< BackNext >PreviewMain Section 1 What Is Energy? H.W.-type your homework here Warm-up #40- page 238 Look at the picture on page 238 and read the caption. A. What form of energy does the car use? B. What types of energy have you used today? Teacher notes: pass out the student handout. Students fill in the answers while watching this power point. Chapter 9

< BackNext >PreviewMain Section 1 What Is Energy? S8P2. Students will be familiar with the forms and transformations of energy. a. Explain energy transformation in terms of the Law of Conservation of Energy. b. Explain the relationship between potential and kinetic energy. c. Compare and contrast the different forms of energy (heat, light, electricity, mechanical motion, sound) and their characteristics. GPS

< BackNext >PreviewMain Section 1 What Is Energy? Energy and Work: Working Together 1. Energy is the ability to do work. Work is done when a force causes an object to move in the direction of the force. 2. Work is a transfer of energy. 3. Energy and work are expressed in units of joules (J). Chapter 9

< BackNext >PreviewMain Section 1 What Is Energy? Chapter 9 4.

< BackNext >PreviewMain How to add video clips to Power Point Presentations. 1. Log into streaming.discoveryeducation.com (Ask your Media Specialist for your password if you don’t have it) 2. Type forms of energy into search box, choose DE streaming, video segment, Look for videos created after When you find a segment you like, check the box and then click on the download arrow. Sometimes a video will not download. Try using Firefox as your browser. Name the video what it is about so that you know which slide to insert. Save it in the same folder as the power point. 4. Insert it into power point. Drag the corner to make it as big as you’d like. For more details,

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< BackNext >PreviewMain Section 1 What Is Energy? Kinetic Energy 4. Energy is transferred from the first object to the second object 5. Kinetic energy is the energy of motion. All moving objects have kinetic energy. 6. Kinetic Energy Depends on Mass and Velocity If you know an object’s mass (m) and its velocity (v), you can calculate the object’s kinetic energy with the following equation: Chapter 9 kinetic energy  mv 2 2

< BackNext >PreviewMain Teachers, to insert animation from online textbook, log into the online textbook my.hrw.com. Choose chapter 9, click on the red eactivities tab, choose the animation. There should be the word file at the top of the animation box. Click on file, then save to the same folder as the power point. Go back to your power point presentation and insert object, then find the file, then insert.

< BackNext >PreviewMain Section 1 What Is Energy? 7. & 8. Kinetic Energy Chapter 9 Click below to watch the Visual Concept. Visual Concept 7. The greater the mass, the greater the kinetic energy 8. The more kinetic energy, the greater the damage.

< BackNext >PreviewMain Section 1 What Is Energy? Potential Energy Not all energy has to do with motion. 9. Potential energy is the energy an object has because of its position, shape, or condition. Once the ball or the arrow is released, the stored energy is converted to kinetic energy.

< BackNext >PreviewMain Potential Energy

< BackNext >PreviewMain 10. When you lift an object, energy is transferred to the object, which gives the object gravitational potential energy.

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< BackNext >PreviewMain Section 1 What Is Energy? Mechanical Energy 11. Mechanical energy is the total energy of motion and position of an object. Both kinetic energy and potential energy are kinds of mechanical energy. 12. The equation to find mechanical energy is: mechanical energy  potential energy  kinetic energy ME = PE + KE Chapter 9

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< BackNext >PreviewMain The kinetic energy decreases as the ball rises because it slows down. When the ball reaches the highest point, it stops and has maximum potential energy. As the ball drops, it has the greatest kinetic energy the closer it gets to her hand.

< BackNext >PreviewMain Section 2 Energy Conversions Chapter 9 As the skateboarder on the next slide travels up and down the half-pipe, his energy changes back and forth between kinetic energy and potential energy

< BackNext >PreviewMain Complete the Jumping Frog activity on the laminated sheet. Answer questions when you have completed this activity.

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< BackNext >PreviewMain 20. A 21. C 22. G 23. E 24. B 25. D 26. F

< BackNext >PreviewMain Section 1 What Is Energy? Other Forms of Energy Thermal Energy is all of the kinetic energy due to random motion of the particles that make up an object. All matter is made up of particles that are always in random motion. So, all matter has thermal energy. Thermal energy increases as temperature increases and increases as the number of particles increases. Chapter 9

< BackNext >PreviewMain Section 1 What Is Energy? Chapter What are the small particles that make up matter called? When the particles move faster, they have greater kinetic energy

< BackNext >PreviewMain Section 1 What Is Energy? Other Forms of Energy, continued Chemical Energy is the energy of a chemical compound that changes as its atoms are rearranged. 28. Chemical energy is a form of potential energy because it depends on the position and arrangement of the atoms in a compound. The energy in food is chemical energy. Chapter 9

< BackNext >PreviewMain Section 1 What Is Energy? Other Forms of Energy, continued Electrical Energy is the energy of moving electrons. Electrical energy can be thought of as potential energy that is used when you plug in an electrical appliance and use it. Sound Energy is caused by an object’s vibrations. The object’s vibrations transmit some kinetic energy to the air particles, which also vibrate. These vibrations transmit sound energy. Chapter 9

