UNIT 2: ENERGY
Physical Science
Hobbs
Bell Ringer: Friday, August 29, 2014
Calculate the speed for a car
that went a distance of 125
kilometers in 2 hours time.

The Nature of Energy
-Energy is the ability to do work. When
work is done, energy is transformed or
transferred.
 -The SI unit of energy is the joule (J)…
the same as the unit for work.

Potential and Kinetic
Stored
energy is called potential
energy
The energy of motion is called
kinetic energy
Potential Energy/Gravitational
Potential Energy
-Potential energy may be stored in
chemical bonds or due to the
“position” of the object.
-The energy of position is called
“gravitational potential energy.”

Kinetic
Which picture shows balloons with
high kinetic energy?
Potential vs. Kinetic
At letter “W” does the roller coaster car have high
potential energy or high kinetic energy?
Potential vs. Kinetic
At letter “X” does the roller coaster car have
high potential energy or high kinetic
energy?
Potential vs. Kinetic

When Katniss is
aiming her arrow
at the deer, what
kind of energy
does the arrow
have?
Energy Transfer
Potential
Energy
Energy Transfer
Kinetic Energy
GPE - Practice

Calculate the GPE in the following systems:
A
car with a mass of 1200kg at the top of a 42m
high hill
 GPE = mass x gravitational constant x height
 GPE = 1200kg x 9.8 m/s2 x 42m = 4.9 x 105 J
 Make sure mass is in kg and distance is in
meters.
GPE - Modeled

A 2.3kg ball rolls 14 meters. How much
gravitational potential energy does it posses?
GPE - Modeled

A 40kg object is lifted to a height of 50 meters.
What is the GPE of the object?
Kinetic Energy
-The square applies only to the velocity;
therefore, KE depends more on the
speed or velocity than the mass.
 -Anything that has mass and motion
will have kinetic energy; so, something
as small as an atom will have KE.

Kinetic Energy
-Kinetic Energy is the energy of
motion.
-Kinetic Energy = ½ mass x
velocity2

KE
= ½ m x v2
KE – Practice Problems

-Calculate the kinetic energy of a
1500kg car moving at the following
speed 18 m/s
= ½ (1500kg) x (18m/s)2 = 2.4 x 105J
*Make sure the mass is in kg and the speed
is in m/s*
KE
KE- Modeled

A 2kg chair is thrown with a velocity of 8 m/s.
What is the kinetic energy of the chair?
KE - Modeled

What is the kinetic energy of a 89kg object moving
at 26 m/s?
KE –
A 7kg rock is thrown with a velocity
of 12 m/s. What is the kinetic
energy of the rock?
 What is the kinetic energy of a 62kg
object moving at 23 m/s?

Potential and Kinetic: Review Activity
1.
2.
Find at least 3 pictures for each
(potential and kinetic) in the
magazines
With the pictures you chose
explain how each is either kinetic
or potential.
Mechanical Energy

Mechanical energy is a “large-scale”
combination of the kinetic and potential energy
within a system; this is the type of energy we
usually think of
 Ex:
The intercom falling from the wall is a form of
mechanical energy, combining both GPE (height)
and KE (speed)
Extension Activity
1.
2.
3.
4.
5.
http://phet.colorado.edu/en/simulation/ener
gy-skate-park-basics
Click run now
Open up bar graph and pie chart
If you change the skater’s mass what happens
to the energy?
Design a skate park using the concepts of
mechanical energy and energy conservation.
3. Bell Ringer: Tuesday, September 2,
2014

The mass of a
2013 Chevy
Silverado crew cab
is 4850 kg. If it
was traveling
down the highway
at 85km/h, what is
the total kinetic
energy of the
vehicle?
Potential Energy

A 56kg object is lifted to a height of 16 meters.
What is the potential energy of this object?
Potential Energy

A 15kg squirrel climbs 12m up a tree. When he
stops, what is the squirrel’s potential energy?
Kinetic Energy

What is the kinetic energy of a 96kg object moving
36 m/sec?
Kinetic Energy

The kinetic energy of a truck is calculated at
96,000J. If the truck has a mass of 50,000kg, with
what velocity is it moving?
Kinetic and Potential Energy Problems
#7 and #10
change N to kg

Forms of Energy Foldable
1.
2.
3.
Fold piece of paper hot dog style
7 Sections for 7 forms of energy
Each section should have:
1.
2.
3.


Form of energy
The definition
An example of that form of energy
On the back make two lists one for POTENTIAL and one for
KINETIC, the forms of energy should go under a type they
cannot be both.
MECHANICAL, RADIANT, THERMAL, NUCLEAR, CHEMICAL,
SOUND, ELECTRICAL
4.
Law of Conservation of Energy
•
•
•
•
Conservation of energy – does not mean
saving energy
The law of conservation of energy says that
energy is neither created nor destroyed.
So when we use energy it doesn’t disappear.
We change it from one form of energy into
another.
4. Bell Ringer: Wednesday,
09/03/2014
What is the kinetic energy of a 1000 kg car
traveling at 20 m/s _______.
 a. 200,000 J
 b. 20,000 J
 c. 400,000 J
 d. 20,000,000 J

