Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Theoretical and experimental justification for the Schrödinger equation wikipedia , lookup
Relativistic mechanics wikipedia , lookup
Gibbs free energy wikipedia , lookup
Thermodynamic temperature wikipedia , lookup
Internal energy wikipedia , lookup
Eigenstate thermalization hypothesis wikipedia , lookup
ENERGY energy ! All changes in a system - physical or chemical - are accompanied by a change in _________________. Energy - What is it? go to school, move, swim, walk to the kitchen, play tennis, try, deal with Emmanisa, “I don’t have enough energy to _________________________________________” get out of bed, think, come to Chemistry/Interp, live, eat do something to __________________________ Energy is associated with ________________________________________________ doing / action = CHANGE Energy - defined as the potential to do work ‘energy’ Greek for ‘work within’ ability to make happen What’s Work ? everything (effort), building a tree house or tire swing, pushing first, examples of work : a carrot, pulling a banana, running in field hockey, cooking a BIG meal, growing, living with siblings, shoveling snow, split why is energy involved ? wood work involves moving something against a force (pushes / pulls) - you do work, or work is done, on an object to move it against a force (the object gains energy) - work is done by an object when it moves with a force (the object loses energy) The Rock…. There are Four Forces - gravity - “Rules the Cosmos”, Hecht attractive force between ALL objects - scales with mass - electromagnetic (e/m) between charged objects - governs chemistry and biology attractive between oppositely charged objects repulsive between like charged objects + + + includes: the forces of Chemistry - friction cohesion adhesion chemical bonds - drag tension - fist and wall collisions - teeth and hamburger (contact forces) - strong - holds parts together in the nucleus protons, neutrons / quarks - weak - transforms one type of quark into another associated with nuclear decay - - forces of nucleus and nuclear decay - effective over very small distances <10-15m Forces and Energy are properties of matter Forces - exist between bodies - cannot have a force with ONE body if one considers energy as Energy - consequence of forces - then energy is a property of matter energy is of a body, not an entity unto itself - you cannot have a cup of energy, anymore than you can have a cup of color Energy is stored (in matter) as position potential energy (PE) – energy a body possesses due to its ______________ - implies another body (as position is defined relative to something else) - if there are two bodies, they interact by one or more forces - PE is the energy stored in the bodies due to the force between them - the magnitude of the force changes as the relative position of the bodies changes, so….. the PE depends on the distance between bodies motion kinetic energy (KE) – energy a body possesses due to its _______________ - larger mass, moving faster = higher KE - can’t have motion without a push/pull OR two or more bodies must interact via a force for one (or all) of them to move The Waterfall The Dam OPEN THE DAM!! The Lake The Turbine The River The Waterfall The Dam HIGH PE water at the top of the lake has high PE as it falls due to gravity its PE turns into KE the moving water can do work on the turbine The Lake The Turbine PE – the potential to do work work involves moving cannot “see” the expression of energy until objects are in motion PE KE for work to be done LOW PE The River Forms of Motion (Kinetic) Energy kinetic -energy a body possesses due to its motion as a whole object the whole body moves in a uniform (one) direction OR uniform motion of all the parts that make up the whole thermal -energy a body possesses due to the motion of its parts the parts = all parts down to the atomic/subatomic scale the motion = random (all directions) motion temperature measure as the ______________ hot / cold water and dye…. Forms of Positional (Potential) Energy - Because there are different types of forces, bodies can interact or move with or against these different forces. Change occurs as a consequence of these different forces, so we see/experience different manifestations of energy. OR There are different forms of potential energy depending on the different force involved. FORCE gravitational chemical nuclear elastic electrical INTERACTING BODIES Forms of Potential Energy There are different forms of energy depending on the different force involved. FORCE INTERACTING BODIES gravitational PE gravity all bodies - scales with mass stored in any body due to its gravitational interaction with another body nuclear PE nuclear particles (protons, neutrons, quarks) strong / weak stored in the nuclear particles e/m any protons (+) and electrons (-) electrical PE stored in an electron due to its position relative to other protons and electrons elastic PE e/m protons (+) and electrons (-) of bonded atoms stored in bonded atoms due to the compression/stretching of chemical bonds chemical PE