P1: Energy
Physics Unit 1: Energy
GCSE Revision Notes
You cannot directly observe energy; you can observe its effects but not the energy itself.
Law of conservation of energy: Energy cannot be created or destroyed it can be transferred usefully
from one store to another in a closed system or dissipated, but the total amount of energy remains
the same.
Closed system: A system is a word used to describe a single object or a group of objects that you are
interested in. A closed system is a region or group of objects from which neither matter nor energy
can enter or leave. For a closed system, the total amount of energy is constant.
Types of energy: Sometimes we use names for energy, such as electrical, kinetic or gravitational
potential. Actually, it's more useful to identify where the energy is because it tells us more. We can
then work out how it's been transferred. For example, chemical energy stored in a battery can be
usefully transferred into kinetic energy in a hand-held fan, some thermal energy is wasted as heat
which is dissipated into the surrounding air. The energy is transferred as electrical energy.
Energy stores:
Transfers of energy: Energy can be transferred between different stores using these four different
methods listed below. As stated above in the law of conservation of energy, energy cannot be
created or destroyed, but it can be transferred from one store to another or dissipated. For example,
a hairdryer uses electrical energy to transfer energy into the thermal and kinetic energy stores of the
1
, P1: Energy
air that is moving. There is some wasted kinetic energy that is detected by our ears as a vibration in
the air.
Methods of energy transfer:
Example 1 – an object being thrown upwards: Energy is being transferred from the kinetic store
(movement) to the gravitational store.
Example 2 – a moving car hitting an object: Energy is being transferred from the kinetic store to the
thermal store.
2
Physics Unit 1: Energy
GCSE Revision Notes
You cannot directly observe energy; you can observe its effects but not the energy itself.
Law of conservation of energy: Energy cannot be created or destroyed it can be transferred usefully
from one store to another in a closed system or dissipated, but the total amount of energy remains
the same.
Closed system: A system is a word used to describe a single object or a group of objects that you are
interested in. A closed system is a region or group of objects from which neither matter nor energy
can enter or leave. For a closed system, the total amount of energy is constant.
Types of energy: Sometimes we use names for energy, such as electrical, kinetic or gravitational
potential. Actually, it's more useful to identify where the energy is because it tells us more. We can
then work out how it's been transferred. For example, chemical energy stored in a battery can be
usefully transferred into kinetic energy in a hand-held fan, some thermal energy is wasted as heat
which is dissipated into the surrounding air. The energy is transferred as electrical energy.
Energy stores:
Transfers of energy: Energy can be transferred between different stores using these four different
methods listed below. As stated above in the law of conservation of energy, energy cannot be
created or destroyed, but it can be transferred from one store to another or dissipated. For example,
a hairdryer uses electrical energy to transfer energy into the thermal and kinetic energy stores of the
1
, P1: Energy
air that is moving. There is some wasted kinetic energy that is detected by our ears as a vibration in
the air.
Methods of energy transfer:
Example 1 – an object being thrown upwards: Energy is being transferred from the kinetic store
(movement) to the gravitational store.
Example 2 – a moving car hitting an object: Energy is being transferred from the kinetic store to the
thermal store.
2
