S8P2. Students will be familiar with the forms
and transformations of energy.
a. Explain energy transformation in terms of
the Law of Conservation of Energy.
The law of conservation of energy states
that:
• Energy is never destroyed
• Energy is never created
• Energy may be transformed or
converted from one form to another
• Energy is constantly changing forms
b. Explain the relationship between potential
and kinetic energy.
Kinetic Energy
• Energy of Motion
• Depends on
• Speed
• Mass
• More speed = more KE
• More mass = more KE
Potential Energy
• Energy of position (stored energy)
• Gravitational PE depends on
• Weight
• Height
• More weight = more PE
• More height = more PE
c. Compare and contrast the different forms
of energy (heat, light, electricity, mechanical
motion, sound) and their characteristics.
Forms of Energy:
Heat (thermal)—the vibration and movement
of the atoms and molecules within substances
ex. Atoms move faster in hot water vs. ice water
Light (radiant)—is electromagnetic energy
ex. Sunlight, X-rays,
microwaves, p.636
Electricity—energy of moving electrons,
typically moving through a wire
ex. lightening
Sound—energy caused by an object’s
vibrations
Mechanical Motion—is energy stored in a
moving object or an object that can move
PE + KE = mechanical energy
ex. Wind, Jack in the Box
Chemical—energy stored in the bonds of
atoms and molecules (is released during
chemical changes when atoms are rearranged)
ex. Cells in our body store chemical energy
Nuclear—energy stored in the nucleus of an
atom — the energy that
holds the nucleus together
ex. Nuclear power plants
http://www.eia.doe.gov/kids/energy.cfm?page=about_forms_of_energy-basics
http://www.bbc.co.uk/schools/ks2bitesize/science/physical_processes/
d. Describe how heat can be transferred
through matter by the collisions of atoms
(conduction) or through space (radiation). In a
liquid or gas, currents will facilitate the transfer
of heat (convection).
Conduction is the transfer of energy through
matter from particle to particle as they touch.
• Transfer of heat energy from atom to atom
• Most effective in solids.
• Heat moves from warmer substances to
cooler substances.
Convection
the transfer of thermal energy by the
movement of a gas or liquid (a medium).
The circular motion caused by density
differences that result from temperature
differences are called convection currents.
Radiation
• the transfer of thermal energy by
electromagnetic waves such as visible light
and infrared waves. (See p. 636-637).
• This energy can be transferred through
particles of matter OR empty space!
Examples
Energy from the sun
Microwaves use radiation
Review Questions
Which of the following converts electrical
energy into mechanical?
A light switch
B electric stove
C light bulb
D electric fan
According to the Law of Conservation of
Energy, if Sally throws a watermelon with 100
joules of energy off the roof of a building,
how much energy should the watermelon
have as it hits the ground?
A. 200 joules
C. 100 joules
B. 150 joules
D. 0 Joules
When a rock is thrown straight up into the air,
it reaches its highest point and briefly comes to
a complete stop before it starts to fall back to
the ground. Which is greatest at the point
where the rock stops?
A. potential energy
B. kinetic energy
C. force due to gravity
D. friction
A house becomes warm after air circulates
in the house. What type of heat transfer
happens?
a. Conduction
b. Convection
c. Radiation
Why do we insulate our soda cans?
a.To keep heat in
b.To keep heat out
c.To keep cold in
d.To keep cold out
Where is kinetic energy the greatest?
A
B
C
D
Where is potential energy the greatest?
A
B
C
D
Tonya drops a ball off a cliff as shown in the
picture. Which position shows where the ball
has the most kinetic energy and the least
potential energy?
A) A
B) B
C) C
Bob sat by the pool too long and his skin
began to burn. What type of heat transfer
occurred to make him burn?
a.Conduction
b.Convection
c.Radiation
At which position in the pendulum swing is
kinetic energy greatest?
a. A
b. B
c. C
d. D
At which position in the pendulum swing is
potential energy the lowest?
a. A
b. B
c. C
d. D
What type of heat transfer is
happening in the picture?
