aim: what are 5 main forms of energy? do now: 1. what is work? 2. what are units of work? homework:...
TRANSCRIPT
Aim: What are 5 main forms of Energy?
Do Now: 1. What is work?
2. What are units of work?
Homework: Have a great weekend!!!
Date: 11/16/2007 Friday
What is Energy? • The ability to do work
• Measured in Units of Joules
the energy found in the bonds that hold atoms together
• When bonds are broken, energy is released
• Example: fossil fuels (oil, gas, coal), food, a battery
1. Chemical:What are the
5 main forms of Energy?
2. Heat:
• Associated with the internal motion of atoms
• Causes change in temp. & phase changes
• Usually results from Friction
Energy associated with moving charges called electrons
Examples: electricity, light, x-rays…
3. Electromagnetic:
4. Mechanical:
energy associated with motion
Examples: Sound, moving water, wind…
5. Nuclear:
• energy associated with the
nucleus of an atom
Ex) Radioactive Substances have unstable nuclei that breakdown
• When the nucleus splits (fission) heat & light are released
• When hydrogen nuclei collide & fuse to form helium fusion occurs (Sun)
• The most concentrated form of energy
Aim: How does Potential Energy compare to Kinetic Energy?
Date: 11/19/2007 Monday
Do Now: 1. Take out homework.
2. Handout
Homework: Read pgs 128-133 & Define the 9 Vocabulary Words on the top of pg 148
(Using Vocabulary)
What is Potential Energy?
• Stored energy or energy of position
• Example: Stretched rubber band, or compressed spring
• Gravitational Potential Energy
G.P.E. = Weight X HeightWhat is
weight?
What happens to GPE as
weight increases
?
What happens to GPE as
height increases?
What is Kinetic Energy?
• Energy of Motion
• K.E. = mass x velocity2
2
What happens to K.E as mass increases?
What happens to
K.E as velocity
increases?
What is velocity?
Which Rubber Band has Greater Potential Energy?
Which picturedemonstratesPotential Energy& what picture shows KineticEnergy?
P. E.
K.E.
Why doesn’t the still ball have Energy at the bottom of the
hill?
Aim: Lab – What is the difference between potential & kinetic energy?
Do Now: Handout (Ball: K.E. vs. P.E.)
Homework: Complete Lab questions.
Date: 11/20/2007 Tuesday
1. Where is Potential Energy the greatest?
2. Where is Kinetic Energy the greatest?
3. Where is the leastK.E.?
4. Where does K.E. = P.E.?
Aim: 1. What is the Law of Conservation of Energy?
2. How did you do on your Work & Machines Exam?
Do Now: Take out homework (lab)
Homework: Have a Happy & Safe Thanksgiving!!! Study for quiz on Energy (Next Tuesday)
Date: 11/21/2007 Wednesday
What is the Law of Conservation of Energy?
• Energy can neither be created or destroyed by ordinary means
• It can only change from one form to another(During the change some energy is always converted to heat.)
12 3 4
51
1. Where is Potential Energy the greatest?
2. Where is Kinetic Energy the greatest?
3. Where is the leastK.E.?
4. Where does K.E. = P.E.?
12 3 4
5
0.10 N0.22 N
Inclined Plane35 N2m
50 N
DE/DR = 2m/1m = 2
FE X DE = 35 N X 2 m = 70 J
FR X DR = 50 N X 1 m = 50 JWoutput / Winput X 100 = 50/70 X 100 = 71%
Aim: What are energy conversions?
Do Now: Compare Potential to Kinetic Energy.
Homework: Study for tomorrow’s Quiz (Energy)
Date: 11/26/2007 Monday
What are energy conversions?
Example:
• Chemical energy in gasoline is transformed into mechanical energy in an automobile engine.
• Energy, in the form of heat, is almost always one of the products of energy transformations.
P.E. is converted into K.E. &K.E. is converted into P.E.
A
B
A-BB-CC-DD-EE-F
P.E. decreases as K.E. increases
P.E. decreases as K.E. increases
P.E. decreases as K.E. increases
P.E. increases as K.E. decreases
P.E. increases as K.E. decreases
Chemical Energyto Light & HeatEnergy
Mechanical Energyto MechanicalEnergy (Sound)
ElectromagneticEnergy (Light)to ChemicalEnergy
MechanicalEnergy toElectromagneticEnergy (Light) &Heat Energy
Aim: What is the difference between non- renewable & renewable energy resources?
Do Now: Prepare for quiz.
Homework: pg 512 (1-14) Use complete sentences.
Date: 11/27/2007 Tuesday
Energy Quiz(Choose: Chemical, Heat, Electromagnetic, Mechanical,
or Nuclear for your answers)
1. Sound is a type of _________ energy.
2. When atomic bonds are broken, _______ energy is released.
3. Energy associated with motion is called ______ energy.
4. The internal motion of atoms is called _______ energy.
5. Light & electricity are forms of _________ energy.
• Fossil fuels: coal, oil, petroleum, and natural gas
• Considered non-renewable because humans use them faster than they can be made
(they take millions of years to make)
• These are a major source of energy in the U.S.
