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B6 Energy transformations and energy transfers - Coggle Diagram
B6 Energy transformations and energy transfers
Types of energy
Elastic
: the energy of a stretched spring or elastic band. (sometimes called strain energy)
Chemical
: the energy contained in a chemical substance
Gravitational potential
: the energy that gains when you lift it up, and which it loses when it falls
Nuclear
: the energy containd within the nucleus of an atom
Kinetic
: the energy of a moving object
Internal
: the energy something has due to its temperature (or state). (Sometimes referred to as thermal or heat energy
Energy transfer
In addition to the six forms of energy mentioned above, there are four ways in which energy can be transferred from one form to another:
Electrical currents
(electrical working): electricity can transfer energy from a power source, delivering it to components within a cirucit
Heating
: internal energy can be transdered from place to place by the processes of conduction, convection and radiation
Forces
(mechanical working): when a force acts on a body, energy can be tranferred between two forms
Waves
: light and sound carry energy and so can transfer it between places
Energy dissipation
When energy is transferred from one form to another, not all of the energy will end up in the desired form (or place)
This lost energy often ends up being dissipated (spreading out into the environment), usually in the form of heat, light or sound
The conservation of energy
Energy is the capacity of something to do work:
If something contains a store of energy it is able to do work
If something does not store energy then it will not work
The law of conservation of energy states that:
Energy cannot be created or destroyed, it can only change from one form to another
What this means is that the total amount of energy in a closed system remains constant, although how much of each form there is may change
Many processes involve several steps before energy ends up in its final form
Efficient and inefficient systems
Whenever energy is transferred from one form to another, some of that energy is usually wasted and is transferred away from the system, usually in the form of heat or waves (light and sound)
An efficient system is one where most of the energy going into that system ends up in the form that is wanted
The efficiency of a system is the percentage of energy transferred from the original store that ends up in the intended form
Efficiency = useful energy output ÷ total energy input x 100%
Gravitational potential energy
The gravitational potential energy (GPE) of an object is the energy it has due to its height in a gravitational field:
If an object is lifted up it will gain GPE
If it falls, it will lose GPE
The GPE of an object is related to its mass (m), height (h) and the gravitational field strength (g):
GPE = mass x gravity x height.
GPE: m x g x h
Kinetic energy
The kinetic energy (KE) of an object is the energy it has as a result of its speed
It is related to the mass (m) and speed (v) of the object
kinetic energy: 1/2 x mass x speed²
KE = 1/2 x m x v²
Descriptions and forms
Geothermal: internal energy
Nuclear fission: nuclear energy
Waves: kinetic energy
Solar heating: light energy.
Water: gravitational potential energy
Solar cells: light energy
Fuels: chemical energy.
Wind: kinetic energy
A renewable energy resource is one that is replenished at a faster rate than the rate at which it is being used
As a result of this, renewable energy resources cannot run out
Work done
Energy is the capacity of something to do work
Work is done whenever a force acts on an object that moves (or is moving) in the direction of the force
The greater the force, the greater the work
The larger the distance moved, the larger the work
The amount of energy transferred (in joules) is equal to the work done (also in joules)
Usually, if a force acts in the direction that an object is moving then the object will gain energy
If the force acts in the opposite direction to the movement then the object will lose energy
work done = force × distance moved
W = F× d