A. Heat to electrical
B. Chemical to mechanical
C. Mechanical to light
D. Heat to mechanical
What type of heat transfer is happening in the
air around the candle?
a.Conduction
b.Convection
c.Radiation
A gasoline-powered vehicle goes up a hill from
point X to point Y. What energy transformation
must occur in the car’s engine?
A Chemical energy into mechanical energy
B Electrical energy into light energy
C Electrical energy into sound energy
D Mechanical energy into light energy
When walking along an asphalt street after
sundown, a person often feels heat coming off
the pavement. The heat is moving from the
asphalt to the person by
A. Conduction
B. convection
C. Expansion
D. radiation
Heat, light, and electricity are all forms of
A. Atoms
B. energy
C. Cells
D. motion
The batteries in a flashlight make
electricity using
A. chemical
B. solar
C. heat
D. mechanical
In the pictures below, the candle is heating the
water in the tank. Which picture shows how the
water will move as it gets hot?
My dog, Ralph, wears slippers on hot days
because the pavement is hot on his feet.
What type of heat transfer makes his feet hot?
a. Conduction
b. Convection
c. Radiation
S8P3. Students will investigate relationship
between force, mass, and the motion of
objects.
a. Determine the relationship between
velocity and acceleration.
Velocity—
• the speed of an object in a particular
direction
• velocity must include speed (distance over
time) and direction!
• ex. an airplane travels west at 600 km/h
• if speed or direction changes the velocity
changes
Practice:
Tom is traveling west at 50 miles per hour.
Sally and her family are traveling south at 50
miles per hour. Do the cars have the same
velocity? Why or why not?
Tom
Sally
Acceleration—
• The rate at which velocity changes
• An object accelerates if its speed or
direction changes
• an increase in velocity is called positive
acceleration
• a decrease in velocity is called negative
acceleration or deceleration
• the faster the velocity changes, the greater
the acceleration
b. Demonstrate the effect of balanced and
unbalanced forces on an object in terms of
gravity, inertia, and friction.
Balanced Forces
• Occur when the forces on an object
produce a net force of 0 Newtons (N)
• Will not cause a change in the motion of a
moving object
• Will not cause a nonmoving
object to start moving
• ex. Hat on your head, bird’s nest
Unbalanced Forces
• Occur when the net force on an object is
not 0 Newtons (N)
• The forces are unbalanced
• Produce a change in motion
• Are necessary to start movement or
change movement
• ex. kicking a ball
Decide whether the following pictures
represent a balanced or unbalanced force
Gravity—
• A force of attraction between objects due
to their masses
• Law of Universal Gravity—all objects in the
universe attract each other through
gravitational force
+
Yes, you really are attracted
to your science book!
a. Recognize that every object exerts
gravitational force on every other object and
that the force exerted depends on how much
mass the objects have and how far apart they
are.
• Gravity decreases as distance increases.
• The more mass, the more
gravitational force
Inertia—
• The tendency of objects to resist any
changes in motion
• The more mass the more inertia
More mass more inertia
Less mass less inertia
Friction—
• A force that opposes motion between two
surfaces that are in contact
• Can cause a moving object to slow down
and eventually stop
• Caused by roughness of surfaces
c. Demonstrate the effect of simple machines
(lever, inclined plane, pulley, wedge, screw,
and wheel and axle) on work.
