| The presence of energy in objects or groups of objects, known as systems. | Energy in Systems |
| How is energy related to systems? | Energy is stored in systems, which can be individual objects or groups of objects. |
| Energy is measured in joules (J), a standard unit of measurement. | Measurement of Energy |
| What unit is used to measure energy? | Energy is measured in joules (J). |
| The principle that energy cannot be created or used up. | Conservation of Energy |
| What is the conservation of energy? | The conservation of energy is the idea that energy cannot be created or destroyed; it can only change forms. |
| Different forms of energy storage within a system, such as kinetic, potential, thermal, chemical, etc. | Energy Stores |
| What are energy stores in a system? | Energy stores are various forms of energy, like kinetic, potential, thermal, and chemical, within a system. |
| The process of energy changing from one form to another when a system undergoes a change. | Energy Transfer |
| What happens when a system changes? | Energy is transferred as the system undergoes a change. |
| The amount of energy transferred during a process or change in a system. | Work Done |
| What is the measure of the amount of energy transferred in a system change? | The amount of energy transferred is often called "work done." |
| Alterations in how energy is stored when systems undergo changes. | Changes in Energy Storage |
| What happens to energy storage during system changes? | There are changes in the way energy is stored when systems change. |
| Various forms of storing energy, including chemical, elastic potential, electrostatic, gravitational potential, kinetic, magnetic, and nuclear. | Types of Energy Storage |
| What are the different energy stores? | Energy can be found in different stores, such as chemical, elastic potential, electrostatic, gravitational potential, kinetic, magnetic, and nuclear. |
| The energy transfers when a person throws a ball, involving changes from chemical energy to kinetic energy to gravitational potential energy. | Work Done in Throwing a Ball |
| Describe the energy transfers when a person throws a ball upwards. | Energy is transferred from the arm's chemical energy store to its kinetic energy store, then to the ball's kinetic energy store. As the ball moves upwards, energy is transferred to its gravitational potential energy store. |
| The energy transfers during the fall of a ball, involving changes from gravitational potential energy back to kinetic energy. | Energy Transfers in Falling Ball |
| What happens to energy as a ball falls? | As the ball falls, energy is transferred from its gravitational potential energy store back to its kinetic energy store. |
| A system where energy cannot enter or leave; it can only be transferred, stored, or dissipated within the objects within the system. | Closed System |
| What defines a closed system? | A closed system is defined by the characteristic that energy cannot enter or leave; it can only be transferred, stored, or dissipated within the objects within the system. |
| The principle stating that energy cannot be created or destroyed in a closed system, and the total amount of energy remains constant. | Conservation of Energy in Closed Systems |
| What is the conservation of energy in closed systems? | Energy cannot be created or destroyed in a closed system; the total amount of energy always remains constant. |
| The concept that in a closed system, there can be no net change in the total amount of energy. | Net Change in Energy |
| What is the principle regarding net change in energy in closed systems? | In a closed system, there can be no net change in the total amount of energy. |
| Considering the entire Universe as a closed system, where energy is constantly transferred among trillions of objects. | Universe as a Closed System |
| How can we conceptualize the Universe in terms of energy? | The entire Universe can be thought of as a closed system, with energy constantly being transferred between trillions of objects, but the total amount of energy in the Universe always stays the same. |
| Diagrams used to represent energy transfers, with boxes symbolizing energy stores and arrows indicating the direction of energy transfer. | Energy Transfer Diagrams |
| How are energy transfers often represented in diagrams? | Energy transfers are often represented using diagrams, where boxes represent energy stores, and arrows indicate the direction of energy transfer. |
| Diagrams composed of arrows of varying widths, with the thickness of the arrow representing the amount of energy transferred. | Sankey Diagrams |
| What is unique about Sankey diagrams in representing energy transfers? | Sankey diagrams use arrows of different widths to represent the amount of energy transferred; thicker arrows indicate more significant energy transfers. |
| The representation of energy efficiency in Sankey diagrams, where thicker arrows indicate more energy transferred usefully. | Energy Efficiency in Sankey Diagrams |
| How is energy efficiency represented in Sankey diagrams? | Thicker arrows in Sankey diagrams indicate more energy transferred usefully, reflecting higher energy efficiency. |
| The dissipation of energy in all system changes, leading to storage in less useful ways or wastage. | Energy Dissipation in System Changes |
| What happens to some energy in all system changes? | In all system changes, some energy is dissipated, stored in less useful ways, or wasted. |
| An equation used to calculate energy efficiency: | Efficiency of Energy Transfer Equation |
| What is the equation to calculate the efficiency of an energy transfer? | The efficiency of an energy transfer is calculated using the equation: Efficiency = (Useful Energy Transferred / Total Energy Supplied) (× 100). |
| The overall efficiency of a system, considering the useful energy transferred and the total energy supplied. | System Efficiency |
| Why are systems never 100% efficient? | Systems are never 100% efficient because only some energy is usefully transferred, while the rest is dissipated. |
| Enhancing the efficiency of energy transfers by reducing the amount of dissipated energy. | Increasing Efficiency |
| How can efficiency be increased in energy transfers? | Efficiency can be increased by reducing the amount of dissipated energy in the system. |
