1.1 Non Renewable Energy Sources: 1)
Coal 2) Oil 3) Natural gas 4) Nuclear
fuels (uranium/plutonium) ...a) They
will all run out b) They all damage the
environment c) They provide most of
1.1.1 Fossil Fuels: In a fossil fuel power station the
fuel is burnt and the heat produced turns water
into steam. The pressured steam turns a
turbine. +It is a quick process. +It is cheap. +It
is easy to get. -It is non-renewable. -It gives off
1.1.2 Nuclear Fission: In a nuclear reactor atoms of uranium or
plutonium undergo nuclear fission. This creates a huge
amount of energy as heat, heat turns into steam.+Huge
amounts of energy. +No carbon dioxide. +The fuel wont
run out for hundreds of years. -Creates lots of waste. -Can
cost a lot. -Takes a long time to generate the energy.
-Risk-could release radio-active waste.
1.2 Renewable Energy Sources: 1) Wind
2) Waves 3) Tides 4) Hydroelectric 5)
Solar 6) Geothermal 7) Food 8)
Biofuels...a) These will never run out.
b) they damage the environment in a
less nasty way than non-renewable.
c) They don't provide much energy
and some are unreliable.
1.2.1 Geothermal Power: In some parts of the
World (Iceland) that are close to Volcanic
areas, steam rises to the Earths surface
and can be piped directly to a power
station. +Does not have any fuel costs.
+Releases no Carbon Dioxide. -Can only
have them in a few areas.
1.2.2 Biomass/Biofuels: All forms of biomass involve
material produced by living organisms. This is
then burnt and steam is created. +Costs very
low. +Can also supply hot water. +Carbon
neutral. +Renewable. -Release atmospheric
pollutants. -Could contribute a great deal to
global warming. -Quite expensive-producing
biomass and converting to alcohols.
1.2.3 Solar: Solar cells generate a direct current when
light energy is absorbed by them. They transfer
light energy into electrical energy and produce a
direct current. +Inexhaustable fuel source. +No
pollution. +Often an excellent supplement to
other renewable sources. +Can be used for
powering other items: solar cars/satellites. -Low
energy production-would have to have lots of
them to produce a decent amount (more money).
-Only areas with lots of sunlight would be
1.2.4 Wind: Winds are convection currents set up in the Earths
atmosphere by energy from the sun. The kinetic energy of
wind drives wind turbines directly. +Inexhaustable fuel
source. +No pollution. +Often excellent supplement to other
renewable sources. -Low energy production (would have to
have lots-more money). -Noisy -Only suitable for windy
areas. -Can be expensive to maintain.
1.2.5 Tidal/Wave: As the waves move up and down, water
is allowed to flow through turbines in the barrage to
generate electricity. +Can reduce carbon emission. +It
is renewable. +As waves are so powerful, tidal
turbines can be small but still produce a lot of energy.
+Not too expensive. -The tides in an area have to
meet the required size to make enough energy.
-Destruction of sea life. -Can be unreliable as waves
aren't always big.
1.2.6 Hydroelectric: A hydroelectric power station turns kinetic energy
from water into electrical energy. A dam is built in a hilly area and
the water is collected into pipes down hill. +Inexhaustable fuel
source. +Minimal environmental impact. +Useful levels of energy
production. +Can be used throughout the World. -Smaller models
depend on availability of fast flooding streams. -Can have an impact
on river life.
1.3 Carbon neutral: When a plant is burnt and
another one is planted it causes a balance in
the Carbon dioxide levels. Carbon capture:
Where the carbon is captured and put
underground (where it came from) so it
doesn't get into the atmosphere.
2.1 The National Grid: Step up transformer- increase voltage,
decrease current. Step down transformer- decrease voltage to
make it safe.
2.1.1 The national grid is anything that involves
transporting power/electricity from power
stations to homes.
2.2 Advantages of putting electric cables
underground: +It is out of the way. +Not open to
storms. +Can't see it (not an eye-sore). +Not
dangerous for firemen/people.
