Energy is transferred when a
substance changes temperature,
the ammount depends on mass,
temp, change in SHC
E transfered = mass x SHC x temp chance
Energy is
tranfered hot
to cold
Temp is a measure
of hotness on an
arbitary scale
Energy is transfered when a substance changes state.
The amount depends on the mass, and SLH
Energy Transfer
Energy in the home can be acheived by:
curtains
Double glasing
cavity wall
insulation
Reflecting
foil
loft
insulation
careful design
draught
strip
energy transformations can be
represented by sankey diagrams
Trapped air reduces energy loss by convection
Convection currents are caused by
density changes
Shiny surfaces reflect infared radiation to reduce energy transfer
Conduction is transfer of KE
Air is a good
insulator and
reduces energy
transfer by
conduction
The Stable Earth
Earthquake waves travel through the earth, this
helps us understand the inside of the earth
Exposure to ultraviolet radiation causes sun burn and skin
cancer. Suncream/block reduces damage by ultraviolet
radiation, CFC's are causing the ozone layer to thin
Waves Transfer
Energy
Warm and hot
objects emit
infrared
radiation. It's
used for cooking
Microwaves can be used for cooking and comunication
when transmitter and reciever are in line of sight
Laser light is single colour and in phase
Laser light, visible light an infrared
are used to send signals along
optical fibres by total internal
reflection
All waves
have
amplitude,
frequency
and
wavelength
energy transfered = F x Wavelength
Digital and anolouge signals are used fo rcomunication. Morse code is
digital. Digital signals alow many to be transmitted at the same time.
Radio Waves, microwaves,
infrared, visible light and
ultraviolet are some of the waves
in the electromagnetic spectrum.
The energy of the wave increases
as wavelencth decreases. All
electromagnetic waves can be
reflected, refracted and diffracted
Radio waves
can be used for
communication.
Longer waves
diffract around
sounds
P2
Energy From The Sun
Kinetic energy from moving air turns blades on wind
turbines producing electrisity
Some gases in the
Earths atmosphere trap
heat from the Sin
increacing global
warming. Scientists
disagree about how
humans have effected
global warming in
increacing greenhouse
gases
Passive solar heating uses
glass to keep buildings warm
Photocells do not need fuel or cables, need little
maintenance and cause no pollution
Electricity Generation
Nuclear fuels are radioactive, cause cancer,
and waste remains radioactive for a long time
In power
stations,
fuels release
energy as
heat. Water
is heated to
produce
steam.
Steam turns
turbines.
Turbines turn
generators.
Enerators
produce
electricity
The main forms of ionising
radiation are alpha, beta, gamma.
Transformers change the size of the Voltage and current. The national grid transmits electricity aroundthe country at high voltage qand low current