P1 - Energy (incomplete)

Energy stores

thermal, kinetic, gravitational potential, elastic potential, chemical, magnetic, electrostatic, nuclear

Thermal

objects with heat

Kinetic

moving objects

Gravitational potential

objects at a height

Elastic potential

objects being stretched or squeezed

Chemical

stored in the bonds between atoms and molecules

Magnetic

stored when repelling forces are pushed together or attracting forces are pulled apart

Electrostatic

stored when repelling charges are pushed together or attracting charges are pulled apart

Nuclear

stored in the nucleus of an atom

Pathways

mechanically, electrically, by heating, by radiation

Mechanically

by a force doing work

Electrically

by moving charges

By heating

by temperature difference caused by electrical or chemical reaction

By radiation

by light or sound

System

an object or group of objects you’re interested in

Closed system

net change in total energy is always 0

Specific heat capacity

Energy required to raise the temperature of 1kg of a substance by 1°C

Conservation of energy

Energy cannot be created or destroyed, only transferred or dissipated

Conduction

Process where vibrating particles transfer energy to neighboring particles

Conduction steps

1. Particles in the hot part of the object begin to vibrate faster, colliding with each other

2. Collisions cause energy transfer between kinetic stores

3. The process continues until particles in the cold part of the object also move faster

4. Any other energy is transferred to the thermal stores of the surrounding air

Thermal conductivity

Measure of how quickly energy is transferred through the material

Convection

(Fluids) Process where particles move away from hotter regions to cooler regions

Convection steps

1. Particles in fluids are able to move around

2. The particles which are heated move faster and space between particles increases, which causes the density to decrease

3. The less dense regions will rise above the cooler, denser regions

4. If the cooler particles are now heated, this creates a convection current