Chapter 5: Energy and energy resources - PowerPoint Presentation

Chapter 5: Energy and energy resources Material on Final Exam 1

Essential Questions What is energy? What are potential and kinetic energy? How is energy related to work? What are different forms of energy?What is the law of conservation of energy?How does friction affect energy transformations?How are different types of energy used?What are nonrenewable energy resources?What are renewable energy resources?Why is it important to conserve energy? 2

Section 1: Forms of energy Energy is known by the changes it causes Energy is the ability to _________________ (do work).Work is the transfer of energy.Work and Energy are closely related: Energy is transferred by a force moving an object through a distance. Energy causes weather! cause change 3 Work and energy are both expressed in SI units known as a ______________ Joule (J)

Section 1: Forms of energy Types of Energy We break energy down into several categories Mechanical energy KineticPotentialThermal energyChemical energy Electrical energy Electromagnetic energy Nuclear energy 4

Section 1: Forms of energy Kinetic energy is energy due to ____________ All moving objects have kinetic energy. depends upon its _______ and ____________FORMULA - SI Unit = Joule KE = mv 2 2 5 motion mass speed

Section 1: Forms of energy Compare the truck to the green car Compare the blue car to the green car 6

Section 1: Forms of energy Math practiceA 70 kg man is walking at a speed of 2 m/s. What is his kinetic energy? You try! A 1400 kg cart moves at 25 m/s. What is the cart’s kinetic energy? 7

Section 1: Forms of energy A 50 kg cheetah has a KE of 18,000J. How fast is the cheetah running? 8

Write the answer on your gold sheet. What would you need to do to maximize kinetic energy? What would you need to do to minimize kinetic energy? ANSWER MUST BE 3 LINES OF TEXT FOR FULL CREDIT! Writing Prompt #1 (of 3) 9

Section 1: Forms of energy Potential Energy is _________ energy due to interactions between objects or particles Often due to ____________ or ____________ Three major types: __________________ is based on the weight and height of an object from the ground____________ is stored in objects that are compressed or stretched____________ is based on energy stored in the chemical bonds between atoms 10 stored position shape Gravitational Elastic Chemical

Section 1: Forms of energy 11

Section 1: Forms of energy FORMULA – PE = mgh or PE = wh REMEMBER – weight = forceTo get weight, do mass (kg) x gravity 12

Section 1: Forms of energy Math practice What is the gravitational potential energy of a cat that weighs 40 N standing on a table that is 0.8 m above the ground? You try! What is the gravitational potential energy of a diver who weighs 500 N standing on a platform that is 10 m off the ground? 13

Section 1: Forms of energy What is the gravitational potential energy of a diver who has a mass of 61 kg standing on a platform that is 8 m off the ground? 14

Write the answer on your gold sheet. Where would you put an object to maximize its GPE? Where would GPE be zero? ANSWER MUST BE 3 LINES OF TEXT FOR FULL CREDIT! Writing Prompt #2 (of 3) 15

Section 9-1—What is Energy 16

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Section 1: Forms of energy Mechanical energy is the ________ energy of an object or a group of objects due to large-scale _________ and ______________________ associated with the __________ and ___________ of objects.Both kinetic energy and potential energy are examples of mechanical energy.Examples: speeding train bouncing balls, sprinting athletes, baseball falling through the air. FORMULA ME= (KE+PE) 18 total motions interactions motion position

Section 1: Forms of energy Math practiceBalls being juggled by a juggler has a potential energy of 20 J and kinetic energy of 600 J. What is the ball’s total mechanical energy? You try! Let’s say a pin being juggled by a juggler has a potential energy of 30 J and the kinetic energy of 500 J. What is the pin’s mechanical energy? 19

Section 1: Forms of energy A roller coaster has the potential energy of 10,000 J and the kinetic energy of 50,000 J. What is the coaster’s mechanical energy? 20

