Zusammenfassung der Ressource
waves and energy
- Waves and energy
- Radiowaves
- Used for
TV, phone,
radio
signals
- Lower
frequencies
than
microwaves
- Longer
wavelength
than
microwaves
- Frequencies range:
300,000Hz to 3000
million Hz
- Long
wavelengths
can diffract
around hills,
into tunnels
- The shorter
the
wavelength;
the more
info the
carry, the
shorter their
range and
the less they
spread out
- Microwaves
- Longitudinal
- Lower
frequencies
than visible
light
- Longer
wavelengths
than visible
light
- Diffract less
than
radiowaves
- Called
'Micro'waves as
shorter wavelength
than radiowaves
- Between
infrared and
radio in
electromagnetic
spectrum
- Used for
communications
and to transmit
signals
- X-radiation
- Used to
take photos
of bones-
check for
fractures
- Absorbed
more by
teeth and
bone than
soft tissue
- Lower
frequency
than
Gamma
- Ionises
subastances
it passes
through
- High
doses
kill
cells
- Low doses
cause
cancer
growth
- Organ consisting
soft tissue-filled
with contrast
medium- absorbs
X-ray easily
- Gamma rays
- Used to sterilize
surgical
equipment, kill
bacteria, kill
cancer cells
- High
frequency
- Cannot
be
seen/felt
- Mostly passes
through
skin/soft tissue
but some
absorbed by
cells
- Infrared
- Light shiny surfaces reflect
radiation falling on them
- Hotter
object
emit
more
- Dark,
matt
surfaces
absorb it
- All
objects
emit it
- Absorbed by
skin,
damages/kills
cells as heats
them up
- Infrared devices:Optical fibres,
Remote control headsets,
infrared scanners, heaters
- Types of Heat transfer
- Cavity
wall
insulation
- Loft
insulation
- Draught
proofing
- Convection
- Conduction
- Convection
- Radiation
- Biofuel
- Made from plants and waste
- Advantages
- Reliable
- Creates
jobs
- Quick
to
obtain
- Carbon
neutral
- Renewable
- Disadvantages
- Cost of fuel
- Loss of
food crops
- Deforestation-burning
increases CO2
- Generate
electricity
same way
as fossil
fuels
- Renewable energy sources
- Wind power
- Solar power
- Hydroelectric
- Wave
- Tidal
- Geothermal
- Biofuel
- Less effect
on on
environment
than fossil
fuels
- Non-renewable energy sources
- Fossil fuels
- Acid rain
- Extraction damages environment
- Affects habitats
- Release co2,
increases green
house effect
- Nuclear energy sources
- No greenhouse gases
- DIsposal of waste
- Consequence of accidents
- Types of stored energy
- Electrical
- Light
- Kinetic
- Electrical
- Chemical
- Gravitational and
elastic potenitals
- Redshift
- When objects move away
from us- waves are spread out
to longer wavelength
- Light from other
galaxies are redshifted
- The further away a
planet, the greater the
redshift
- Light from
distant galaxies-
see same pattern
but at lower
frequencies-
shifted towards
red end of
spectrum
- Energy transfer
- Methods
- Conduction
- Convection
- Radiation
- The bigger the
temperature difference
between an object and
its surrounding, the
faster the rate of
energy transferred by
heating
- Rate
transfer
depends
on;
surface
area,
surfaces,
material
and
volume
- Waves
- Transverse waves
perpendicular(90 degrees) to
direction of energy transfer
- Light and all other EMs waves, water
- Longitudinal waves
vibrations parallel to
direction of energy
transfer
- Compression and rarefaction
- Sound/ultrasound
- Doppler effect
- Change of frequency of wave when a
source moves towards an observer
- Longitudinal and transverse waves
- Frequency of source
moving towards you- seem
higher and wavelength
seem shorter
- Frequency of source moving towards
you- seem lower and wavelength seem
longer
- Waves and energy transfer
- Evaporation
- Gain kinetic energy
- Average
KE of
particles
left in
liquid is
lower, so
the liquid
is cooler
- increasing the rate depends
- Increasing temperature of gas
- Increasing surface area
- Decreasing density of gas
- High airflow
- Blueshift
- Shift in frequency of
photon towards higher
energy and shorter
wavelength
- National grid
- Supply and
demand is
increasing
- National grid is electricity
distribution network for uk
- Power can
be
generated
anywhere
on grid
- distribution- pylons or underground
- Pylons cheaper, ugly, easy to repair,
affected by weather,less reliable
- Need high
voltage/torrent
- Use transformers to
get high voltage for
grid-step up
transformer
- Use transformers to get
some voltage for home-step
down transformer
- Electricity and waves
- Non-renewable
- uranium
- pluntoium
- coal
- oil
- natural gas
- It will run out
- Damage environment
- Provide most energy
- Renewable
- Wind
- Wave
- Will never run out
- Doesn't damage environment
- Provide small amounts of energy
- Solar power
- Advantages
- No pollution
- Used in remote places
- No
environmental
damage
- Almost no running costs
- Disadvantages
- Solar cells expensive
- Only generate
small amounts of
electricity
- Unreliable
source of energy
unless sunny
country
- Wave power
- Advantages
- good in remote island areas
- renewable
- No pollution
- Minimal running costs
- disadvantages
- high start up costs
- visual impact
- unreliable
- NOT same as tidal
- Water drives turbine, turbine drives generator
- Convection
- Liquids and gases only
- All about changes in density
- Hotter particles with me kinetic energy
move from hotter to colder region-taking
their energy with them
- Specific heat capacity
- Tells you how much
energy materials can store
- Energy=mass x
specific heat capacity
x temperature
change
- Takes more heat energy to
increase temperature of some
materials compared to others.
