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
Unit 2 Lesson 1 Introduction to Energy Copyright © Houghton Mifflin Harcourt Publishing Company Unit 2 Lesson 1 Introduction to Energy Get Energized! What are two types of energy? • Energy is the ability to cause change. • Energy takes many different forms and causes many different effects. • There are two general types of energy: kinetic energy and potential energy. Copyright © Houghton Mifflin Harcourt Publishing Company Unit 2 Lesson 1 Introduction to Energy What are two types of energy? • Kinetic energy is the energy of an object that is due to motion. All moving objects have kinetic energy. • The amount of kinetic energy an object has depends on its mass and speed. • Kinetic energy increases as mass increases and as speed increases. Copyright © Houghton Mifflin Harcourt Publishing Company Unit 2 Lesson 1 Introduction to Energy What are two types of energy? • Potential energy is the energy that an object has due to its position, condition, or chemical composition. • Potential energy that is the result of an object’s position is called gravitational potential energy. • Gravitational potential energy increases as the object’s height or mass increases. Copyright © Houghton Mifflin Harcourt Publishing Company Unit 2 Lesson 1 Introduction to Energy What are two types of energy? • A change in the condition of an object affects its potential energy. Stretching a rubber band increases its potential energy. • Chemical potential energy depends on chemical composition. • As bonds break and new bonds form between atoms during a chemical change, energy can be released. Copyright © Houghton Mifflin Harcourt Publishing Company Unit 2 Lesson 1 Introduction to Energy Can objects have potential and kinetic energy at the same time? • An object can have both potential and kinetic energy at the same time. • A skater has kinetic energy as he moves down a ramp and potential energy due to his position on the ramp. Copyright © Houghton Mifflin Harcourt Publishing Company Unit 2 Lesson 1 Introduction to Energy In Perfect Form What forms can energy take? • Kinetic energy and potential energy are two types of energy that can come in many different forms. • Some common forms of energy include mechanical, sound, electromagnetic, electrical, chemical, thermal, and nuclear energy. • Energy is expressed in joules (J). Copyright © Houghton Mifflin Harcourt Publishing Company Unit 2 Lesson 1 Introduction to Energy What forms can energy take? • Mechanical energy is the sum of an object’s kinetic energy and potential energy. It is the energy of position and motion. • Sound energy is kinetic energy caused by the vibration of particles in a medium such as steel, water, or air. Copyright © Houghton Mifflin Harcourt Publishing Company Unit 2 Lesson 1 Introduction to Energy What forms can energy take? • Electromagnetic energy is transmitted through space in the form of electromagnetic waves. • These waves are caused by the vibration of electrically charged particles. • Electromagnetic waves include visible light, Xrays, and microwaves. Copyright © Houghton Mifflin Harcourt Publishing Company Unit 2 Lesson 1 Introduction to Energy What forms can energy take? • Electrical energy is the energy that results from the position or motion of charged particles. • Chemical energy is a form of potential energy. • The amount of chemical energy in a molecule depends on the kinds of atoms and their arrangement. Copyright © Houghton Mifflin Harcourt Publishing Company Unit 2 Lesson 1 Introduction to Energy What forms can energy take? • The thermal energy of an object is the kinetic energy of its particles. • The faster the molecules in an object move, and the more particles the object has, the more thermal energy it has. • Heat is the energy transferred from an object at a higher temperature to an object at a lower temperature. Copyright © Houghton Mifflin Harcourt Publishing Company Unit 2 Lesson 1 Introduction to Energy What forms can energy take? • The nucleus of an atom is the source of nuclear energy. • When an atom’s nucleus breaks apart, or when the nuclei of two small atoms join together, energy is released. Copyright © Houghton Mifflin Harcourt Publishing Company Unit 2 Lesson 1 Introduction to Energy Space Weather and Technology • Space weather includes any activity happening in space that might affect Earth’s environment. • Space weather can damage satellites and interrupt phone signals and signals to Global Positioning