Date: 11/16/2007 Friday 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!!! What is Energy? • The ability to do work • Measured in Units of Joules What are the 1. Chemical: 5 main forms the energy found in the bonds of Energy? that hold atoms together • When bonds are broken, energy is released • Example: fossil fuels (oil, gas, coal), food, a battery 2. Heat: • Associated with the internal motion of atoms • Causes change in temp. & phase changes • Usually results from Friction 3. Electromagnetic: Energy associated with moving charges called electrons Examples: electricity, light, x-rays… 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 Date: 11/19/2007 Monday Aim: How does Potential Energy compare to Kinetic Energy? 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 • Stored energy or energy of Potential position Energy? • Example: Stretched rubber band, or compressed spring What What happens happensto to • Gravitational Potential Energy GPE GPEas as What weight G.P.E. = Weight X Height heightis weight? increases? increases? What is • Energy of Motion Kinetic • K.E. = mass x velocity2 Energy? 2 What happens What happens is toWhat K.E as to K.E as velocity? mass velocity increases? increases? Which Rubber Band has Greater Potential Energy? Which picture demonstrates Potential Energy & what picture shows Kinetic Energy? P. E. K.E. Why doesn’t the still ball have Energy at the bottom of the hill? Date: 11/20/2007 Tuesday Aim: Lab – What is the difference between potential & kinetic energy? Do Now: Handout (Ball: K.E. vs. P.E.) Homework: Complete Lab questions. 1. Where is Potential Energy the greatest? 2. Where is Kinetic Energy the greatest? 3. Where is the least K.E.? 4. Where does K.E. = P.E.? Date: 11/21/2007 Wednesday 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) What is the • Energy can neither be Law of created or destroyed by Conservation ordinary means of Energy? • It can only change from one form to another (During the change some energy is always converted to heat.) 1. Where is Potential Energy the greatest? 1 5 2 3 4 2. Where is Kinetic Energy the greatest? 3. Where is the least K.E.? 4. Where does K.E. = P.E.? 0.10 N 0.22 N Inclined Plane 35 N 2m 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 J Woutput / Winput X 100 = 50/70 X 100 = 71% Date: 11/26/2007 Monday Aim: What are energy conversions? Do Now: Compare Potential to Kinetic Energy. Homework: Study for tomorrow’s Quiz (Energy) Example: What are • Chemical energy in gasoline is energy conversions? 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-B B-C C-D D-E E-F P.E. decreases as K.E. increases P.E. increases as K.E. decreases P.E. decreases as K.E. increases P.E. increases as K.E. decreases P.E. decreases as K.E. increases Chemical Energy to Light & Heat Energy Mechanical Energy to Mechanical Energy (Sound) Mechanical Energy to Electromagnetic Energy (Light) & Heat Energy Electromagnetic Energy (Light) to Chemical Energy Date: 11/27/2007 Tuesday Aim: What is the difference between nonrenewable & renewable energy resources? Do Now: Prepare for quiz. Homework: pg 512 (1-14) Use complete sentences. 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. Non-Renewable Energy Sources • 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. Problems With Non-Renewable Energy Source • 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 With Non-Renewable Energy Source • Transport of fossil fuels has also been associated with oil spills that directly kill wildlife or damage the wildlife’s environment. 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. Solar Energy • 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 Wind 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. Hydroelectric 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. Geothermal 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. Date: 11/28/2007 Wednesday 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. What is matter? • Anything that has mass & takes up space (volume) 1. Solids: What are 3 phases • Have a definite volume & of matter & their shape properties? • Particles are tightly packed together & vibrate in place (least K.E.) 2. Liquids: • Have a definite volume, but take the shape of its container (particles can slide past each other: attractive forces are weaker) 3. Gases: • Have no definite volume or shape What are 3 phases of matter & their • Particles are very far apart properties? & move the fastest • Attractive forces = weakest 4. Plasma: • No definite shape or volume • Exists in very high temps. (ex) stars & lightning) • Charged particles • Thermal Energy • Caused by the internal motion of What is particles of matter heat? • 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 C. 38º C B. 15º C D. 65º C Which has the most heat energy? Date: 11/29/2007 Thursday 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. • The measure of the motion What is (avg. kinetic energy) of temperature? molecules in a substance When does water have a greater K.E. at 50º C or 70ºC? How does heat 1. When heat is added avg. K.E. increases (molecules move effect the faster & spread apart) & temperature of temp. increases a substance? 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. Phase Change Movie Celcius Freezing pt. of What are water some Boiling important temperatures? pt. of water 0º C Fahrenheit Kelvin 32º F 273 K 100º C 212º F 373 K Body Temperature 37º C Absolute Zero -273º C 98.6º F 310 K 0K How can you Heat gained or lost = find the Mass x ΔT x Specific Heat amount of heat (Δ = change) gained or lost Units = calories by a sample of water? 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 Date: 11/30/2007 Friday 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) Absolute Zero: K.E. = Zero No Molecular Motion Adding Heat sublimation What are the various types of phase changes? melting S vaporization L G freezing condensation deposition Removing Heat sublimation example: Dry Ice (solid) changes to CO2 (gas) Heat Energy Phase Change Movie Clip Yahoo! Video What is a heating curve? A graph that shows how the physical state & temperature of a substance is affected by the addition of heat over time Physical State of the Water 1. 2. 3. 4. 5. 6. 7. 8. 9. Between Points A & B___________________ Solid Solid At Point B_____________________________ Between Points B & C___________________ Solid & Liquid At Point C____________________________ Liquid Between Points C & D__________________ Liquid Liquid At Point D____________________________ Between Points D & E___________________ Liquid & Gas At Point E_____________________________ Gas Between Points E & F___________________ Gas Date: 12/3/2007 Monday 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 Type of phases 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 change Heat removed Heat added Heat added Heat added Heat added Heat removed Heat removed Energy Changes 1. Every Diagonal Temperature changes as heat energy is added or removed 2. Every Plateau (Phase Change) Temperature stays the same as heat energy is added or removed • Substances that don’t What are insulators of conduct heat easily heat? • Examples: Glass, Wood, plastic, rubber What are • Substances through which conductors of heat transfers easily heat? • Examples: Copper, Silver, Iron, Aluminum What are 3 methods of heat transfer? 1) Conduction 2) Convection 3) Radiation What are 3 1) Conduction: methods of • Heat transfer occurs by heat transfer? collision of particles (direct contact) • From warmer particles to cooler particles What are 3 2) Convection: methods of • Heat transfer through heat transfer? Liquids & Gases through convection currents • Ex. creates winds & occurs in the mantle of the earth (Its less dense) Cool air sinks (Its more dense) Convection Current molecules move faster & spread apart becoming less dense anything less dense rises 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 Date: 12/4/2007 Tuesday 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: 12/5/2007 Wednesday 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) Name___________ Quiz 1. 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) Date: 12/6/2007 Thursday 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: 12/7/2007 Friday 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!!! Name___________ Quiz 1. ___________ 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. Answer questions 10-12 with the letter(s) in the diagram to the left. 10. Where is P.E. the greatest? 11. Where is K.E. the greatest? 12. Where does K.E. = P.E.?