2.3 Advantages of pilons: +Not open to
flooding/water damage. +Easier to maintain.
+Don't have to dig up areas around it.
3 Disadvantages of Energy
3.1 Non renewable disadvantages: 1) fossil fuels-green house gasses-global
warming. 2) Burning coal/oil-sulfur dioxide-acidic rain. 3) Coal mining-mess of the
landscape. 4) Oil spillages- serious environmental problems (effecting
mammals/birds). 5) Nuclear power-waste can be dangerous. 6) Nuclear fuel-
cheap but overall cost is high because of power plant and final decommissioning.
7) Nuclear power always carries the risk of major catastrophe.
3.2 Renewable disadvantages: Biofuels-lots of forest areas have to be
cleared so lots of species lose their habitat. The decay and burning
of this also increases carbon dioxide and methane emissions.
4 Wave Basics
4.1 Frequency is the number of complete waves passing
a certain point per second. Frequency is measured in
hertz (Hz). 1 Hz is 1 wave per second.
4.1.1 Wave speed = frequency x wavelength...
(m/s) = (Hz) x (m)...v = f x λ
4.2 Transverse waves: 1) Light and all other EM waves. 2) Ripples on water. 3)
Waves on strings. 4) A slinky spring wiggled up and down. IN TRANSVERSE
WAVES THE VIBRATIONS ARE PERPENDICULAR (AT 90o) TO THE
DIRECTION OF ENERGY TRANSFER OF THE WAVE.
4.3 Longitudinal waves: 1) Sound waves and ultrasounds. 2) Shock waves e.g. seismic waves. 3)
A slinky spring when you push the end. IN LONGITUDINAL WAVES THE VIBRATIONS ARE
PARALLEL TO THE DIRECTION OF ENERGY TRANSFER OF THE WAVE.
4.3.1 Sound waves
220.127.116.11 Sound waves are caused by vibrating objects. These
vibrations are passed through the surrounding medium
as a series of compressions. These will eventually
travels through someones inner ear and reach their
eardrum where they will hear the sound. The denser
the medium the faster the sound travels, sound
generally travels quicker in solids then liquids and
quicker in liquids then gases. Sound can't travel in
space because its mostly vacuum (no particles).
18.104.22.168.1 Sound waves will be reflected by hard flat surfaces,
this is why a large empty room sounds different to one
with things in. That's because these things absorb the
sound and stop it echoing. Echos are just reflected
sound waves. You hear a delay between the original
sound and the echo because the echoed sound waves
have to travel further so take longer to reach your ears.
Sound waves will also refract as they enter different
mediums-in denser materials they speed up.
22.214.171.124.1.1 High frequency sound waves sound high pitched. Low
frequency sound waves sound low pitched. Frequency is the
number of complete vibrations each second and is measured
in Hz. High frequency means shorter wavelength. The
loudness of a sound depends on the amplitude therefore the
bigger the amplitude the louder the sound.
5 Wave Properties
5.1 All waves can be reflected, refracted and diffracted, this
happens when waves arrive at an obstacle (or meet a
new material) and their direction of travel can be
126.96.36.199 Refraction is when waves go through a new material and change direction. Waves
will only be refracted if they meet a new medium at an angle. If they're travelling
along the normal they will change speed but not direction.
188.8.131.52.1 If light travels through a medium and goes from
fast to slow the angle of refraction gets smaller.
But if the light goes from slow to fast the angle of
refraction gets bigger.
184.108.40.206 When a wave spreads out after passing through a gap or past an object. The
amount of diffraction depends on the size of the gap relative to the wavelength of
the wave. The narrower the gap, or the longer the wavelength. the more the wave
spreads out. A narrow gap is one that is the same order of magnitude as the
wavelength of the wave (about the same size). So whether a gap counts as narrow
or not it depends on the wave in question. Light has a very small wavelength
(about 0.0005mm) so it can be diffracted but needs a really small gap.