e/m protons (+) and electrons (-) of bonded atoms stored in a bonded atom due to its e/m interaction with the other bonded atom And Radiation – radiowaves, microwaves, infrared, visible, ultraviolet, X-ray, gamma ray solar energy - primarily infrared (IR), visible, ultraviolet (UV) radiation where is radiation ? in space ( not in matter ) originates in matter – travels through space e/m in origin radiation is produced as charged particles move relative to each other NOTE: the sun is HOT - 3,000,000 C (core) - 6,000 C (surface) . BUT, the thermal energy does not reach the Earth 92.3×106 miles away. We are warmed by the infrared radiation nice example battery – electrical PE hook up the battery – electrical PE to KE (electrons moving) can do the “work” (light the bulb or whatever) the electrons flowing in the wire move past other electrons/protons generates radiation It is practically impossible ( in practice, cannot do ) to calculate the total amount of energy a body possesses because one would need to consider the interaction of that body with __________________ every other body ___________________________________________________________________ in the universe (interacting through one or more of the four forces) However, there is a law about the total amount of energy in the universe: Conservation of Energy The Law of ______________________________________ that states _______________________________________________________ energy cannot be created or destroyed _____________________________________________________________ OR the total amount of energy in the universe is constant energy can be ________________________ transformed transferred energy can be _______________________ even though the total by _____________________ work energy cannot be calculated, ________________________ heat the amount of energy radiation ________________________ gained or lost by an object can be Examples of Transfer and Transformation of energy Lifting a rock with your hand you moved the rock against / with ________________________________________________ gravity (between the Rock and Earth) you did __________ on the rock work transfer of energy by __________ work from _______ to ___________ you the Rock the rock gained / lost ____________________________________ gravitational PE as a result of _________________________________ your arm pushing transformation _________________________________ muscles contracting _________________________________ food consumed next slide energy stored in available to do… (many steps / chemical changes) food ……………………….……………. ADP + phosphate + ENERGY chemical PE energy stored in food as ____________________________ next slide many steps food (mostly carbohydrates) glucose + oxygen ATP + carbon dioxide + water energy stored in ATP (hydrolysis) ADP + phosphate + ENERGY useful energy in food is stored in chemical bonds back to previous slide available to do… Examples of Transfer and Transformation of Energy Transfer of Energy by Heat When you heat something it gets _________________________________ hotter So, heat / heating has something to do with Temperature and Hot and Cold What happens when you put a hot object next to a cold object ? ____________________________________________________________ the cold object gets hotter, and the hot object gets colder ____________________________________________________________ until they are at the same temperature HOT COLD How ? Something that is HOT has relatively high thermal energy the individual particles of the object are moving relatively FAST Something that is COLD has relatively low thermal energy the individual particles of the object are moving relatively SLOWLY relatively high thermal energy particles of the object are moving relatively FAST HOT COLD relatively low thermal energy particles of the object are moving relatively SLOWLY HOT COLD HOT COLD at the interface, the “hot” and “cold” particles collide faster goes slower (colder), slower goes faster (hotter) the interface spreads throughout the bodies, until the particles are moving at the same speed (at the same temperature) HOT COLD HOT COLD at the interface, the “hot” and “cold” particles collide faster goes slower (colder), slower goes faster (hotter) the interface spreads throughout the bodies, until the particles are moving at the same speed (at the same temperature) HOT EDIU COLD HOT MEDIUM COLD HOT MEDIUM COLD Transfer of Energy by Heat energy is transferred (technically) Heat is not ____________________ it is a way that ______________________ a form of energy (Hecht quote) “Heat is thermal energy in transit, and once transferred it is no longer called heat” [it is again thermal energy]. (Thermal) energy is transferred by heat between objects that are _____________________________________ in contact and, _________________________________ at different temperatures Law of Conservation of Energy (and Matter) and our Energy Crisis Law of Conservation of Energy Over hundreds of years, experiments have shown that there is no net gain or loss of energy in the universe (as long as one accepts that matter is a form of