Inclined Plane—
• A flat slanted surface
• Less input force necessary, but must be
exerted over a longer distance
Examples: ramps, stairs,
Wedge—
• Device that is thick at one end and tapers
to a thin edge at the other end (two inclined
planes back to back)
• The longer and thinner the wedge, the less
input force is required (same as with the
inclined plane)
Examples: End of an ax, knife, zipper,
Push pin
Screw—
•An inclined plane wrapped around a cylinder
•The closer the threads, the greater the
mechanical advantage (longer distance, but
less input force needed)
Examples: Jar lid, bolts, faucets
The closer the
threads the greater
the mechanical
advantage
Wheel and Axle—
• Two circular objects fastened together that
rotate about a common axis
•The object with the larger diameter is the
wheel and the object with the smaller
diameter is the axle
• Multiplies your force, but you must exert
your force over a longer distance
Examples: door knobs, steering wheels, screw
drivers
wheel
axle
Levers—
•A rigid bar that pivots or rotates about a
fixed point called a fulcrum
3 different classes (types) of levers
1) 1st Class Levers—
•Fulcrum (pivot point) is located between
the input and output force (the load).
•Change the direction of the force (they can
also change size or distance of the force)
Examples: Seesaw, scissors, pliers, catapult
Effort
Effort
Fulcrum
Output/load
Fulcrum
Load
2nd Class Levers—
• The load is between the fulcrum and input
force (effort)
• Do not change the direction of the input force
• You must exert less force over more distance
Examples: Bottle openers, wheelbarrows
fulcrum
load
Input force
(effort)
3rd Class Levers—
•The input force (effort) is between the
fulcrum and the load
•Do not change the direction of the input force
•Does not multiply your input force (effort) but
allows you to apply a lot of force over a shorter
distance
Examples: Tweezers, Rake, baseball bat, Hammer
Remember FLE
1st Class– fulcrum in the middle
load
2nd Class– load is in the middle
Input force
(effort)
fulcrum
3rd Class– Effort (input force) is in the middle
Output/load
fulcrum
effort
Pulley—
•Grooved wheel with a rope
(or chain, or cable) wrapped around it
•Can change the amount and direction of
your input force
Fixed Pulleys—
•A pulley attached to a structure
•Does not change the amount of input force
•Changes the direction of the input force
Example: flag pole, sail boat, elevators
Moveable Pulley—
•A pulley attached to the object being moved
•Does not change the direction of the force
•Does increase your force—you use less force
over more distance
Example: a crane
Pulley System (Block and Tackle)—
•Combination of fixed and moveable pulleys
•Changes the size and direction of the force
you exert
Review Questions
Which characteristic of motion could change
without changing the velocity of an object?
A the speed
B the position
C the direction
D the acceleration
What two forces are responsible for keeping
Earth in orbit around the sun?
a.Gravity and friction
b.Gravity and inertia
c. Friction and inertia
d. Strong force and inertia
Which of the following represents the velocity
of a moving object?
A spring scale is pulled downward and
readings are recorded.
If the spring is pulled 3.5 cm, the spring scale
should read
A 12 N.
B 13 N.
C 14 N.
D 15 N.
A ball is dropped from the top of a tall building.
As the ball falls, the upward force of air
resistance becomes equal to the downward
pull of gravity. When these two forces become
equal in magnitude, the ball will
A flatten due to the forces.
B fall at a constant speed.
C continue to speed up.
D slow to a stop.
What is the net force on the cart above?
A 50 N.
B 150 N.
C 200 N.
D 350 N.
This box will increase in speed
A downward and to the left.
B downward and to the right.
C upward and to the left.
D upward and to the right.
When you bend your arm at the elbow, the
bones and muscles in your arm are acting as a
system. What simple machine does this
system represent?
A. inclined plane
B. pulley
C. Wedge
D. lever
Which simple machine is a pair of scissors?
A. wheel and axle
B. pulley
C. inclined plane
D. lever
On Earth, an astronaut has a mass of 140 kg.
When the astronaut goes into space, she
A.will have a mass of 140 kg, but will have
less weight.
B. will have less mass and weight.
C. will have a mass of 140 kg, and have a
weight of 140 kg.
D. will have less mass and a weight of 140
kg.
A person dives out of a nonmoving boat in
the direction indicated by Arrow A. Which
arrow shows the direction in which the boat
would move?
