Chapter 1: Energy Transfers
1.1: Energy Stores and Transfers
Energy Stores
· Energy store: Where the energy transferred to that object is stored (like a “bucket” of energy that it
can be “poured into or taken out of”).
· Different types of energy store and objects with energy in these stores:
-Kinetic: Something that is moving has energy in its kinetic energy store.
-Thermal: The hotter an object is the more energy it has in its thermal energy store. This can be any
object (thermal energy stores can also be called “internal energy stores”).
-Chemical: Anything that can release energy by a chemical reaction has a chemical energy store.
-Gravitational Potential: Anything that has mass and is inside a gravitational field has a Gravitational
Potential store.
-Elastic Potential: Anything that is stretched or compressed.
-Electrostatic: Anything with an electric charge that is interacting with another electric charge.
-Magnetic: Anything magnetic that is interacting with another magnet.
-Nuclear: Nuclei in atoms have energy in this store that can be released in nuclear reactions.
Energy transfers
· System: word for a single object or a group of objects that are the main subject(s) of interest.
· Closed system: systems where neither matter nor energy can enter or leave. The net change in the
total energy of a closed system is always zero.
· When a system changes, energy is transferred. It can be transferred into or away from a system,
between different objects in the system, or between various kinds of energy stores.
· Different ways that energy can be transferred between stores in four main ways:
-Mechanically: an object moving due to a force acting on it.
-Electrically: a charge (current) moving through a potential difference.
-By heating: energy transferred from a hotter object to a colder object.
1.1: Energy Stores and Transfers
Energy Stores
· Energy store: Where the energy transferred to that object is stored (like a “bucket” of energy that it
can be “poured into or taken out of”).
· Different types of energy store and objects with energy in these stores:
-Kinetic: Something that is moving has energy in its kinetic energy store.
-Thermal: The hotter an object is the more energy it has in its thermal energy store. This can be any
object (thermal energy stores can also be called “internal energy stores”).
-Chemical: Anything that can release energy by a chemical reaction has a chemical energy store.
-Gravitational Potential: Anything that has mass and is inside a gravitational field has a Gravitational
Potential store.
-Elastic Potential: Anything that is stretched or compressed.
-Electrostatic: Anything with an electric charge that is interacting with another electric charge.
-Magnetic: Anything magnetic that is interacting with another magnet.
-Nuclear: Nuclei in atoms have energy in this store that can be released in nuclear reactions.
Energy transfers
· System: word for a single object or a group of objects that are the main subject(s) of interest.
· Closed system: systems where neither matter nor energy can enter or leave. The net change in the
total energy of a closed system is always zero.
· When a system changes, energy is transferred. It can be transferred into or away from a system,
between different objects in the system, or between various kinds of energy stores.
· Different ways that energy can be transferred between stores in four main ways:
-Mechanically: an object moving due to a force acting on it.
-Electrically: a charge (current) moving through a potential difference.
-By heating: energy transferred from a hotter object to a colder object.
