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P1.1.4 Heating and insulating buildings
P1.1 Heating processes
KINETIC
THEORY
Arrangement
Movement
SOLIDS
Increasing energy 
LIQUIDS
Particles close
together in
regular pattern
Vibrate about a
fixed position
Particles close
together but
random positions
Move around
each other
GASES
Particles far
apart and random
Move quickly in
random directions
Diagram
Specific heat capacity (s.h.c.)
U-values
U-values measure how effective The specific heat capacity is the amount of energy(J)
required to change the temperature of 1 kg of the substance
a material is as an insulator.
The lower the U-value the
by 1C.
better the insulator.
E (J) = m (kg) x c (J/kgC) x  (C)
Energy = mass x s.h.c. x temperature change
Payback time
Payback time is a measure of how cost-effective an energy saving solution is.
payback time (years) = cost of installation (£) ÷ savings per year in fuel costs (£)
P1.2 Energy and efficiency
Energy
Energy can be transferred usefully, stored, or dissipated
(spreads out), but cannot be created or destroyed.
Wasted energy
When energy is transferred only part of it may be usefully
transferred, the rest is ‘wasted’.
Wasted energy is eventually transferred to the surroundings,
which become warmer. The wasted energy dissipates and so
becomes less useful.
Solar panels
Solar panels may contain water that is heated by the Sun. This may then be used to heat
buildings or provide hot water.
Radiation
Conduction
All objects emit
Particles in a material can
transfer heat by colliding and
infrared radiation.
The hotter the
object the more
radiation it emits.
Dark, matt
surfaces are good
absorbers AND
transferring kinetic energy
trough material. Non-metals
Convection
When heated, particles
move faster. This means
and gases are poor conductors they take up a larger
(insulators) metals are good
volume. This means
conductors (due to free
hotter liquid/gas is less
electrons).
emitters. Light,
Free electrons
shiny surfaces are In metals electrons can move
away from the ions. When the
poor absorbers
AND emitters
metal gets hot, the ions gain
because they are
good reflectors.
kinetic energy and vibrate
densethan cooler
liquid/gas which means
it rises and the cooler
liquid/gas falls to
replace it.
more. The kinetic energy is
transferred from the hot part
to the cooler part by the free
electrons moving through the
metal and colliding with ions.
EVAPORATION
CONDENSATION
Liquid changes to a gas
Gas changes to a liquid
The particles in a liquid have
different energies. Some will
have enough energy to escape
from the liquid and become a
gas. The remaining particles in
the liquid have a lower average
kinetic energy than before, so
the liquid cools down as
evaporation happens.
The particles in a gas have
different energies. Some may
not have enough energy to
remain as separate particles,
particularly if the gas is cooled
down. They come close together
and bonds form between them.
Energy is released when this
happens.
Rate of heat energy transfer
Increasing these factors increases the rate of heat energy transfer:

Temperature difference between object and surroundings

Surface area
Changing the material or the nature of the surface the object is touching
can also affect the rate of energy transfer.
Core Physics (P1)
Happens in liquids and
gases.
P1.4 Generating electricity
How a power station works
Possible energy sources
Fossil fuels (coal, oil, gas)
Produces steam
Turbine in coupled
source used
Biofuels
which drives a
to electrical
to heat
Nuclear
c turbine
c generator
water
Geothermal
v – energy sources thatvare naturally
Renewable energy
Water and wind can be used
replenished on a human timescale.
to drive turbines directly (no
Examples: solar, wind, tidal, hydroelectric, geothermal,
steam)
biofuel (NOT fossil fuels or nuclear)
Solar cells can turn Sun’s
Environmental effects
radiation directly into
The effects of using different energy sources include:
electricity (no power station)