A. Arrow A
B. Arrow B
C. Arrow C
D. Arrow D
Which term refers to the rate of change of
motion?
A. Acceleration
B. speed
C. Momentum
D. velocity
The tendency for a body at rest to remain at
rest is known as
A. inertia
B. torque
C. momentum
D. mass
Where should Melissa position the fulcrum in
order to minimize the amount of force
needed to lift the box?
A. Point A
B. Point B
C. Point C
D. Point D
Which force causes a moving object to slow
and then stop?
A. Acceleration
B. inertia
C. Friction
D. lift
S8P4. Students will explore the wave nature
of sound and electromagnetic radiation.
a. Identify the characteristics of
electromagnetic and mechanical waves.
Electromagnetic Waves—
•Waves that do not
need a medium—a
substance through
which the wave can
travel
•All are transverse
waves
Mechanical Waves—
•Waves that need a
medium—a
substance through
which the wave can
travel
•Can be transverse or
longitudinal
Ex. light, microwaves,
Ex. sound waves,
TV &Radio waves, X-rays ocean waves
b. Describe how the behavior of light waves is
manipulated causing reflection, refraction
diffraction, and absorption.
Reflection—
• occurs when waves bounce off an object
• We see objects as different colors when that
color is reflected back at us
Ex.—A leaf appears green because it reflects
green light
Absorption–
•The transfer of energy carried by light to
particles of matter
•The farther light travels from its source the
more it is absorbed by particles (this is why
light becomes dimmer)
Refraction—
• The bending of a wave as it passes from one
medium to another
• Light travels slower through matter causing
light to bend
Diffraction—
• The bending of waves around barriers or
through openings
• Amount of diffraction depends on wavelength
and size of barrier or opening
• Wavelength of light is small so it cannot bend
very much
c. Explain how the human eye sees objects
and colors in terms of wavelengths.
• We see different wavelengths of visible light
as different colors
• Longest wavelengths are red
• Shortest wavelengths are violet
d. Describe how the behavior of waves is
affected by medium (such as air, water, solids).
Sound through media—
•Sound travels quickly though air
•Even faster through liquids
•Fastest through solids
Warmer objects will conduct sound faster
Why?
Particles move faster in warm object so they
transfer the sound faster
http://www.teachersdomain.org/asset/phy03_vid_zlistenstick/
http://egfl.net/Teaching/Resources/Animations/homepage.html
e. Relate the properties of sound to everyday
experiences.
Sound—
• a longitudinal wave caused by vibrations
and carried through a substance
• has to travel through a medium
Doppler Effect—
• Apparent change in the frequency of a
sound caused by the motion of the listener
or the source of the sound
• The sound will have a higher pitch as it
approaches
• Will have a lower pitch as it leaves
Echo—
•Reflected sound wave
•Occur when sound bounces off a flat hard
surface
f. Diagram the parts of the wave and explain
how the parts are affected by changes in
amplitude and pitch.
Parts of the wave—
Crest—the highest point of a transverse wave
Trough—the lowest point of a transverse wave
Wavelength—the distance from any point on
one wave to an identical point on the next wave
Amplitude—the maximum distance that the
particles of a wave vibrate from their rest
position
Crest
Rest Position
Trough
Amplitude
wavelength
Remember:
AL
Amplitude/loudness
PF
Pitch/Frequency
1) The amplitude of a wave is related to
height.
2) The greater the amplitude the louder the
sound and the more energy it has.
This wave will
sound loud
This wave will
sound quiet
Frequency—the number of waves produced
in a given amount of time
The frequency of a wave determines pitch.
A wave with a high frequency has a high
pitch.
A wave with a low frequency has a low pitch.
This wave would have a high pitch.
This wave would have a low pitch.
Review Questions
Which color reflects all colors of light?
A. black
B. white
C. green
D. red
When Marcia yelled from the top of a canyon,
an echo was created. This happened because
the sound waves of her voice bounced back
from the canyon walls. Which property of
waves occurred?
