Energy Flashcards
What is energy?
Energy is the ability to do work. It is measured in Joules (J).
Conservation of energy
The principle of conservation of energy states that energy cannot be created or destroyed.
It can only be transferred from one store to another.
Energy stores:
Kinetic energy
Gravitational potential energy
of
Chemical energy
Elastic potential energy
Magnetic Potential Energy
Electrostatic Energy
Nuclear Energy
Thermal energy
Kinetic energy
All moving things have kinetic energy. It increases with the mass and speed of the object.
Gravitational potential energy
This is the potential to fall. It is larger when an object is higher. It can be transferred to kinetic energy if the object falls.
Chemical energy
Stored in chemical bonds (eg. petrol, batteries, food)
Electrostatic potential energy
Charged objects attract or repel each other due to the electric field that charges create around them. Insulators get electrically charged and attract light objects (eg. hair).
Magnetic energy
Found between two magnetic objects, due to the magnetic field created around them.
Elastic potential energy
On stretched or compressed objects, when you let go, this energy will be transferred into kinetic energy (eg. with a slingshot)
Nuclear energy
Found when radioactive substances decay (e.g. Uranium), nuclei are split (fission) or joined together (fusion).
Thermal energy
Contained in hot objects. The hotter the object the more energy in its thermal energy store.
What is absolute zero?
It is the state measured in Calvin’s, when two gases can compress to give nothing, defying the laws of energy conservation. This is about -270 degrees Celsius.
Energy Transfers
Heating
Electric current
Radiation
Mechanical
Heating
Energy is transferred due to a temperature difference, from hot to cold.
Electric current
Flow or movement of electrons