These materials also release more
energy as they cool-act as heat
stores
- The amount of energy needed to raise
temperature of 1kg of the substance by 1
degree
- Energy effienciency
- Effectiveness-What gives you the
most money every year
- Cost effectiveness-What
has a shorter payback
time
- Payback time-How long it takes for money you
have saved on bills to equal the cost of putting
in insulation
- U-volume- shows how fast heat
is transferred through a material.
The better the insulator, the
lower the U-volume
- Efficiency of machines
- Efficiency = useful energy divided by total
energy/power in
- Energy not transferred
usefully from form to
another is dissipated- it
usually heats surroundings
and difficult to collect in or
use
- Have to consider
cost-effectiveness when choosing
appliances
- Low energy bulb- 4x as
efficient as ordinary bulb,
last longer but cost more
- LED bulbs-more efficient than
ordinary,last longer but cost more
and dont give out much light
- Wind power
- advantages
- no pollution
- no permanent
damage to
landscape
- minimal running cost
- renewable
- Disadvantages
- noisy
- high start costs
- need a lot of
them and a
lot of space
- unreliable
- turbine gets turned by wind,
turbine drives generator
- conduction in metal strips
- when heated at one
end, heat travels to
other end
- as heated-particles
vibrate-these vibrations
make the adjacent particles
vibrate. vibration and heat
passed along metal
- conduction in solids
- metals good conductors and
have free electrons (free to
move) in the metal
- poor conductors
have larger spaces
between particles or
are insulators
- vibrating particles- pass on
their extra kinetic energy to
their neighbours by colliding
with them-this is faster in
dense solids
- steady state theory
- big problems with this theory
- universe existed as it is now and it always will do
- based on idea the universe looks the same pretty much everywhere
- explains expansion
by suggesting
matter being
created in spaces as
universe expnds
- big bang theory
- estimated to have happened 14 billion years ago
- Thinks all matter and energy was
compressed then exploded
- can use current
rate of
expansion to
estimate age
- doesnt explain condtions or what caused the explosion
- hydroelectric
- advantages
- renewable
- peak demand
- reliable if no draught
- no pollution
- cheap to run
- disadvantages
- high start up cost
- people can lose homes
- destroys habitats
- rotting vegetation release methane and co2
- pumped storage-pump water back up
- tidal power
- advantages
- renewable
- good for storing energy for peak demand
- quite reliable
- minimal running costs
- disadvantages
- high start up costs
- energy will vary-height
of tide will vary
- sun and moon's gravity moves
water, drives turbine, turbine
drives generator
- the source of
energy=gravitational
force of moon and sun
- comparing energy sources
- renewable-have
lowest running
fuel costs
- renewable
often weather
dependent
- non-renewable
more reliable
- renewables need bigger
power stations-costs more
- geothermal energy
- advantages
- reliable
- minimal running costs
- renewable
- disadvantages
- high start up costs
- limited number of
possible locations
- can only happen where
earth's crust is thin
- dam
- built across a
valley, causing it
to flood
- water falls through dam,
gravitational energy of this water
converts to kinetic
- kinetic of water is used to turn a turbine and generate electricity
- sankey diagrams
- thickness of line represents
amount of energy
- can be drawn to scale so width
of each arrow is proportional
the amount of energy