Potential Energy: Mechanical
•
•
•
Energy stored in objects
by tension.
Compressed springs
and stretched rubber
bands are examples of
stored mechanical
energy.
Combination of KE + PE
Kinetic Energy: Radiant
•
•
•
•
Electromagnetic energy that
travels in transverse waves.
Radiant energy includes
visible light, x-rays, gamma
rays and radio waves.
Light is one type of radiant
energy.
Sunshine is radiant energy,
which provides the fuel and
warmth that make life on
Earth possible.
Kinetic Energy: Thermal
•
•
•
Thermal energy, or heat, is
the vibration and movement
of the atoms and molecules
within substances.
As an object is heated up,
its atoms and molecules
move and collide faster.
Geothermal energy is the
thermal energy in the Earth.
Potential Energy: Nuclear
•
•
•
•
Energy stored in the nucleus of
an atom — the energy that
holds the nucleus together.
Very large amounts of energy
can be released when the
nuclei are combined or split
apart.
Nuclear power plants split the
nuclei of uranium atoms in a
process called fission.
The sun combines the nuclei of
hydrogen atoms in a process
called fusion.
Potential Energy : Chemical
•
•
•
•
Chemical energy is
stored in the bonds of
molecules.
This is a form of
potential energy until the
bonds are broken.
Fossil fuels and biomass
store chemical energy.
Products that contain
chemical energy include:
TNT, baking soda, and a
match.
Kinetic Energy: Sound
•
•
•
Sound is the movement of
energy through substances in
longitudinal
(compression/rarefaction)
waves.
Sound is produced when a
force causes an object or
substance to vibrate — the
energy is transferred through
the substance in a wave.
Typically, the energy in sound
is far less than other forms of
energy.
Kinetic Energy: Electrical
•
•
Electrical energy is
delivered by tiny
charged particles
called electrons,
typically moving
through a wire.
Lightning is an example
of electrical energy in
nature, so powerful that
it is not confined to a
wire.
Potential Energy: Gravitational
•
•
•
•
Gravitational energy is energy
stored in an object's height.
The higher and heavier the
object, the more gravitational
energy is stored.
When you ride a bicycle down a
steep hill and pick up speed, the
gravitational energy is being
converted to motion energy.
Hydropower is another example
of gravitational energy, where
the dam "piles" up water from a
river into a reservoir.
Kinetic Energy: Motion
•
•
•
•
•
Energy stored in the movement
of objects.
The faster they move, the more
energy is stored.
It takes energy to get an object
moving, and energy is released
when an object slows down.
Wind is an example of motion
energy.
A dramatic example of motion
is a car crash, when the car
comes to a total stop and
releases all its motion energy at
once in an uncontrolled instant.
Energy Transformations within a System
Energy Transformations within a System
Energy Transformations within a System
Energy Transformations within a System
Summarizer

Half Sheet of paper

What are the energy transformations within this system?
Review: Energy transformations

What does the law of
conservation of energy state?
Review: Energy Forms
Review: energy forms
Review: energy forms
Review: energy forms
Review: energy Forms
Review: Energy Trans in a System
REVIEW: Energy Trans in a System
REVIEW: energy trans in a system
5. Bell Ringer: Thursday, 09.04.14

Name the types of energy IN ORDER that flow
within this system.
Heat Transfer
-Vocabulary sheet
 -you need four different colors

-if you do not have three different colors, you will draw
three different shapes with your pencil/pen
 -Draw squares around the following key words:
 Heat Transfer
 Conduction
 Convection
 Radiation

conduction
rays or waves
radiates
high temperature
bump
fluid
vents
low temperature
contact
radiation
solid
heat transfer
convection
flows
Heat Transfer
Linking the underlined words in the
same color, you may write notes on
the lines between key words.
Heat Transfer

Thermal energy transfer is movement of
thermal energy from an area of high
temperature to an area of low
temperature
Heat Transfer
Heat Transfer: Conduction
Transfer of heat that happens when molecules
bump into each other, usually solid object
 Conduction=CONTACT

Have you ever?

Touched a metal spoon sitting in a cup of hot
coffee? What happened?
Think back to what you know about metals and nonmetals.
What conducts heat better, metal or nonmetal? Why?
Heat Transfer: Conduction




In that cup of hot water with the spoon, the following is happening:
The fast-moving particles of the coffee come in contact with the slowmoving particles of the cool metal spoon.
Then the slower particles in the metal spoon begin to move faster and heat
is being transferred.
As the particles move faster, the metal spoon gets hotter. This process is
repeated until the entire spoon is hot.
EXAMPLE OF CONDUCTION

An ice cube in your hand (contact)
Heat Transfer: Convection
•
•
•
Transfer of heat by the flow of fluids
(liquids and gases)
Convection = VENTS
Convection has a circular
pattern
Have you ever?

Noticed that the air near the ceiling is warmer than the
air near the floor? Why do you think this happens?


