IGCSE O’level Physics
Topic 4
Energy Stores & Transfers
Energy can be stored in different ways, and there are changes in the way it is
stored when a system changes
There are many different ways that energy can be stored, these are shown in the
table below:
Types of Energy Stores Table
A system can change between stores through different energy transfer
mechanisms
, Examples of these are:
o Mechanical
o Electrical
o Heating
o Radiation
These are described in the table below:
Types of Energy Transfers Table
An example of a thermal energy transfer is a hot coffee heating up cold hands
,Q-1 : Describe the energy transfers in the following scenarios:
a) A falling object
b) A battery powering a torch
c) A mass on a spring
For a falling object:
Energy is transferred from the gravitational store to the kinetic store of the object via
a mechanical transfer pathway
For a battery powering a torch:
Energy is transferred from the chemical store of the battery to the thermal store of the
surroundings via a radiation transfer pathway
For a mass on a spring:
Energy is transferred from the elastic store to the kinetic store of the system via
a mechanical transfer pathway
The Conservation of Energy
Energy is the capacity of something to do work:
o If something contains a store of energy it is able to do work
o If something does not store energy then it will not work
The law of conservation of energy states that:
o Energy cannot be created or destroyed, it can only change from one form to
another
This means the total amount of energy in a closed system remains constant but can
change where, and how, it is stored
Energy can therefore not necessarily be 'lost', but just transferred into wasted
energy (often heat)
Conservation of energy applies to all energy systems
, Some examples:
A falling object (in a vacuum): Gravitational potential energy → Kinetic energy
A gas cooker: Chemical → Internal (Heat)
An LED (Light Emitting Diode): Electrical → Light
Example 1: A Television
The energy changes in televisions are:
electrical energy ➝ light energy + sound energy + thermal energy
Light and sound energy are useful energy transfers whereas thermal energy (from the
heating up of wires) is wasted
Useful and wasted energy conversions for a television
Example 2: Heaters
The energy changes in an electrical heater:
electrical energy ➝ thermal energy + sound energy + light energy
Topic 4
Energy Stores & Transfers
Energy can be stored in different ways, and there are changes in the way it is
stored when a system changes
There are many different ways that energy can be stored, these are shown in the
table below:
Types of Energy Stores Table
A system can change between stores through different energy transfer
mechanisms
, Examples of these are:
o Mechanical
o Electrical
o Heating
o Radiation
These are described in the table below:
Types of Energy Transfers Table
An example of a thermal energy transfer is a hot coffee heating up cold hands
,Q-1 : Describe the energy transfers in the following scenarios:
a) A falling object
b) A battery powering a torch
c) A mass on a spring
For a falling object:
Energy is transferred from the gravitational store to the kinetic store of the object via
a mechanical transfer pathway
For a battery powering a torch:
Energy is transferred from the chemical store of the battery to the thermal store of the
surroundings via a radiation transfer pathway
For a mass on a spring:
Energy is transferred from the elastic store to the kinetic store of the system via
a mechanical transfer pathway
The Conservation of Energy
Energy is the capacity of something to do work:
o If something contains a store of energy it is able to do work
o If something does not store energy then it will not work
The law of conservation of energy states that:
o Energy cannot be created or destroyed, it can only change from one form to
another
This means the total amount of energy in a closed system remains constant but can
change where, and how, it is stored
Energy can therefore not necessarily be 'lost', but just transferred into wasted
energy (often heat)
Conservation of energy applies to all energy systems
, Some examples:
A falling object (in a vacuum): Gravitational potential energy → Kinetic energy
A gas cooker: Chemical → Internal (Heat)
An LED (Light Emitting Diode): Electrical → Light
Example 1: A Television
The energy changes in televisions are:
electrical energy ➝ light energy + sound energy + thermal energy
Light and sound energy are useful energy transfers whereas thermal energy (from the
heating up of wires) is wasted
Useful and wasted energy conversions for a television
Example 2: Heaters
The energy changes in an electrical heater:
electrical energy ➝ thermal energy + sound energy + light energy