energy). So, how can we be in an “energy crisis” ? How can we be running out of energy ? we can’t be we are running out of energy in useful forms (or places) (useful for some purpose) So “consuming energy” means ______________________________________ transforming /transferring from ________________________________________________________________ useful forms to less useful (or not useful for the same purpose) forms fossil fuels (matter) What are we running out of with respect to the energy crisis? ________________ (mostly ~90%) burning it (transformed) What is happening to this ? ________________________ Type of change ? ________________________ chemical (evidence? flame ) What are we running out of with respect to the energy crisis? _________________ petroleum (matter) (mostly ~90%) burning it What is happening to this ? ________________________ Type of change ? __________________________ chemical (evidence? flame ) (burning fossil fuels) Fuel + O2 CO2 + H2O new substances form - bonds break / new bonds form Chemical change: __________________________________________________________ in chemical bonds With respect to a chemical change, useful energy is stored __________________________ (chemical PE) so, as the fuel burns, chemical PE of (Fuel + O2) chemical PE of (CO2 + H2O) BUT, the point of burning the fuel is not to produce CO2 and H2O. thermal energy (and radiation) The point is to “get the energy out” as ___________________________ where was the thermal energy and radiation to begin with ? ____________ in the fuel (and O2) as ? _____________________ chemical PE some of the chemical PE of the fuel (and O2) is transformed to thermal energy and radiation The Waterfall The Dam Gravitational PE HIGH Gravitational PE high water total energy total energy low water GravPE (high water) this amount of gravitational PE is transformed to KE (energy of the moving water) The Turbine LOW Gravitational PE GravPE (low water) + KE (moving water) if the falling water if thehits falling water hits the surface of athe pond/river turbine KE+PE (splash) KE (sound) thermal electricity Chemical PE (bond energy) Burning Fuel The Fire HIGH Chemical PE fuel (C2H6) + O2 total energy this amount of chemical PE is transformed to thermal and radiation total energy CO2 + H2O ChemPE (fuel + O2) LOW Chemical PE ChemPE (CO2 + H2O) + thermal & radiation The Energy “Crisis” So “consuming energy” means _______________________________________ transforming /transferring from ________________________________________________________________ useful forms to less useful (or not useful for the same purpose) forms Transformation (consumption) of energy chemical PE (fuel + O2) chemical PE (CO2 + H2O) + radiation & thermal energy transferred transformed LCE – no gain / loss in energy….. so…… chemical PE (fuel + O2) has to equal chemical PE (CO2 + H2O) + radiation & thermal energy so, what’s the problem ?… no energy has been lost…. 1. low (not as useful) 2. Where does thermal energy go? - out / everywhere - escapes in to the universe – “lost” / not useful To heat our buildings the energy is ultimately “lost” as thermal energy escaping into the universe transfer of thermal energy by heat cold HOT air (some of) chem PE (fuel) thermal energy (flame) transform WARM COLD transfer of thermal energy by heat To produce electricity transfer of kinetic energy by work cold transfer of thermal HOT energy by heat (some of) chem PE (fuel) thermal energy (flame) transform electricity light (radiation) transform + thermal energy kinetic energy electricity transform To produce electricity electricity light (radiation) transform + thermal energy HOT COLD transfer by heat the energy is ultimately “lost” as thermal energy escaping into the universe transfer ansfer kinetic energy electricity transform thermal energy (flame) form Transportation transform thermal kinetic hot gases expand - can only expand “up” moves forward transfer of kinetic energy by work cold HOT transfer of thermal energy by heat (some of) chem PE (fuel) (KE) KE thermal energy transform thermal energy (flame) transform transform the energy is ultimately “lost” as thermal energy escaping into the universe work Useful Energy can do _____________ force move something with respect to a __________ a direction implies _______________ (outward/inward is a direction) to move something (THING 1) move towards Thing1 something else (THING 2) must _________________ ____________________ and HIT Thing1 Useful Energy can do work = move some object in some direction Thermal energy random motion of particles within a mass (object) cannot do __________________ (no net direction of motion) work UNLESS it is trapped in an expandable/contractable container (the hot mass) example: in a piston, trapped hot gases expand to push a piston up in a power plant, trapped hot gases expand thermal kinetic to turn a turbine untrapped, thermal energy escapes into the universe and is no longer useful to do work thermal energy = degraded energy The Waterfall The Dam The Lake The Turbine The River The Waterfall The Dam HIGH PE The Lake The Turbine LOW PE The River