Warm air is less dense and rises
Cold air is more dense and sinks
Heat Transfer: Convection
•
•
•
•
•
When the water at the bottom of a pot is heated, its
particles move faster, and they also move farther
apart.
The heated water becomes less dense.
Therefore, the heated water rises in the pot.
The cooler water at the top of the pot sinks.
The movement of the fluids creates a circular motion
of particles called convection currents
EXAMPLE OF CONVECTION

A radiator (vent)
Heat Transfer: Radiation



Heat is Transferred in rays or waves
Matter is not required to transfer thermal energy
Radiation = Radiates
Have you ever…

Place your hand really close to a light bulb that was
turned on? What did you feel?
Heat Transfer: Radiation



All objects radiate energy and heat, even your own
body.
However, the radiation coming from hotter objects is
more intense than that coming from cooler objects.
The hotter an object, the shorter the wavelength of
this radiation.
EXAMPLE OF RADIATION

Fire (radiates)
Conduction, Convection, or Radiation
Conduction, Convection, or Radiation
Review

What state does the following occur?
Particles
are in fixed a regular
arrangement
Review


In which states?
Are the particles randomly arranged and free to
move?
REVIEW

Which sort of heat transfer…

Does not require particles?
REVIEW

Give an example of where convection currents
can occur…
Summarizer: 3-2-1
HALF SLIP OF PAPER
Three things you learned today
 Two things you kind of understand, but may still
be unsure of
 One thing know you need to do better in this
class.

Bell Ringer: Wednesday, 02.12.14





A heat source is located under one end of a solid material.
What process, represented in the illustration, carries heat to
the other end of the block?
A. convection
B. radiation
C. conduction
D. none of the above
KE

The mass of a 2013 BMW i8 is 5650 kg. If it was
traveling down the highway at 85km/h, what is the
total kinetic energy of the vehicle?
KE

What is the mass of a cart that has a
kinetic energy of 5,554 J and a
speed of 10.98m/s?
KE

A 250g Nerf dart is shot from Saxon’s Nerf
gun with a kinetic energy of 4.4J. What is
the initial speed of the dart?
PE

A ball is at the top of a 40 m ramp. It has
a mass of 20 kg. What is the ball’s GPE?
PE

A box with a mass of 12.5 sits on the
floor. How high would you need to lift it for it
to have a GPE of 355 J ?
PE

A marble is on a table 2.4 m above the
ground. What is the mass of the marble if it
has a gravitational potential energy of 568 J.
Review
HEAT TRANSFER
Heat Transfer: Conduction
What are the key words?
 Conduction is….

Heat Transfer: Convection
Heat Transfer: Radiation
Reading Essentials (BLUE BOOK)

Chapter 6: Section 2
 THERMAL
ENERGY, USING HEAT on your own
paper
 Answer
questions on the sides under
headings (Identify definitions, reading
checks, think it over, picture this) and the
questions in the section “AFTER YOU
READ”
Bell Ringer: Thursday, 02.13.14
What are the energy transformations
within these systems (in order)?
Bell Ringer: Tuesday, 02/18/2014

Name examples of each:
Conduction
Convection
Radiation
Specific Heat Capacity


Specific Heat Capacity can
be thought of as a measure
of how much heat energy
is needed to warm the
substance up.
You will possibly have
noticed that it is easier to
warm up a saucepan full of
oil than it is to warm up
one full of water.
Specific heat capacity: SHC

Specific Heat Capacity (C) of a substance is the
amount of heat required to raise the temperature of
1g of the substance by 1oC (or by 1 K).
SHC

The next table shows how much energy it takes to
heat up some different substances.

The small values show that not a lot of energy is
needed to produce a temperature change, whereas
the large values indicate a lot more energy is
needed.
SHC: The Equation
The amount of heat energy (q) gained or lost by
a substance = mass of substance (m) X specific
heat capacity (C) X change in temperature
(ΔT)
q = m x C x ΔT
SHC
Explanation:
The change in temperature (ΔT) is:
75ºC - 25ºC = 50ºC
Given mass, two temperatures, and a specific heat capacity,
you have enough values to plug into the specific heat
equation
q = m x C x ΔT
and plugging in your values you get
q = (450 g) x (0.385 J/g ºC) x (50.0ºC)
= 8700 J
SHC: Effect of Mass on heat
Large object

Smaller object
mcΔT
Q is bigger

= mcΔT


=
Q is smaller
Conclusion: bigger objects need more energy to raise their temperature
SHC: EFFECT of SHC on HEAT

Large Specific Heat

= m ΔT

c
Q is bigger

Smaller Specific Heat

= mcΔT
Q is smaller
4.18 J/g·°C
0.32 J/g·°C
Conclusion: bigger SHC need more energy to raise their temperature by the same
amount
SHC: Effect of Temp CHG on HEAT

Large Temp Change

= mc

ΔT
Q is bigger

Smaller Temp change

= mcΔT
Q is smaller
Conclusion: bigger SHC need more energy to raise their temperature by the
same amount
7. Bell Ringer: Monday, 09.08.2014


A 10.0 kg block of lead is heated in the Sun from
25.0ºC to 30.0ºC. Use the table to help calculate
the change in the block's thermal energy?
A. 900 J
B. 1300 J
C. 6450 J D. 3900 J
SHC: Guided
How much heat is required to raise
the temperature of 180.0 g of
mercury by 52°C?
(specific heat for mercury is 0.140
J/g°C)

SHC
How much energy would be needed to
heat 250 grams of copper metal from a
temperature of 10.0ºC to a temperature
of 35.0ºC?
(The specific heat of copper at 10.0ºC is
0.385 J/g ºC.)
SHC

Calculate the amount of heat needed to
increase the temperature of 150g of
water from 15oC to 30oC. The specific
heat of water is 4.18 J/gºC.
SHC: DO ON YOUR OWN

Calculate the specific heat capacity of
copper given that 204.75 J of energy
raises the temperature of 15g of copper
from 25o to 60o.
SHC