A. Diffraction
B. reflection
C. Interference
D. refraction
There is only one fish in the fishbowl below.
When Joseph looks down at the fish, the
image he observes is closer to the surface
than the actual location of the fish.
Which wave characteristic does Joseph’s
observation demonstrate?
A. amplitude
B. diffraction
C. reflection
D. refraction
Why are light-colored clothes cooler to wear in
the summer than dark-colored clothes?
A. Light-colored clothes let more air in.
B. Light-colored clothes prevent sweating.
C. Light colored clothes are not as heavy as
dark-colored clothes.
D. Light-colored clothes reflect more light than
dark-colored clothes.
A family is building an outdoor shower at
their cottage by hanging a plastic container
from a post, as shown above. The container
will be exposed to full sunlight. What color
should the container be to make the water as
warm as possible?
A. White
B. yellow
C. Black
D. red
In old movies, people sometimes put their ear
on a railroad track to see if a train is coming.
This works because the iron rail
A. is heated by friction
B. carries sound better than air
C. is cooler than air
D. is connected directly to the train
Sound A has a shorter wavelength than Sound
B. This means that Sound A will
A. be louder than Sound B.
B. be softer than Sound B.
C. have a lower pitch than Sound B.
D. have a higher pitch than Sound B.
Sound can travel fastest through
A. Air
B. metal
C. Water
D. outer space
A.
B.
C.
D.
Which wave has the highest frequency?
Which wave has the highest pitch?
Which wave has the softest sound?
Which wave has the loudest sound?
S8P5. Students will recognize characteristics
of gravity, electricity, and magnetism as
major kinds of forces acting in nature.
b. Demonstrate the advantages and
disadvantages of series and parallel circuits
and how they transfer energy.
Types of Circuits: Series and Parallel
Series Circuits—
•All parts of the circuit are connected in a
single loop
•Only one path for charges to follow
•All loads share the same current
Disadvantages
•Only one pathway for moving charges
•If there is a break in the circuit charges stop
flowing
(ex. if one light blows all the lights go out)
Advantages
•Burglar alarms use series circuits
Parallel Circuits—
•Loads are connected side by side
•Charges have more than one path on which
they can travel
•Loads do not have the same current (each
light will shine at full brightness)
• houses are wired in parallel
c. Investigate and explain that electric
currents and magnets can exert force on each
other.
Electric Current—
•The rate at which charges pass a given point
•Expressed in amperes (amps)
How an object becomes charged…
•If it loses electrons it becomes positively
charged
•If it gains electrons it becomes negatively
charged
Charged objects create electric force
•Greater the charge, the greater the force
•Closer the charges, the greater the force
Magnets•Anything that attracts iron or things made
of iron
•Have two poles (strongest attraction here)
•Exert force on each other (magnetic force)
•Surrounded by magnetic field
Electromagnetism—
•Interaction between electricity and
magnetism
• Electric currents produce a magnetic field
Review Questions
At which location is Earth’s
magnetic field the strongest?
A. 1
B. 2
C. 3
D. 4
In which circuit will the bulb light up?
A.
B.
C.
D.
Which best describes a parallel circuit?
A Electricity flows along one pathway.
B The flow of electricity comes from one source.
C Electricity flows along more than one
pathway.
D The flow of electricity comes from more than
one source
Three identical light bulbs are
connected in parallel with a battery, as
shown, and all are lit. If bulb I is
unscrewed and removed, what will
happen to the other two light bulbs?
A. Both will stay lit.
B. II will go out, but III will stay lit.
C. II will stay lit, but III will go out.
D. Both will go out.
The bulb in the electric circuit will NOT light
because
A. the switch is too far away from the bulb
B. the bulb has to be larger
C. the wires are not long enough
D. there is no energy source
Which electromagnet will pick up the most
paper clips?
A.
C.
B.
D.
Which diagram is a parallel circuit?
A.
B.
C.
D.