System (GPS) receivers. • Auroras are caused by electrically charged particles of solar winds hitting Earth’s magnetic field. They can interrupt airplane communications. Copyright © Houghton Mifflin Harcourt Publishing Company Unit 2 Lesson 1 Introduction to Energy Transformers What is an energy transformation? • An energy transformation takes place when energy changes from one form into another form. • Any form of energy can change into any other form of energy. • Often, one form of energy changes into more than one form. Copyright © Houghton Mifflin Harcourt Publishing Company Unit 2 Lesson 1 Introduction to Energy What is an energy transformation? • In a flashlight, chemical energy is transformed into electrical energy. • The electrical energy is then transformed into light and thermal energy. Copyright © Houghton Mifflin Harcourt Publishing Company Unit 2 Lesson 1 Introduction to Energy Is energy conserved? • A closed system is a group of objects that transfer energy only to one another. Energy is conserved in all closed systems. • The law of conservation of energy states that energy cannot be created or destroyed. It can only change forms. • All of the different forms of energy in a closed system always add up to the same total amount of energy. Copyright © Houghton Mifflin Harcourt Publishing Company Unit 2 Lesson 2 Temperature Copyright © Houghton Mifflin Harcourt Publishing Company Unit 2 Lesson 2 Temperature Particle Party What is the kinetic theory of matter? • The kinetic theory of matter states that all of the particles that make up matter are constantly in motion. • Because the particles are in motion, they have kinetic energy. • The faster they move, the more kinetic energy they have. Copyright © Houghton Mifflin Harcourt Publishing Company Unit 2 Lesson 2 Temperature What is the kinetic theory of matter? • The motion of the particles is random. • The individual particles have different amounts of kinetic energy, but their average kinetic energy takes into account their different random motions. • Solids, liquids, and gases have different average kinetic energies. Copyright © Houghton Mifflin Harcourt Publishing Company Unit 2 Lesson 2 Temperature How do particles move in solids, liquids, and gases? • The kinetic theory of matter explains the motion of particles in solids, liquids, and gases. • The particles in a solid do not move around much. Copyright © Houghton Mifflin Harcourt Publishing Company Unit 2 Lesson 2 Temperature How do particles move in solids, liquids, and gases? • The particles in a liquid move much more freely than the particles in a solid. They slide past and tumble over each other. Copyright © Houghton Mifflin Harcourt Publishing Company Unit 2 Lesson 2 Temperature How do particles move in solids, liquids, and gases? • The particles in a gas are far apart, move at high speeds, and collide with one another. Copyright © Houghton Mifflin Harcourt Publishing Company Unit 2 Lesson 2 Temperature Mercury Rising How does temperature relate to kinetic energy? • Temperature is a measure of the average kinetic energy of all the particles in an object. • The warmer a substance is, the faster its particles move. Copyright © Houghton Mifflin Harcourt Publishing Company Unit 2 Lesson 2 Temperature How is temperature measured? • There are three common temperature scales. • They all measure the average kinetic energy of particles. • The scales are called Celsius, Fahrenheit, and Kelvin. Copyright © Houghton Mifflin Harcourt Publishing Company Unit 2 Lesson 2 Temperature How is temperature measured? • In the Celsius and Fahrenheit scales, temperature is measured in units called degrees. • Degrees (°) are equally spaced units between two points. The space between degrees can vary from one scale to another. • In the Kelvin scale, no degree sign is used. The unit is just called a kelvin. • Temperature is measured with a thermometer. Copyright © Houghton Mifflin Harcourt Publishing Company Unit 2 Lesson 2 Temperature How is temperature measured? • The Celsius scale is the temperature scale most commonly used around the world. Copyright © Houghton Mifflin Harcourt Publishing Company Unit 2 Lesson 2 Temperature How is temperature measured? • The Fahrenheit scale is used most commonly in the United States. Copyright © Houghton Mifflin Harcourt Publishing Company Unit 2 Lesson 2 Temperature How is temperature measured? • The Kelvin scale is used most commonly by physicists. Copyright © Houghton Mifflin Harcourt Publishing Company