Waxed Paper
Paper Towel
Fine Sandpaper
Coarse Sandpaper
L 6-1
Force (N)
Trial 1 Trial 2 Trial 3 Trial 4
Average
• Lesson 6
L 6-1
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.
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
1.
2.
3.
• Lesson 6-2
Force Needed to Move Two and Three Blocks
0.27 m (27 cm.) Over Different Surfaces
Sliding
Surface
Force (N)
AVG. Two
Two
Two AVG. Three Three Three AVG.
One blocks blocks blocks Two blocks blocks blocks Three
block Trial Trial Trial blocks Trial Trial Trial blocks
1
2
3
1
2
3
Tabletop
Waxed
Paper
Paper
Towel
Fine
Sandpaper
Coarse
Sandpaper
• Lesson 6-2
L 6-2
L 6-2
• The frictional force on an object moving
across a horizontal surface is directly
proportional to the weight of the moving
object.
Lesson 6-3
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 ?
• Lesson 6-3
• If _________________,then __________
because _________________.
• Lesson 6-3
•
•
•
•
Materials
1.
2.
3.
• Lesson 6-3
Changing the Surface Area
AREA
TABLETOP
COARSE
FINE
SANDPAPER SANDPAPER
WAXED
PAPER
PAPER
TOWEL
1 2 3 AV 1 2 3 AV 1 2 3 AV 1 2 3 AV 1 2 3 AV
Trial
FLAT
END
SIDE
L 6-3
Changing the Surface Area
(summary)
AREA
TABLETOP
FLAT
END
SIDE
6-3
COARSE
FINE
SANDPAPER SANDPAPER
WAXED
PAPER
PAPER
TOWEL
L 6-3
• The frictional force on an object moving
across a surface does not depend on the
base area of the object.
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
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.
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? 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?
• Lesson 7
• If _________________,then __________
because _________________.
• Lesson 7
•
•
•
•
Materials
1.
2.
3.
• Lesson 7
Diameter v. Number of
Washers Lifted (Force)
DIAMETER
Plastic pulley (large
diameter)
Nail (small diameter)
L7
NUMBER OF WASHERS LIFTED
( one battery)
Arrangement and Number of Batteries
v. Number of Washers Lifted (Force)
Number of
Batteries
Number of washers lifted
Series
Parallel
Arrangement
Arrangement
1
2
3
L7
Maximum force exerted by the motor: ______________________
L7
• 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).
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 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.
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
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.
Work
• Work – when a force acts on an object and
it moves some distance.
WORK = Force (N) x Distance (m)
L8
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?
L8
WORK
Work = force x distance
Work = 12 N x 5 m = 60 N-m
L8
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?
L8
WORK
Force x Distance = WORK
25 N x 0.80 m = 20.0 N-m
L8
Inquiry 8.1
Calculating the Work Done
on Different Surfaces
SURFACE
TABLETOP
WAXED
PAPER
PAPER
TOWEL
FINE
SANDPAPER
COARSE
SANDPAPER
L8
EFFORT
FORCE (N)
EFFORT
DISTANCE (m)
WORK DONE
(N-m)
• 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
• 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?
• Lesson 8
• If _________________,then __________
because _________________.
• Lesson 8
•
•
•
•
Materials
1.
2.
3.
• 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
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.
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
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.
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
L9
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?
L9
POWER
Power = work = Newton-meter = watts
time
second
8.0 N x 3.0 m
5s
L9
Lesson 9
Question – Lesson 9
• Does the power of a motor change when
more batteries are added in a series
connection?
• Lesson 9
• If _________________,then __________
because _________________.
• Lesson 9
•
•
•
•
Materials
1.
2.
3.
• Lesson 9
Number of Batteries
and Time to Lift the Load
NUMBER
OF
BATTERIES
1
2
3
L9
TIME 1
(s)
TIME 2
(s)
TIME 3
(s)
AVG. TIME
(s)
• Lesson 9
Number of Batteries
and Power of the Motor
Number
of
Batteries
1
2
3
L9
Force
(N)
Distance
(m)
WORK
(N-m)
TIME
(s)
POWER
(W)
• Lesson 9
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.
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
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.
Lesson 11
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
• Lesson 11
• If _________________,then __________
because _________________.
• Lesson 11
•
•
•
•
Materials
1.
2.
3.
• Lesson 11
Work and the Inclined Plane
Load force ________ x load distance _______ = ________ (work)
(amount of work to lift cart .10 m)
Hole
Number
6
8
12
16
20
Rise
(cm)
Run
(cm)
Slope
Effort
Force
(N)
Effort
Distance
(m)
Work
(N-m)
• Lesson 11
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.
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.
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
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.
Lesson 12
Question – Lesson 12
• How do pulleys affect the work done on an
object?
• Why are pulleys simple machines?
• Lesson 12
• If _________________,then __________
because _________________.
• Lesson 12
•
•
•
•
Materials
1.
2.
3.
• Lesson 12
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)
Type of
Pulley
System
Single fixed
Single fixed,
single
movable
Double
fixed, single
movable
Double
fixed, double
movable
Effort Force
(N)
Effort
Distance
(m)
Calculations
Work
(N-m)
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.
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
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.
Inquiry 13.1
Left side
# of
washers
# of holes from
fulcrum
Right side
# of
washers
# of holes from
fulcrum
Lesson 13
Question – Lesson 13
• How does the length of a lever affect the
work done on an object?
• Lesson 13
• If _________________,then __________
because _________________.
• Lesson 13
•
•
•
•
Materials
1.
2.
3.
• Lesson 13
The Lever
Load force __________ x Load distance ________ = ___________ (work)
Distance from
center
(# of holes)
Effort Distance
Effort Force
Work
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.
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
Ideal Mechanical Advantage
effort distance
load distance
Actual Mechanical Advantage
load force
effort force
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
Efficiency
output work = load force x load distance
input work
effort force x effort distance
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
Lesson 18
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.
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
1.
2.
3.
• Lesson 18
Time and Distance Data for the Fan Car
Distance Position
Interval
(m)
Time
(s)
Trial 1
1
0.0 - 0.4
2
0.4 – 0.8
3
0.8 – 1.2
4
1.2 – 1.6
5
L 18
1.6 – 2.0
Trial 2
Trial 3
Avg.
Speed
(m/s)
Average
L18
• 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.
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
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 2 4 m. distance.
Lesson 19
Question – Lesson 19
• How does the speed of a mousetrap car
change at .4 m intervals across a distance
of 2 to 4 meters?
• Lesson 19
• If _________________,then __________
because _________________.
• Lesson 19
•
•
•
•
Materials
1.
2.
3.
• Lesson 19
Time and Distance Data for the Mousetrap Car
Distance Position
Interval
(m)
Time
(s)
Trial 1
1
0.0 - 0.4
2
0.4 – 0.8
3
0.8 – 1.2
4
1.2 – 1.6
L 19
5
1.6 – 2.0
Trial 2
Trial 3
Avg.
Speed
(m/s)
Average
L19
•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.
Lesson 20
L 20
Lesson 21
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.
Lesson 21
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?
• Lesson 21
• If _________________,then __________
because _________________.
• Lesson 21
•
•
•
•
Materials
1.
2.
3.
• Lesson 21
Speed of the Roller Coaster
Interval / Position
Distance traveled
Time of travel
Speed
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.
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