216 J of energy is required to raise
the temperature of aluminum from
15o to 35oC. Calculate the mass of
aluminum. (Specific Heat Capacity
of aluminum is 0.90 J/goC).
SHC: Guided

The temperature of a piece of Metal
X with a mass of 95.4g increases
from 25.0°C to 48.0°C as the metal
absorbs 849 J of heat. What is the
specific heat of Metal X?
SHC: Guided

When 435 J of heat is added to
3.4 g of olive oil at 21°C, the
temperature increases to 85°C.
What is the specific heat of the
olive oil?
SHC

A piece of stainless steel with a
mass of 1.55 g absorbs 141 J of
heat when its temperature increases
by 178°C. What is the specific heat
of the stainless steel?
8. Bell Ringer: Tuesday, 09.09.2014
THURSDAY IS BLING DAY!
How much energy would be needed to
heat 300g of copper metal from a
temperature of 10.0ºC to a temperature
of 50.0ºC? (The specific heat of copper
at is 0.385 J/g ºC.)
SHC

Approximate values in J / kg °K of the Specific Heat Capacities of some
substances are:
Air
Aluminum
Asbestos
Brass
Brick
Concrete
Cork
Glass
Gold
Ice
Iron
1000
900
840
400
750
3300
2000
600
130
2100
500
Lead
125
Mercury
14
Nylon
1700
Paraffin
2100
Platinum
135
Polythene
2200
Polystyrene 1300
Rubber
1600
Silver
235
Steel
450
Water
4200
SHC: Specific Heat of Some Common
Materials
Substance
Specific Heat
[(J/gºC)]
Water
Wood
Carbon
Glass
Iron
4.184
1.760
.710
0.664
0.450
So, if the specific heat capacity of a substance is high, it requires a very large
amount of energy to increase the temperature, and if it has a low specific heat
capacity, the required energy will be lower.
SHC

Why does land heat up more quickly than sea
water and how does this help to explain land
and sea breezes?
Specific heat capacities:
 Water
4200 J/kgoC
 Copper
400 J/kgoC
 Aluminium
900 J/kgoC
 Concrete
3300 J/kgoC
 Lead
126 J/kgoC
SHC

Why do you think that houses built of stone
take a long time to warm up but once they are
warm they stay warm for a long time?
Specific heat capacities:
 Water
4200 J/kgoC
 Copper
400 J/kgoC
 Aluminium
900 J/kgoC
 Concrete
3300 J/kgoC
 Lead
126 J/kgoC
SHC

Should saucepans be made of material with
a high or low specific heat capacity?
Specific heat capacities:
 Water
4200 J/kgoC
 Copper
400 J/kgoC
 Aluminium
900 J/kgoC
 Concrete
3300 J/kgoC
 Lead
126 J/kgoC
SHC
Why is water such a good coolant?
Specific heat capacities:
 Water
4200 J/kgoC
 Copper
400 J/kgoC
 Aluminium
900 J/kgoC
 Concrete
3300 J/kgoC
 Lead
126 J/kgoC
Heat: Review for GRADE! pg.158






1. Distinguish between temperature and heat.
2. How does heat flow?
3. How does the specific heat capacity of water compare to other
common substances?
4. How much heat is required to raise the temperature of
140.0 g of mercury by 58°C? (specific heat for mercury is
0.140 J/g°C)
5. Calculate the amount of heat needed to increase the
temperature of 300g of water from 20oC to 50oC. The specific
heat of water is 4.18 J/gºC.
BONUS: A piece of stainless steel with a mass of 3.02g
absorbs 203 J of heat when its temperature increases by
168°C. What is the specific heat of the stainless steel?
Phases of Matter

Matter has two
characteristics:
 Matter
has mass
 Matter takes up
space

All matter is
made up of
atoms
Phases of Matter: Law of Conservation
of Mass

The law of conservation of mass:
States of Matter
Changes between states are called
“phase changes”.
 Caused by a change of heat or
pressure. More often heat.
 HEAT and TEMPERATURE are not
the same thing.

Temperature
Measures the average kinetic energy of
the particles in a substance.
 Is measured in Celsius or Kelvin.
 Kinetic energy is directly related to the
speed of the molecules.
 The faster the particles/molecules are
moving the higher the temperature.

Heat
Heat is a measurement of energy (Joules).
 HEAT and TEMPERATURE are not the same
thing.
 Ex. A cold Lake Superior has more heat
energy than a boiling pot of water.
 For our class, higher temperature means
more heat.

There are no shortcuts to any place worth going. – Beverly Sills
9. Bell Ringer: 09.10.14

Distinguish between HEAT and
TEMPERATURE.
TOMORROW is BLING DAY 
States of Matter
Solid
 Liquid
 Gas
 Plasma

States of Matter: Solid

Particles in a solid:
 Are
tightly packed,
usually in a regular
crystal lattice
pattern.
 vibrate (jiggle) but
generally do not
move from place to
place.
 More dense
States of Matter: Liquid

Particles in a
liquid:
 Are
close
together with no
regular
arrangement.
 Vibrate, move
about, and slide
past each other.
States of Matter: Gas

Particles in a
gas:
 Are
well
separated with
no regular
arrangement.
 Vibrate and
move freely at
high speeds.
Plasma


A plasma is an
ionized gas, in which
a certain proportion
of electrons are free
rather than being
bound to an atom or
molecule.
Plasmas are by far
the most common
phase of matter in
the universe
Characteristics of Gases, Liquids and Solids
gas
liquid
solid
assumes the shape and
assumes the shape of the part retains a fixed volume and
volume of its container
of the container which it
shape
particles can move past one
occupies
rigid - particles locked into
another
particles can move/slide past
place
one another
compressible
lots of free space between
particles
not easily compressible
little free space between
particles
not easily compressible
little free space between
particles
flows easily
flows easily
does not flow easily
particles can move past one particles can move/slide past
rigid - particles cannot
another
one another
move/slide past one another
Phase Change
When a substance changes states it
requires the input or the removal of
energy or change in pressure.
 During a phase change the temperature
does not change, but the amount of
energy does.