Non-Renewable Energy Sources
• When fossil fuels burns, they release carbon dioxide gas.
• Increases in CO2 creates the “Greenhouse Effect” which is associated with Global Warming.
• Global Warming melts polar ice caps & raises water levels leading to flooding & strange weather patterns.
• The burning of coal also contributes to making sulfuric & nitric acids which make acid rain.
Problems WithNon-Renewable Energy Source
• Transport of fossil fuels has also been associated with oil spills that directly kill wildlife or damage the wildlife’s environment.
Problems WithNon-Renewable Energy Source
• Examples: Sunlight (a major source of energy for the earth), wind, falling water, tides, geothermal, & biomass
• Each of these create very little or no pollution
• Wood (biomass) can be considered a renewable energy resource as long as trees are replanted.
Renewable Energy Source
• Photovoltaic cells convert solar energy directly into electrical energy. Ex) solar calculator
• The heat from the Sun can also be used to boil water to create steam to turn a turbine & make electricity
Solar Energy
• As the Sun strikes Earth, the atmosphere is unevenly heated creating wind.
• Wind energy can be used to turn the turbines of a generator producing electricity.
Wind Energy
• Moving water can turn a turbine to create electricity.
• Water can be heated by burning biomass (wood, manure…), geothermal energy, or the sun to create steam.
• Steam can also turn a turbine to create electricity.
Hydroelectric Energy
• In the middle of the earth is hot liquid rock called magma.
• The heat from inside Earth, can be used to heat homes or boil water to create steam that drives turbines.
Geothermal Energy
Aim: How is matter affected by heat?Do Now: 1. Take out homework.
2. What is matter?
3. What is heat?
Homework: Read pgs 260-265 Answer Self-check Questions (1-3) on pg 265.
Date: 11/28/2007 Wednesday
What is matter?
• Anything that has mass & takes up space
(volume)
What are 3 phases of matter & their properties?
• Have a definite volume & shape
• Particles are tightly packed together & vibrate in place (least K.E.)
• Have a definite volume, but take the shape of its container
(particles can slide past each other: attractive forces are weaker)
1. Solids:
2. Liquids:
What are 3 phases of matter & their properties?
• Have no definite volume or shape
• Particles are very far apart
& move the fastest• Attractive forces = weakest
3. Gases:
• No definite shape or volume• Exists in very high temps. (ex)
stars & lightning)• Charged particles
4. Plasma:
What is
heat?
• Thermal Energy
• Caused by the internal motion of particles of matter
• Always flows from areas of
Hot (warm) to Cold (cool)
Until both areas reach the same temp.
• Addition or removal causes phase changes to occur (physical changes of matter from one state to another)
Where will the heat flow?
A. 20º C B. 15º C
C. 38º C D. 65º C
Which has the most heat energy?
Aim: How does heat affect temperature?
Do Now: 1. Take out homework.
2. Are phase changes physical or chemical changes? Why?
Homework: Read pgs 254-259 & Answer self-check questions (1-5) on pg 259.
Date: 11/29/2007 Thursday
What is temperature?
• The measure of the motion (avg. kinetic energy) of molecules in a substance
When does water have a greater K.E.at 50º C or 70ºC?
How does heat effect the temperature of a substance?
1. When heat is added avg. K.E. increases (molecules move faster & spread apart) & temp. increases
2. When heat is removed avg. K.E. decreases (molecules move slower & usu. closer together) & temp. decreases
• Most substances expand when heated & contract when cooled.
• Water is an exception, expanding when changing to ice.
• Temperature also affects the solubility of some substances in water.
What are some important temperatures?
Celcius Fahrenheit KelvinFreezing
pt. of water
Boiling pt. of water
Body Temperature
0º C
100º C
37º C
32º F
212º F
98.6º F
273 K
373 K
AbsoluteZero -273º C 0 K
310 K
How can you find the amount of heat gained or lost by a sample of water?
Heat gained or lost =
Mass x ΔT x Specific Heat
(Δ = change)
Units = calories
Specific Heat =
The ability of a substance to absorb heat
1) The temperature of a 10 gram sample of water increases from 20º C to 40º C. How much heat energy did it gain?
Heat gained = Mass x ΔT x Specific Heat
Heat gained = 10 g x 20º C x 1 cal/g. º C
Heat gained = 200 calories
2) The temperature of a 5 gram sample of water decreases from 50º C to 45º C. How much heat did it lose?
Heat gained = Mass x ΔT x Specific Heat
Heat gained = 5 g x 5º C x 1 cal/g. º C
Heat gained = 25 calories
Aim: What are various types of phase changes?
Do Now: 1. Take out note-packet & homework.
2. What is absolute zero?
Homework: Study for next Thursday’s Exam on Energy & Heat.
Handout (phase changes)
Date: 11/30/2007 Friday
Absolute Zero:K.E. = ZeroNo Molecular Motion
What arethe varioustypes of phase changes?
S L G
Adding Heat
Removing Heat
sublimation
deposition
melting
freezing condensation
vaporization
sublimation example: Dry Ice (solid) changes to CO2 (gas)
Heat Energy
Phase Change Movie Clip - Yahoo! Video
What is a heatingcurve?