The release of substances into the atmosphere

The production of waste materials

Noise and visual pollution

The destruction of wildlife habitats
Energy
Carbon dioxide (and other greenhouse gases)
The build up of these gases in the atmosphere causes global warming.
To reduce this, we can catch and store carbon dioxide using carbon capture.
Electricity is distributed from power stations
to consumers along the National Grid.
Efficiency
𝐞𝐟𝐟𝐢𝐜𝐢𝐞𝐧𝐜𝐲 =
𝐮𝐬𝐞𝐟𝐮𝐥 𝐞𝐧𝐞𝐫𝐠𝐲 𝐨𝐮𝐭
(× 100%)
𝐭𝐨𝐭𝐚𝐥 𝐞𝐧𝐞𝐫𝐠𝐲 𝐢𝐧
x100% to turn
from a decimal
𝐞𝐟𝐟𝐢𝐜𝐢𝐞𝐧𝐜𝐲 =
𝐮𝐬𝐞𝐟𝐮𝐥 𝐩𝐨𝐰𝐞𝐫 𝐨𝐮𝐭
(× 100%)
𝐭𝐨𝐭𝐚𝐥 𝐩𝐨𝐰𝐞𝐫 𝐢𝐧
percentage
into a
P1.3 Electrical appliances
Energy forms
kinetic (movement)
choice of appliance depends thermal (heat)
on its efficiency and cost
light
effectiveness.
gravitational potential
Energy transferred depends chemical (e.g. in batteries)
on how long the appliance is sound
switched on and its power.
electrical
E (J) = P (W) x t (s)
elastic potential
energy = power x time
Appliances transfer energy
into different forms. The
P1.4.2 The National Grid
Step-up transformers increase
the voltage that the electricity is
transmitted at. Very high voltage
reduces the current required
which reduces the energy losses.
Step-down transformers reduce
Supply and demand
In order to meet demands on
electricity we must use
reliableenergy sources.
Coal or nuclear can be used to supply
the ‘base load’ (they are run all the
time) because they take a long time
to start up. Oil or gas can be used
the voltage so that the electricity
for extra electricity at peak times
is safe for domestic use.
because they are quick to start up.
General properties of waves
ALL WAVES TRANSFER ENERGY.
Key words
P1.5.4 Red shift
P1.5 Waves
Amplitude (a)– distance from the equilibrium position
(centre line) to the top of a crest or bottom of a trough,
measured in metres
Frequency (f)– the number of waves passing a point each
second, measured in Hz
Wavelength ()– distance from the top of one crest to
the top of the next crest, measured in metres
Wave speed (v) – how far the wave travels in a certain
time, measured in metres per second.
TRANSVERSE WAVES
Oscillations are perpendicular to the
direction of energy transfer.
LONGITUDINAL WAVES
Oscillations are parallel to the direction of energy
transfer.
a change in the observed wavelength and frequency.
Can happen with any wave, for example:
- Sound
- Light
Examples:

Electromagnetic waves (light,
infrared, microwaves ect.)

S waves

Mechanical waves

Water waves
Examples:

Sound waves

P waves

Mechanical waves

Water waves
Sound
Sound waves longitudinal waves that cause vibrations in a medium (e.g. air).
Pitch - The pitch of a sound is determined by frequency.
High pitch
High frequency
Low pitch
Low frequency
Volume - The volume of a sound is determined by amplitude.
The wave equation
Low volume
Low amplitude
v (m/s) = f (Hz) x  (m)
wave speed = frequency x wavelength
Electromagnetic waves
All electromagnetic waves travel at the same speed (the speed of light)
through a vacuum. Their wavelengths vary from 10-15 m up to 104 m. The
different types of electromagnetic waves form a continuous spectrum.
Energy
Frequency
Wavelength
Radiation
Uses
Lowest
Lowest
Longest
Radio waves
TV signals
Microwaves
Cooking
Mobile
phone
signals
Optical
fibres
Seeing






increasing
increasing
decreasing



Visible light
(red to blue)
Ultraviolet



X-rays
Highest
Highest
Shortest
Infrared
Gamma
radiation
The Doppler effect
If a wave source is moving relative to an observer there will be
Detecting
forged bank
notes
Medical
images of
bones
Killing
cancer cells
High volume
High amplitude
Reflection
The normal is perpendicular (90) to the mirror.
Angles must be measured between the normal
and the light ray.
Images in mirrors are virtual.
Angle of incidence = Angle of reflection
Refraction
Waves undergo a change of direction when
refracted at an interface.
Diffraction
Waves spread out (diffract) when they pass
through a small gap. This only happens when
the size of the gap/obstacle is similar to the
wavelength.
- Microwaves
Moving away from observer
Moving towards observer
Wavelength increases
Wavelength decreases
Frequency decreases
Sounds become lower
pitched
Light moves to the red end
of the spectrum (redshift)
Frequency increases
Sounds become higher
pitched
Light moves to the blue end
of the spectrum
Observing red-shift
The wavelength of light observed from distant galaxies is
increased (red-shift). This tells us that all these galaxies are
moving away from us. We also observe that the further away
galaxies are, the faster they are moving away.
This suggests that the universe is expanding and began from a
very small initial point – so is evidence for the Big Bang
theory.
The Big Bang and the CMBR
The early (much smaller) universe would have had a lot of
energy. This energy would have produced radiation. As the
universe expanded this radiation also expanded (its wavelength
increased). We now observe it as microwaves filling the
universe, this is called the cosmic microwave background
radiation (CMBR). The Big Bang theory is the only theory that
explains the CMBR.