Intermolecular Forces
Interactions between particles that cause
them to “stick” together.
 Strongest in solids
 Weakest in gases.
 Strongest when particles move slowly.
 During a phase change IMF are either
weakened or strengthened.

Phase Changes:




Melting – the change
from solid to liquid
Freezing – the change
from liquid to solid
Vaporization – the
change from liquid to
gas
Evaporation –
vaporization from the
surface of a liquid
Phase Changes




Boiling – vaporization
from within as well as
from the surface of a
liquid
Condensation – the
change from gas to
liquid
Sublimation – the
change from solid to gas
Deposition – the change
from gas to solid
Sublimation
Transformation of a substance
to a gas from a solid state with
no liquid transition.
 Ex: Dry Ice does this.

Deposition
When a gas transforms into a
solid without transitioning
through a liquid state.
 Ex. Frost forming on windows.

Where does all the energy go?
During a phase change energy is
added, but the temperature does
not increase.
 The energy goes toward breaking
up weak intermolecular forces
between the particles.

Phase Change Diagram
Directions: Label the phase change of each arc. Brainstorm at least one example for each phase change and write it under
each phase change. In the boxes under the phases draw a small picture of how the molecules are arranged.
Phase Change
Phase Change
pg 502
 1- 6
 ON YOUR OWN PAPER, DO
NOT WRITE QUESTION

You learn something everyday if you pay attention – Ray LeBlond
10. Bell Ringer: 09.11.14

On which points on the graph is water increasing in
temperature?
Phase Change Diagram
Phase Diagram
Phase Change Diagrams
Relates
temperature and
pressure or
temperature and
composition
 phase boundaries
refer to the lines
that identify
where phase
transitions occur.

Phase Change Diagrams

Triple point – the point
on a phase diagram
at which the three
states of matter: gas,
liquid, and solid
coexist
Phase Change Diagrams

Critical point – the
point on a phase
diagram at which the
substance is
indistinguishable
between liquid and
gaseous states
Phase Change Diagrams
Phase Changes
From..
To…
Is
called…
And
energy
is…
Solid
Liquid
Melting
Absorbed
Liquid
Solid
Freezing
Released
Liquid
Vapor
Boiling or Absorbed
Vaporizati
on
Vapor
Liquid
Condensat Released
ion
Solid
Vapor
Sublimatio Absorbed
n
Vapor
Solid
Deposition Released
Phase Change Diagram



A
B
What is the melting point
of this substance?
If the temperature is
increased at point A to
400 º C, what would the
phase of matter be?
If the pressure of the
matter at point B is
increased to 70 atm,
what would be the
phase of matter?
What is work?
In science, the word work has a
different meaning than you may be
familiar with.
 The scientific definition of work is:
using a force to move an object a
distance (when both the force and the
motion of the object are in the same
direction.)

Work or Not Work?
A teacher lecturing to the class
 A mouse pushing a piece of cheese
with its nose across the floor.

Work or Not Work?
Work or Not Work?
A scientist delivers a speech to an audience
of his peers.
 A body builder lifts 350 pounds above his
head.
 A mother carries her baby from room to
room.
 A baseball player hits a baseball to outer
field.
 A mother carries her child up the stairs of the
Eiffel Tower.

Work or Not Work?





A scientist delivers a speech to an audience of
his peers. No
A body builder lifts 350 pounds above his
head. Yes
A mother carries her baby from room to room.
No
A baseball player hits a baseball to outer field.
Yes
A mother carries her child up the stairs of the
Eiffel Tower. Yes
Work
Work - is the transfer of
energy that occurs when a
forces makes an object
move.

Work
Work = Force x Distance
The unit of force is newtons
 The unit of distance is meters
 The unit of work is newton-meters
 One newton-meter is equal to one joule
 So, the unit of work is a joule

W=(F)(D)
Work = Force x
Distance
Calculate: If a man
pushes a concrete
block 10 meters
with a force of 20
N, how much work
has he done?
W=(F)(D)
Work = Force x
Distance
Calculate: If a man
pushes a concrete
block 10 meters with
a force of 20 N, how
much work has he
done? 200 joules
(W = 20N x 10m)
Power

Power is the rate at
which work is
done.
Power =Work*/Time
*(force x distance)


The unit of power
is the watt.
CHECKPOINT 1
1. Blayne pushes a cart 40m
down the hallway with a force
of 10N, how much work is
being done?
CHECKPOINT 1
2. 10, 000J of work is done
to move a car 25m. How
much force was applied?