A graph that shows how the physical state & temperature of a substanceis affected by the additionof heat over time
Physical State of the Water
1. Between Points A & B___________________
2. At Point B_____________________________
3. Between Points B & C___________________
4. At Point C____________________________
5. Between Points C & D__________________
6. At Point D____________________________
7. Between Points D & E___________________
8. At Point E_____________________________
9. Between Points E & F___________________
Solid
Liquid
Gas
Solid & Liquid
Liquid & Gas
Solid
Liquid
Liquid
Gas
Aim: 1. What are differences between insulators & conductors of heat? 2. What are 3 methods of heat transfer?
Do Now: 1. Take out handout & note-packet
2. How does an ice cube form?
Homework: Read pgs 266-270 & answer self-check questions (1-5) on pg 270
Date: 12/3/2007 Monday
Type of phases change Heat change
Freezing(liquid to solid)
Melting(solid to liquid)
Vaporization(liquid to gas)
Evaporation(liquid to gas)
Sublimation(solid to gas)
Condensation(gas to liquid)
Deposition(gas to solid)
Heat removed
Heat added
Heat added
Heat added
Heat added
Heat removed
Heat removed
Energy Changes1. Every Diagonal 2. Every Plateau
(Phase Change)
Temperature stays the same as heatenergy is added orremoved
Temperaturechanges as heatenergy is added orremoved
What are insulators of heat?
• Substances that don’t conduct heat easily
• Examples: Glass, Wood, plastic,
rubber
What are conductors of heat?
• Substances through which heat transfers easily
• Examples: Copper, Silver,
Iron, Aluminum
What are 3 methods of heat transfer?
1) Conduction
2) Convection
3) Radiation
What are 3 methods of heat transfer?
1) Conduction:
• Heat transfer occurs by
collision of particles (direct contact)
• From warmer particles to cooler particles
What are 3 methods of heat transfer?
2) Convection:
• Heat transfer through Liquids & Gases through convection currents
• Ex. creates winds & occurs in the mantle of the earth
Cool air sinks(Its more dense)
(Its less dense)
molecules move faster & spread apart becoming
less dense anything less dense rises
Convection Current
molecules move slower & closer
together becoming more dense, anything
more dense sinks
What are 3 methods of heat transfer?
3) Radiation:
• Heat transfer by infrared waves through empty space (a vacuum)
• Ex) The sun radiates heat
Aim: Lab: What are examples of conduction & convection?
Do Now: 1. Take out homework.
2. Brainpop: States of Matter
Homework: Study for Quiz on Heat
Date: 12/4/2007 Tuesday
Aim: 1. Take & Go over Quiz 2. Review: What do you know about
Energy & Heat?Do Now: Prepare for Quiz.
Homework: Bring a Pencil & Study for Exam on Energy & Heat (Part II)
Date: 12/5/2007 Wednesday
Name___________ Quiz1. Heat never flows from areas of ___________ to
___________. (Hot to Cold, or Cold to Hot)2. ___________have particles that are close together
& move the slowest. (Solids, Liquids or Gases)3. ___________Phase changes are (chemical/physical)
changes of matter from one state to another.4. ___________is the transfer of heat energy by
molecular (or direct) contact. (Conduction or Induction)
5. ___________The condensing point of a substance is equal to the __________ point. (Boiling point or Freezing point)
6. ___________ is the measure of the average kinetic energy of a substance. (Heat or Temperature)
7. ___________During condensation (gas to liquid) is energy absorbed or released?
8. ___________A phase change directly from a solid to a gas is known as ____________. (Melting, Condensation, Sublimation, or Deposition)
9. ___________When a substance is heated, its molecules vibrate (move):
A) Slower & closer together
B) Slower & farther apart
C) Faster & farther apart
D) Faster & closer together
10. ___________These pictures demonstrate a process of heat transfer known as________. (Conduction, Convection, or Radiation)
Aim: Exam: What do you know about Energy & Heat? (Part (II)
Do Now: Take out pencil, put up binders & Prepare for Exam.
Homework: Bring a Pencil & Study for Exam on Energy & Heat (Part I)
Date: 12/6/2007Thursday
Aim: Exam: What do you know about Energy & Heat? (Part (I)
Do Now: Take out pencil, put up binders & Prepare for Exam.
Homework: Have a good weekend!!!
Date: 12/7/2007Friday
Name___________ Quiz1. ___________ is the energy trapped within
the bonds that hold atoms together.
2. ___________ is the most concentrated form of energy.
3. ___________ are units used for energy.
4. ___________is energy associated with moving charges (electrons).
5. ___________is the ability to do work.
6. ___________ is the type of energy associated with the internal motion of molecules.
7. ___________is energy of position.8. Potential Energy depends upon the
weight X _________ of an object.9. The Law of ___________ of __________
states that energy can’t be created or destroyed by ordinary means it can only change from one form to another.
10. Where is P.E. the greatest?
11. Where is K.E. the greatest?
12. Where does K.E. = P.E.?
Answer questions 10-12 with the letter(s)in the diagram to the left.