Triple Physics GCSE AQA Grade 9 Unit 1 Energy Notes
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Course
Science
Institution
GCSE
Physics GCSE AQA Grade 9 Unit 1: Energy notes made by Grade 9 student, now studying A level Chemistry and Biology. Includes all relevant details adhering to the specification and visual aids, such as diagrams, pictures, coloured notes, etc.. Similar quality notes available for all units for each tr...
Unit 1: Energy
Types of Energy
MAGNETIC Energy causing push or pull
+ KINETIC Movement or motion
+ THERMAL/INTERNAL Heat energy (moving particles)
LIGHT Form of energy our eyes can detect
+ GRAVITATIONAL POTENTIAL Energy stored in an object when it is above the earth’s surface
+ CHEMICAL Held in chemical bonds (stored in food and fuel)
SOUND Form of energy we can hear, a vibration transferred from a wave to
produce sound
ELECTRICAL Energy of particles moving through a wire (flow of electrical charge)
+ ELASTIC POTENTIAL Energy stored in objects that are stretched
+ NUCLEAR From breaking atoms apart, stored in atoms’ nuclei
Energy Stores and Systems
System: an object or group of objects.
Closed system: no energy leaves or enters overall.
When this is changed, there are changes in the way energy is stored.
Example:
The cars start high up, with a lot
of Gravitational Potential Energy.
As the car drops, GPE is
transferred into Kinetic Energy.
An electric kettle transfers
electrical energy to thermal
energy.
Diagrams are a useful way to illustrate how the energy is redistributed when a system is
changed.
Example:
This Sankey Diagram shows that an
incandescent light bulb
redistributes the electrical energy
as heat and light.
total energy in = total energy out
, Calculating Energy Changes
Kinetic Energy (moving objects)
2
kinetic energy ( J )=0.5 × mass(kg)× speed (m/ s)
1 2
Ek = m v
2
Gravitational Potential Energy (raising an object above ground level)
gravitational potential energy ( J )=mass ( kg ) × gravitational field strength ( N / Kg ) ×height (m)
E p =mgh
Elastic Potential Energy (the amount of elastic energy stored in a stretched or compressed spring)
elastic potential energy (J )=0.5 × spring constant ( N /m)× extension( m)2
1 2
Ee = k e
2
Specific Heat Capacity and Internal Energy
Internal energy: the total kinetic and potential energy of all the particles that make up a system.
Specific heat capacity: the amount of energy required to raise the temperature of one kilogram of
a substance by one degree Celsius.
change ∈thermal energy ( J )=mass ( kg ) × specific heat capacity ( J /kg ˚ C ) ×temperature change (˚ C )
∆ E=mc ∆ θ
Doing work on a system increases the energy stored in a system.
Heating changes the kinetic energy stored in a system by increasing the heat of the
particles within it.
As the energy increases, this will either increase the temperature or produce a change of
state.
If the temperature increases, the increase depends on:
- The mass of the substance heated
- What the substance is
- The energy input
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