Checkpoint 3

3. How far would a paper
airplane go if it had a force of
15N and 12J of work was
done?
11. Bell Ringer: 09.12.14
WEEKLY REVIEW 1 DUE TODAY
A
If the
pressure of
the matter at
point A is
increased to
75 atm,
what would
be the phase
of matter?
What would
be the phase
change(s)?
Simple Machines

There are six simple machines
 Lever
 Wheel
and Axle
 Pulley
 Inclined
 Wedge
 Screw
Plane
Simple Machines

A machine is a device that helps make work
easier to perform by accomplishing one or
more of the following functions:
 transferring a force from one place to
another
 changing the direction of a force
 increasing the magnitude of a force, or
 increasing the distance or speed of a force
Simple Machines: Lever



A lever is a rigid bar
that rotates around a
fixed point called the
fulcrum.
The bar may be either
straight or curved.
In use, a lever has
both an effort (or
applied) force and a
load (resistant force).
Simple Machines:
 Changes
the
direction of the
force
 Multiplies effort
force
 Magnifies speed
and distance
 Ex: seesaw,
crowbar, scissors
st
1
Class Lever
Simple Machine: 1st Class Lever
A first-class
lever always
changes the
direction of
force (I.e. a
downward
effort force on
the lever
results in an
upward
movement of
the resistance
force).
Simple Machines:
 Multiply
effort
force
 Mechanical
advantage is
always greater
than 1.
 Ex: bottle opener,
boat oars, wheel
barrow
nd
2
Class Lever
Simple Machine: 2nd Class Lever
A second-class
lever does not
change the
direction of
force. When
the fulcrum is
located closer
to the load
than to the
effort force,
an increase in
force
(mechanical
advantage)
results.
Simple Machine:
 Magnifies
speed
and distance
 Mechanical
Advantage
always less than
1
 Ex: baseball bat,
golf club, broom,
shovel
rd
3
Class Lever
Simple Machine: 3rd Class Lever
A third-class
lever does not
change the
direction of
force; thirdclass levers
always
produce a
gain in speed
and distance
and a
corresponding
decrease in
force.
Simple Machine: Wheel and Axle



The wheel and axle is a
simple machine
consisting of a large
wheel rigidly secured to
a smaller wheel or shaft,
called an axle.
When either the wheel or
axle turns, the other part
also turns. One full
revolution of either part
causes one full
revolution of the other
part.
EX: doorknob, pencil
sharpener, screwdriver,
steering wheel
Simple Machine: Inclined Plane

An inclined plane
is an even
sloping surface.
The inclined
plane makes it
easier to move a
weight from a
lower to higher
elevation.
Simple Machine: Inclined Plane


The mechanical
advantage of an
inclined plane is equal
to the length of the
slope divided by the
height of the inclined
plane.
While the inclined plane
produces a mechanical
advantage, it does so
by increasing the
distance through which
the force must move.
Simple Machine: Pulley


A pulley consists of
a grooved wheel that
turns freely in a
frame called a block.
A pulley can be
used to simply
change the direction
of a force or to gain
a mechanical
advantage,
depending on how
the pulley is
arranged.
Simple Machine: Pulley

A pulley is said to
be a fixed pulley if
it does not rise or
fall with the load
being moved. A
fixed pulley
changes the
direction of a force;
however, it does
not create a
mechanical
advantage.

A moveable pulley
rises and falls with the
load that is being
moved. A single
moveable pulley
creates a mechanical
advantage; however,
it does not change the
direction of a force.
The mechanical
advantage of a
moveable pulley is
equal to the number
of ropes that support
the moveable pulley.
Simple Machine: Wedge


The wedge is a
modification of the
inclined plane. Wedges
are used as either
separating or holding
devices.
A wedge can either be
composed of one or
two inclined planes. A
double wedge can be
thought of as two
inclined planes joined
together with their
sloping surfaces
outward.
Simple Machine: Screw


The screw is also a
modified version of
the inclined plane.
Screw is an inclined
plane wound around
a central cylinder.
While this may be
somewhat difficult to
visualize, it may help
to think of the threads
of the screw as a
type of circular ramp
(or inclined plane).
12. Bell Ringer: Monday, 09.15. 2014
How much work is done on a
20 N block that is lifted 4
meters off the ground by a
pulley?

THURSDAY is SENIOR CITIZENS DAY time to RAID your Grandparent’s
or Great Grandparent’s closet and bring out the suspenders, bowties,
mumus, and hair rollers in support of the TROJANS!
Work: Review

How much work is done on a 10
N block that is lifted 5 meters
off the ground by a pulley?
Work: Review

Malone lifts her book bag 1.5
meters. If the weight of the bag is
12 N, how much work did she do?
Work: Review

Sayer lifts a 45 N bag of mulch 1.2
meters and carry it a distance of 10
meters to the garden. How much
work was done?
Mechanical Advantage
It is useful to think about a machine in
terms of the input force (the force YOU
apply) and the output force (the force
which applied by the machine)
 Input (you, effort)
 Output (resistance, load)

Mechanical Advantage
MA

MA= Fr(output)
Fe(input)
F=force; e=effort;
r=resistance
**use with newtons

MA


MA= de(distance effort)
dr (distance resistance)
d=distance; e=effort;
r=resistance
**use with distance (meters)
Mechanical Advantage: Guided

Jackson lifts a load 10cm with a
pulley system, 20 cm of string had
to be pulled. What is the mechanical
advantage?
MA: Guided

