Chapter 8 Note-taking Guide Forms of energy Energy transfers and transformations Particles in Motion

Define energy, and provide examples of its influences The ability to cause change. Climate Energy drives storms. Economy Fuels provide the energy needed to power vehicles and transport goods. Politics Politicians discuss policies related to new energy resources.

Describe potential energy Stored energy due to the interaction between objects or particles Gravitational Depends on an object’s mass and height above Earth’s surface Chemical Energy stored in and released from the bonds between atoms. Nuclear Energy stored in and released from the nucleus of an atom.

Differentiate potential energy and kinetic energy. Stored energy due to the interaction between objects or particles Kinetic energy Energy due to motion

Relate kinetic energy to mass and speed of objects. No speed No kinetic energy Greater mass Greater kinetic energy Greater speed

Explain why electric energy is a form of kinetic energy. Electric energy is the motion of flowing electrons.

Model a system and an environment Model a system and an environment. Define each term, and label the part of the diagram that represents each term. System A collection of interacting objects, parts, or ideas that work together as a whole. Environment Everything that is not in the system.

Compare and contrast mechanical energy and thermal energy. Both Thermal Energy The sum of the potential energy and the kinetic energy in a system The sum of potential energy and kinetic energy The sum of the energy of the particles that make up an object

Wave: A disturbance. does not move matter. does move energy from one place to another. moves in which direction? outward.

Identify two types of energy carried by waves. Type of Energy Carried By Moves Through Sound energy sound waves matter Radiant energy electromagnetic waves matter and space without matter

Connect It Relate every form of energy mentioned in Lesson 1 to at least one other energy form. Three types of potential energy are gravitational potential, chemical and nuclear energy. Electric energy is a form of kinetic energy. Both mechanical and thermal energy represent the combinations of potential and kinetic energy. Both sound and radiant energy are carried by waves.

NGSSS Check What is the law of conservation of energy? The law of conservation of energy says that energy transformations conserve energy and neither create nor destroy it.

Express the law of conservation of energy in a diagram can be transformed from one form to another. cannot be created or destroyed.

Apply the law of conservation of energy to energy transformations that occur in a flashlight. Chemical energy from the battery electric energy moving through the contact strip to the bulb radiant energy + thermal energy in the bulb transformed to transformed to

NGSSS Check Identify an energy transfer and an energy transformation that occurs when someone plays a guitar. Chemical energy is a person’s cells is transformed to mechanical energy in the fingers Mechanical energy is then transferred to the guitar strings Mechanical energy from the guitar strings is transformed into sound energy and elastic energy

Contrast energy transfer with energy transformation Energy moves without changing form. Energy changes form as it moves.

Identify three criteria required for an energy transfer to be considered an occurrence of work. A force makes an object move. The motion is in the direction of the force. The object moves while the force is acting on it.

Explain what makes an energy transformation inefficient. Not all of the energy is transformed to a usable form of energy.

Distinguish an open system from a closed system. Definition: A system that exchanges matter or energy with the environment. Example: A car engine. Explanation: Thermal energy and sound energy are released into the environment. Definition: A system that does not exchange matter or energy with the environment. Example: None exist. Explanation: Scientists use the idea to study and model the movement of energy.

Categorize resources that people transform into electric energy. Category Definition Types Renewable energy resource An energy resource that is replaced as fast as, or faster than, it is used Solar Wind Hydroelectric Geothermal Biomass Nonrenewable energy resource An energy resource that is available in limited amounts, or that is used faster than is can be replaced in nature Fossil fuels Nuclear energy

Synthesize It Explain two reasons it is wise to use energy-efficient electric appliances. Some energy is already lost in every transformation; more energy is put into a device than the work we get out of the device. Also, a majority of our electricity comes from nonrenewable resources, so it is smart to use it sparingly and to make it last.

Record 3 major points of the kinetic theory. All matter is made of particles (atoms). Particles are in constant, random motion. Particles constantly collide with each other and the walls of their container.

Relate temperature to thermal expansion. When temperature Increases, the average kinetic energy of particles increases Thermal expansion occurs when particles collide more often and push each other farther apart

Differentiate temperature and heat Differentiate temperature and heat. Circle the word in each definition that most distinguishes the meaning of the term. Temperature The measure of the average kinetic energy of the particles in a material Heat The movement of thermal energy from a region of higher temperature to a region of lower temperature

Identify and describe the condition under which two materials in contact would each have temperature but no heat. The condition is called thermal equilibrium. If the temperatures of two materials are the same, kinetic energy does not move (as heat) from one to another.

Describe 3 ways in which thermal energy is transferred. Method Description Conduction The transfer of thermal energy due to collisions between particles in matter Radiation The transfer of thermal energy by electromagnetic waves Convection The transfer of thermal energy by the movement of the particles from one part of a material to another

Characterize the relationship between heat and typical changes of state. Add enough thermal energy to a solid… It melts, or becomes a liquid Remove enough thermal energy from a liquid… It freezes, or becomes a solid Vaporization, or the change from liquid to gas, occurs. Add enough thermal energy to a liquid… Condensation, or the change from gas to liquid, occurs. Remove enough thermal energy from a gas…

Differentiate types of vaporization. Two Types of Vaporization Boiling occurs within liquid Evaporation occurs at surface Identify which of the processes above requires an addition of thermal energy. Both

Distinguish sublimation from deposition Distinguish sublimation from deposition. Circle the process that represents an increase in thermal energy. Sublimation Deposition Solid changes to gas without going through a liquid state. Gas changes to solid without going through a liquid state.

Contrast the ability of materials to transfer thermal energy. Energy transfer: Quick Reason: Electrons are free to move Thermal conductor Energy transfer: Slow Reason: Electrons are held tightly in place Thermal insulator

Connect It Describe the thermal energy transfers between particles that occur when you overheat some soup for lunch, then drop an ice cube in it to cool it off. Heat transfers from the stove burner to the pan holding the soup by conduction. Heat transfers within the soup by convection, causing it to boil. After adding the ice cube, heat transfers from the soup to the ice, causing the ice to melt and become water. The soup continues to cool and the water (formerly ice) continues to heat up until both liquids are at thermal equilibrium.

Summarize It Reread the Think About It question and the lesson Key Concepts. Summarize what you have learned by converting two of the Key Concept questions from each lesson into factual answers. Lesson 1 Potential energy and kinetic energy differ in that objects (and particles) with kinetic energy are in motion Kinetic energy and thermal energy are similar in that they both represent the sum of potential and kinetic energy.

Summarize It Reread the Think About It question and the lesson Key Concepts. Summarize what you have learned by converting two of the Key Concept questions from each lesson into factual answers. Lesson 2 The law of conservation of energy says that energy can be transformed from one form to another, but it cannot be created or destroyed. Renewable energy resources can be replaced as quickly as they are used. Nonrenewable energy resources are used faster than they can ever be replaced.

Summarize It Reread the Think About It question and the lesson Key Concepts. Summarize what you have learned by converting two of the Key Concept questions from each lesson into factual answers. Lesson 3 Kinetic theory says that all matter is made up of particles that are in constant, random motion and constantly collide with each other and the walls of their container. Thermal energy is transferred through conduction, convection and radiation.