PHY - Energy transfers

8 energy stores

gravitational potential G

elastic E

nuclear N

thermal T

magnetic M

electrostatic E

chemical C

kinetic K

4 energy transfers + examples

Mechanical - friction, transferred from kinetic to thermal store

radiation - suns rays, nuclear to thermal store

electrical - electric car, transferred from chemical to kinetic

heating - kettle, chemical to thermal store

Gravitational Potential Energy

Energy stored in an object due to it’s height

Elastic Energy

Energy stored in an object when it is compressed or stretched.

Nuclear Energy

Energy stored in the nucleus of an atom (nuclei)

Thermal Energy

Energy stored in hot objects

Magnetic Energy

Energy stored in the magnetic fields of 2 objects

Electrostatic Energy

Energy stored in the movement of electrons

Chemical Energy

Energy stored in chemical reactions e.g. food, batteries

Kinetic Energy

Energy stored in a moving object

Mechanical Energy Transfer

Transfer of energy through mechanical means, such as movement.

Radiation Transfer

Transfer of energy through the radiation of light

Electrical Energy Transfer

Transfer of energy through electric charges

Heating Transfer

Transfer of energy when the temp. of an object increases

measurement of energy

Joules, J

principle of conservation

energy cannot be destroyed or made only transferred

useful energy

the energy that is transferred to the place where it is wanted, in the form that it is needed

wasted energy

energy that is not useful for the intended purpose and therefore dissipates to the surroundings

how to calculate efficiency

useful energy output

——————————

total energy input

bouncy ball method

1 - release a ball from a measured height above the floor e.g. 1m, and measure the height it rebounds too using a metre ruler

2 - repeat the measurements for the same initial height using the same type of ball

3 - record the measurements and calculate the average/ mean height reached by the ball

4 - workout the efficiency of the bounce (height reached ÷ inital height )

6 - repeat test with different balls

what 3 forms of energy are most likely wasted

heat/ thermal

sound

light

reduce wasted energy: friction between moving objects

adding lubricant

reduce wasted energy: resistance of a wire causing it to get hot

use wires with a lower resistance

cooling systems

reduce wasted energy: air resistance as an object moves

aerodynamics/ streamlined

reduce surface area

reduce wasted energy: sound energy created by machines

sound insulation

reduce friction