Kent applied 20N of force to turn an ice
cream freezer crank. The crank’s
resistance was 60 N. What was the
mechanical advantage of the crank?
MA: Guided

A simple machine uses 20 N of input
force to lift a 80 N chair. What is the
mechanical advantage of this simple
machine?
CHECKPOINT 2

What is the mechanical advantage
of a lever that has an input arm of
3 meters and an output arm of 2
meters?
CHECKPOINT 2

A rake is held so that its input arm
is 0.5 and its output arm is 1.0
meters. What is the mechanical
advantage of the rake?
MA

Suppose Royce needs to remove a nail from a
board by using a claw hammer. If the effort
length for a claw hammer is 11.0 cm and the
resistance length is 2.0 cm. What is the
mechanical advantage?
MA

A pulley is used to raise a heavy crate. The
pulley is such that an input force of 223 N is
needed to provide an output force of 1784 N.
What is the mechanical advantage of this
pulley?
CHECKPOINT 3
What is the item? What class of
lever is the item?
CHECKPOINT 3
What is the item? What class of
lever is the item?
CHECKPOINT 3
What is the item? What class of
lever is the item?
CHECKPOINT 4
Simple Machines

What are the
purposes of simple
machines?
Simple Machines

Identify some simple
machines in your daily
life (not examples
used today).
W
F
Fr
D
MA
de
MA
dr
Fe
13. Bell Ringer: 09.16.14

YOU HAVE A NEW
SEAT CHECK THE
DESKS!!!
Kent applied 30N of force to turn an ice
cream freezer crank. The crank’s resistance
was 80 N. What was the mechanical
advantage of the crank?
THURSDAY is SENIOR CITIZENS DAY time to RAID your Grandparent’s or Great
Grandparent’s closet and bring out the suspenders, bowties, mumus, and hair rollers
in support of the TROJANS!
Waves


A. Wave is a
repeating
disturbance or
movement that
transfers energy
through matter or
space.
1. A wave will travel
only as long as it
has energy to carry.
Waves

Mechanical
Waves-require a
medium in order
to transport their
energy from one
location to
another.

Electromagnetic
waves-are
transverse waves
that travel
without a
medium. So they
travel through
empty space.
Waves

A wave is a
form of energy
transfer from
one point of
space (medium)
to the other.
Properties of Waves

G. Electromagnetic
waves are transverse
waves that travel
without a medium.
So they travel
through empty space.
1. Electromagnetic
waves travel as
vibrations in
electrical and
magnetic fields.
Waves

2.Electromagnetic
spectrum - name
for the range of
waves when
placed in order
of increasing
frequency.
Waves


1. The two types of
mechanical waves are
transverse waves and
compressional waves.
2. Transverse wave matter in the medium
moves back and forth
at right angles to the
direction that the
wave travels.
Waves

3. In a compression wave, matter
in the medium moves back and
forth along the same direction that
the wave travels.
 4. Compressional waves are also
called longitudinal waves.
Waves

5. Sound
waves
are
compressional
waves.
Compressions
travel through
the air to make a
wave.
Waves

D. Seismic waves
are a combination
of compressional
and transverse
waves. They can
travel through Earth
and along Earth’s
surface.
Waves

A. The transverse wave
has alternating high
points, called crests, and
low points, called
troughs.
1. A compressional wave
has no crests and
troughs, but more dense
regions called
compressions.
3. The less-dense regions
of a compressional wave
is called a rarefactions.
Properties of Waves


B. Wavelength - is the
distance between one
point on a wave and the
nearest point just like it.
1. In a transverse wave,
the wavelength is
distance from crest to
crest or trough to trough.
2. A wavelength in a
compressional wave is
the distance between two
neighboring
compressions or two
neighboring rarefactions.
Properties of Waves


frequency – the
number of full
vibrations each point
of the wave
completes in 1 s
period – time it takes
the wave to travel
one wavelength;
Properties of Waves

The speed of a wave
depends on the
medium it is traveling
through.
1. Sounds waves
usually travel faster in
liquids and solids than
they do in gases.
2. Sound waves
usually travel faster in
a material if the
temperature of the
material is increased.
Properties of Waves



Wave speed – the rate
at which the wave
travels through a given
medium;
v = fλ, where v is
wave speed; f –
frequency; and λ –
wavelength;
Ø here wave speed is
measured in m/s,
frequency - in Hz, and
wavelength – in
meters;
Properties of Waves


F. Amplitude -is related
to the energy carried by
a wave.
1. The greater the wave’s
amplitude is, the more
energy the wave carries.
2. For a compressional
wave with high
amplitude, coils will be
closer together in
compressions and farther
apart during rarefactions.
Properties of Waves

3. For a compressional wave
with low amplitude, coils
will be farther apart in
compressions and closer
together during rarefactions.
4. With transverse waves, a
tall ocean wave has a
greater amplitude than a
short ocean wave.
5. The amplitude of a
transverse wave is the
distance from the crest or
trough of the wave to the
rest position of the medium.
Properties of Waves
Behavior of Waves

A. Reflection occurs
when a wave strikes
an object bounces off
of it. This can occur
with sound, water,
and light waves.
1. According to the
law of reflection, the
angle of incidence is
equal to the angle of
reflection.
Behavior of Waves