< BackNext >PreviewMain Section 1 What Is Energy? Other Forms of Energy, continued Light Energy is produced by the vibrations of electrically charged particles. Nuclear Energy is energy that comes from changes in the nucleus of an atom. Nuclear energy can be produced when nuclei are joined in a fusion reaction or when a nucleus is split apart in a fission reaction. Chapter 9

< BackNext >PreviewMain Section 2 Energy Conversions Objectives Describe an energy conversion. Give examples of energy conversions for the different forms of energy. Explain how energy conversions make energy useful. Explain the role of machines in energy conversions. Chapter 9

< BackNext >PreviewMain Section 2 Energy Conversions Kinetic Energy and Potential Energy 29. An energy conversion is a change from one form of energy to another. Any form of energy can change into any other form of energy.. Chapter 9

< BackNext >PreviewMain Section 3 Conservation of Energy 30. The Law of Conservation of Energy states that energy cannot be created or destroyed, it always changes from one form to another. Energy can be converted from one form to another. But all of the different forms of energy in a system always add up to the same total amount of energy. Thermal energy is always released when energy is transferred or converted. Chapter 9

< BackNext >PreviewMain Law of Conservation of energy

< BackNext >PreviewMain Section 2 Energy Conversions Kinetic Energy and Potential Energy, continued Elastic Potential Energy Stretching a rubber band stores elastic potential energy in the rubber band. When you let the rubber band go, it goes back to its original shape. It releases its stored-up potential energy as it does so. Chapter 9

< BackNext >PreviewMain Section 2 Energy Conversions Conversions Involving Chemical Energy Chemical energy is stored in the food you eat. Your body uses this chemical energy to function. Energy Conversion in Plants The chemical energy in the food you eat comes from the sun’s energy. Plants use photosynthesis to convert light energy into chemical energy, as shown on the next slide. Chapter 9

< BackNext >PreviewMain Section 2 Energy Conversions Chapter 9

< BackNext >PreviewMain Section 2 Energy Conversions Conversions Involving Chemical Energy, continued The Process Continues Plants change light energy into chemical energy. The chemical energy in the food you eat is changed into another kind of chemical energy that your body can use. Your body then uses that energy to give you kinetic energy that you use in everything you do. Chapter 9

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< BackNext >PreviewMain Section 2 Energy Conversions Why Energy Conversions Are Important Energy conversions are needed for everything we do. Heating our homes, getting energy from a meal, and many other things use energy conversions. Machines, such as a hair dryer, help harness energy and make that energy work for you. Chapter 9

< BackNext >PreviewMain Section 2 Energy Conversions Why Energy Conversions Are Important, continued 31. Conversions Involving Electrical Energy Some common energy conversions that involve electrical energy are shown in the table below. Chapter 9 Alarm clock electrical energy  light and sound energy Battery chemical energy  electrical energy Light bulb electrical energy  light and thermal energy Blender electrical energy  kinetic and sound energy

< BackNext >PreviewMain Section 2 Energy Conversions Energy and Machines A machine can make work easier by changing the size or direction (or both) of the force needed to do the work. Some machines allow you to use less force over a greater distance to do the same amount of work. Machines as Energy Converters Some machines help you use energy by converting it into the form of energy that you need. Chapter 9

< BackNext >PreviewMain Section 2 Energy Conversions Chapter 9

< BackNext >PreviewMain Section 3 Conservation of Energy Where Does the Energy Go? Friction is a force that oppose motion between two surfaces that are touching. For a roller coaster car to move, energy must be used to overcome the friction between the car’s wheels and the track. As a result, not all of the car’s potential energy changes into kinetic energy and not all of the car’s kinetic energy changes back into potential energy. Chapter 9

< BackNext >PreviewMain Section 3 Conservation of Energy Chapter 9

< BackNext >PreviewMain Section 3 Conservation of Energy Energy Is Conserved Within a Closed System, continued The image below shows energy conservation in a light bulb. Chapter 9

< BackNext >PreviewMain Section 3 Conservation of Energy No Conversion Without Thermal Energy Any time one form of energy is converted into another form, some of the original energy always gets converted into thermal energy. The thermal energy due to friction that results from energy conversions is not usually useful energy. Chapter 9

< BackNext >PreviewMain Section 3 Conservation of Energy No Conversion Without Thermal Energy, continued Perpetual Motion? No Way! A perpetual motion machine is a machine that would run forever without any additional energy. But perpetual motion machines are impossible because some waste thermal energy always results from energy conversions. Chapter 9

< BackNext >PreviewMain Section 3 Conservation of Energy No Conversion Without Thermal Energy, continued Making Conversions Efficient Some systems transform energy with less loss of heat than others do. Such systems are more efficient than others are. Improving the efficiency of machines is important because greater efficiency results in less waste. If less energy is wasted, less energy is needed to operate a machine. Chapter 9

< BackNext >PreviewMain Use the terms below to complete the Concept Mapping on the next slide. Concept Mapping potential energy position mechanical energy motion kinetic energy mass machines Energy and Energy Resources Chapter 9

< BackNext >PreviewMain Energy and Energy Resources Chapter 9

< BackNext >PreviewMain Energy and Energy Resources Chapter 9