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Paper 1 - Coggle Diagram
Paper 1
Energy Changes in a system
A system is an object or group of objects
In a closed system, no energy transfers take place into or out of the stores
Stores
Chemical
Kinetic
Gravitational potential
Elastic potential
If an object regains its original shape after being stretched or squashed
Thermal energy
Pathways
Heating
electrical current
mechanical
waves
Conservation of energy
Energy can not be created nor destroyed
Only transferred from one store to another
Work done
Force x distance
Joules / J
When a force moves an object, energy is transferred to the object
If an object doesn't move, no work is done
Wasted energy
dissipates to the surroundings heating it up
as the energy spreads out it becomes less useful
Efficiency
No device can be more efficient than 100%
Efficiency can be improved by:
using lubrication
copper wires minimise electrical resistance
shapes of objects are made more streamlined (to reduce air resistance)
Specific Heat Capacity
The energy needed to raise 1kg of a substance by 1 degree C
Molecules and Matter
Density
States of matter
Solid
the particles vibrate about fixed positions
Highest density
Liquid
Particles are in contact
Move at random
Gas
Particles are far apart
Particles move at random
Lowest density
Specific Latent Heat
Latent heat of fusion
the energy needed to change 1kg of a substance from a solid to a liquid
No change in temperature
Latent heat of vaporisation
the energy needed to change 1kg of the substance from a liquid to a vapour
No change in temperature
a joulemeter is used to measure the energy change
latent heat is the energy needed for a substance to change state
Internal Energy
Total energy in the kinetic store and the potential energy store of the particles
the kinetic energy is the motion of the particles
If the kinetic store of the particles increase, the temperature of the substance increases
the potential energy is the due to the particles position to each other
If a substance changes state, the potential energy of its particles increases
Energy Transfers
As an electrical charge flows through an appliance, electrical energy is transferred by the appliance to another store
The rate which the energy transfers is called power
The p.d. of the mains supply is 230V
An electric current is a flow of charge
When charge flows through a resistor, energy is transferred to the resistor
The thermal energy store of the resistor increases and it becomes hotter
This thermal energy is transferred to the surroundings