B. Refraction- is the
bending of a wave
caused by a change
in its speed as it
moves from one
medium to another.
The greater the
change in speed is,
the more the wave
bends.
Behavior of Waves


C. Diffraction occurs
when an object causes
a wave to change
direction and bend
around it.
1. When an obstacle is
smaller than the
wavelength, the waves
bend around it. If the
obstacle is larger than
the wavelength, the
waves do not diffract
as much.
Behavior of Waves

2. Diffraction affects
radio’s reception. AM
radio waves have
longer wavelengths
than FM radio waves
do. AM radio waves
are capable of
diffracting around
bigger obstacles,
short FM waves do
not diffract as much.
Behavior of Waves

D. Interference - the process where two or more waves
overlap and combine to form a new wave. 1. In
constructive interference, the waves add together.
a. This happens when the crests of two or more
transverse waves arrive at the same place at the same
time and overlap. The amplitude of the new wave will
equal the sum of the amplitudes of the original waves.
2. Destructive interference, the waves subtract from
each other as they overlap.
a. This happens when the crests of one transverse wave
meets the troughs of transverse wave. The amplitude of
the new wave is the difference between the amplitudes
of the waves that overlapped.
Behavior of Waves
Behavior of Waves

E. Resonance - the
process by which an
object is made to
vibrate by
absorbing energy at
its natural
frequencies.
15. Bell Ringer: Friday, 09.19.2014
Sound travels in a ____ wave.
 a. mechanical
c. surface
 b. electromagnetic
d. inverted
Bell Ringer: Monday, 02.24.14

A 10.0 kg block of copper is heated in the Sun
from 25.0ºC to 30.0ºC. Use the table to help
calculate the change in the block's thermal
energy?
Wave Speed
v = fλ, where v is wave speed; f
– frequency; and λ –
wavelength;
 Ø here wave speed is measured
in m/s, frequency - in Hz, and
wavelength – in meters;

Wave Speed
Wave has a frequency of 4 Hz and a
wavelength of 1.6 meters. What is
the speed of the wave?
Wave Speed

Wave has a frequency of 8 Hz and a
wavelength of 2.4 meters. What is the speed
of the wave?
Wave Speed

The speed of sound in air is 280
m/s. If the frequency of Middle D is
264 Hz, what is its wavelength?
Wave Speed

The wake of a boat has a speed
of 5 m/s and a wavelength of
2.3m. What is the frequency?
Bell Ringer: Wednesday, 02.26.14
What is another word
for compressional
wave?

17. Bell Ringer: Monday, 09.22.14

What is the wavelength of a
wave with a frequency of 652
Hz traveling at 26 m/s?
THURSDAY IS HAWAIIAN DAY!!!
Review

The wake of a boat has a speed
of 4 m/s and a wavelength of
2.2m. What is the frequency?
Review

Wave has a frequency of 9 Hz
and a wavelength of 3.2 meters.
What is the speed of the wave?
Nuclear Energy

CHAPTER 9.2
Nuclear Energy

Power plants use heat to produce
electricity. Nuclear energy produces
electricity from heat through a process
called fission. Nuclear power plants use
the heat produced by fission of certain
atoms.
Nuclear Energy


Fission of U-235 splits nucleus in two pieces


Uranium-235
releases neutrons for chain reaction
Nuclear fission chain reaction  releases energy in
the form of heat
Nuclear Energy


-
Nuclear Reactor  device built to sustain a controlled
nuclear fission chain reaction
Main Components of Nuclear Reactor:
reactor vessel
tubes of uranium
control rods
- containment structure
Nuclear Energy




Fission occurs in the reactor vessel. Heat is produced.
The heat is used to heat water to create steam.
The steam is used to turn the turbine in the generator to
produce electricity.
The steam is cooled in the condenser to return to the liquid
phase.
Nuclear Energy

Advantages
 Low cost predictable
power at a stable
price of production
 Do not emit harmful
gases

Disadvantages
 Radioactive waste
due to nuclear
reactors which leaks
radiation contents
 Uranium –
 Non-renewable
resource
Nuclear Energy



A TLD measures ionizing
radiation
Measures amount of
visible light emitted from
a crystal in the detector
when the crystal is
heated.
The amount of light
emitted is dependent
upon the radiation
exposure.
Nuclear Energy
Nuclear Energy
Nuclear Energy
Nuclear Energy
Nuclear Energy
Nuclear Energy
Nuclear Energy
Nuclear Energy
Extra Practice
Pg 835 Chp 4 - 38, 39, 40,
50
Pg 835 Chp 5 – 51, 52
Pg 836 Chp 6 – 64, 65, 66, 67

18. Bell Ringer: Tuesday, 09. 23. 14

Identify the chain reaction…
QUIZ TODAY:
over work and
simple
machines,
waves, nuclear
energy
THURSDAY IS HAWAIIAN DAY!!!
19. Bell Ringer: 09.24.14

What is the wavelength of a wave
with a frequency of 652 Hz traveling
at 26 m/s?
**Reminder – BELL RINGERS are DUE TODAY!!**
TOMORROW IS HAWAIIAN DAY!!!
TEST: UNIT 2
1 person per table
 Cell phones OFF and on front file cabinet
 Need: pencil, scratch paper, calculator
 Provided: Scantron, Test
 AFTER TEST: WORK ON Constructed
RESPONSE CHOOSE 4 (need own paper)
 Can have cell phones after finished with
Constructed Response