Section 1: Forms of energy Sound energy is the energy that _________ carries Comes from vibrating objects Thermal energy is energy due to the motion of __________ that make up an objectAll matter has thermal energy because all ____________ are in constant random _____________As temperature _________________, the atoms move _____________The ____________ the atoms move, the ____________ thermal energy. 21 sound particles particles motion increases faster faster higher

Section 1: Forms of energy Electrical Energy is the energy that an _____________ ____________ carries Radiant Energy is the energy that _____________________ waves carry Sometimes called __________ energy 22 electric current electromagnetic light

Section 1: Forms of energy Nuclear energy is energy stored in the __________ of an atom Nuclear __________ is a process of releasing energy through ______________ nuclei apart.Nuclear _____________ releases energy when a less massive nuclei ____________ to form a more massive nucleus. 23 nucleus fission breaking fusion combine

Section 2: Energy Transformations Energy transformations are changes of energy from one form to another 24

Section 9-2—Energy Conversions 25

In lighting a match , your muscles use ___________ energy moving your hand to strike the match, friction converts some of the matches _________ energy into _________ energy. The thermal energy triggers a chemical reaction on the match tip, releasing some of the match’s ___________ energy. The stored chemical energy is then converted into _________ energy and ______________________ energy in the flame. 26 Section 2: Energy Transformations nucleus kinetic thermal chemical thermal electromagnetic

Write the answer on your gold sheet. Explain three different energy forms that would be found in the process of burning wood to boil water to make steam. ANSWER MUST BE 3 LINES OF TEXT FOR FULL CREDIT! Writing Prompt #3 (of 3) 27

Section 2: Energy Transformations Energy transformations often occur between kinetic energy and potential energy What do you notice about the total energy ?28

In energy conversions with mechanical energy , some energy is always _______ as heat (Thermal energy) due to _____________ Section 2: Energy Transformations The Law of Conservation of Energy states that energy can be ______________________ from one form into another or _____________________ from region to another, but energy ___________ be ___________ or _______________ 29 transformed transferred cannot created destroyed lost friction

Section 2: Energy Transformations Uses of energy 30 Thermal Energy Cook food, provide warmth, transfers to mechanical energy (engines) Chemical Energy Photosynthesis stores radiant energy as sugar, food, fuel, batteries Radiant Energy Microwaves, light, cell phones, radio, TV Electric Energy Video games, mp3 players, hair dryers Waste Energy Cannot be used

Section 3: Energy Resources Sources of energy All energy is ultimately traced back to the sun Food (photosynthesis), wood, fossil fuelsWe use this energy indirectly via power plants 31

Section 3: Energy Resources Nonrenewable Resources are energy resources that are available in ________ amounts or that is ________________ than it is replaced in nature Fossil fuels are the remains of ancient organisms that can be burned as an energy resource Examples include: ______, ____________, and _________ Nuclear energy comes from the decay of __________ nucleiThe _______ from the radioactive decay is what heats the water in the power plant 32 limited used faster coal natural gas oil Uranium heat

Section 3: Energy Resources Renewable Resources are energy resources that are __________ as fast as, or faster than they are used Hydroelectric Power Plants The potential energy of water in a reservoir can be changed into kinetic energy as the water flows through a dam.Solar Energy Sunlight can be changed into electrical energy through solar cells Also considered an inexhaustible energy resource because it cannot be used up Wind Energy The kinetic energy of wind can turn the blades of a windmill or a wind turbine. 33 replaced

Section 3: Energy Resources Renewable Resources are energy resources that are replaced as fast as, or faster than they are used Wind Energy The kinetic energy of wind can turn the blades of a windmill or a wind turbine. Biomass Burning of material from plants and animals.Geothermal Energy The thermal energy deep within the earth 34

Section 3: Energy Resources Conserving Energy We need to ___________ our use of nonrenewable resources to prevent shortages in the future Example: turning off lights when not in use We can also switch to renewable resources to prevent shortages of nonrenewable resources35 conserve