220.127.116.11 Reflection of light is what allows us to see objects, light
bounces off them into our eyes. When light travelling in the
same direction reflects from an uneven surface such as a
piece of paper, the light reflects off at different angles.
When light travelling in the same direction reflects from an
even surface (smooth and shiny like a mirror) then its all
reflected at the same angle and you get a clear reflection.
ANGLE OF INCIDENCE = ANGLE OF REFLECTION.
18.104.22.168.1 1) The image is the same size as the object. 2) It is as far behind the
mirror as the object is in front. 3) The image is virtual and upright-it is
virtual because the object appears to be behind the mirror. 4) The image is
laterally inverted-the left and right sides are swapped.
6.1 EM waves with different wavelengths have different properties. We group them
into seven basic types but the regions merge together to form a continuous
spectrum. EM waves vary in wavelength however they all travel at the same
speed (3 x 10(8)m/s) in a vacuum. EM waves with higher frequencies have
shorter wavelengths. Because they have different different properties they are
used for different purposes.
6.1.1 EM SPECTRUM
6.1.2 Radio waves are EM radiation with wavelengths longer than about 10cm.
Long-wave radio (1-10Km) can be transmitted and received from half way
around the World, that's because long wavelengths diffract around the
curved surface of the Earth. They can also diffract around hills and into
tunnels. This diffraction effect makes it possible for radio signals to be
received even if the receiver isn't in line of the sight of th transmitter. The
radio waves used for TV and FM radio transmissions have very short
wavelengths (10cm-10m). To get reception you must be in direct sight of
the transmitter (doesn't bend round hills etc.). Short-wave radio
(10m-100m) can be received long distance because they are reflected
from the ionosphere (electrically charged layer in the Earth's upper
atmosphere). Medium wave signals can also reflect from the ionosphere
(depending on atmospheric conditions and time of day.
6.1.3 Microwaves are used for satellite communication and mobile
phones. The microwaves used for this need to be able to pass
through the Earth's watery atmosphere (radio waves can't).
For satellite TV, the signal from a transmitter is transmitted into
space where it is picked up by the satellites receiver dish
orbiting the Earth. The satellite transmits the signal back to
Earth in a different direction where it is received by a satellite
dish on the ground. Mobile phone calls also travel as
microwaves between your phone and the nearest transmitter.
Also microwaves are used by remote-sensing satellites-to
'see' through the clouds and monitor oil spills, track the
movement of icebergs and see how much rain forest has
been chopped down.
6.1.4 Infrared Waves are used for remote controls and optical fibres. Infrared
waves are used in lots of wireless remote controls, remote controls work
by emitting different patterns of infrared waves to send different
commands. Optical fibres can carry data over long distances very quickly.
They use infrared waves and visible light. The signal is carried as pulses
of light or infrared radiation and is reflected off the sides of a very narrow
core from one end of the fire to another.
6.1.5 Visible lens is useful for photography. Cameras use a lens to
focus visible light onto a light sensitive film or electronic structure.
The lens aperture controls how much light enters the camera, the
shutter speed determines how long the film or sensor is exposed
to the light. These make it possible to capture as much light as
you want in a photograph.
7 Origin of the Universe
7.1 Light from other galaxies is red sifted. Different chemical
elements absorb different frequencies of light. Each
element produces a specific pattern of dark lines at the
frequencies that it absorbs in the visible spectrum. When
we look at light from distant galaxies we can see the
same patterns but at slightly lower frequencies than they
should be-they're shifted towards the red end of the
spectrum-red shift. Measurements of the red-shift suggest
that all the galaxies are moving away from us very
quickly. More distant galaxies have greater red-shifts than
nearer ones. This means more distant galaxies are
moving away quicker than nearer ones. This provides
evidence the whole universe is expanding.
7.1.1 The Doppler Effect: When something emits waves
moving towards you or away from you the wavelengths
and frequencies of the waves seem different-compared
to when its stationery. Moving towards you: Higher
frequency, Shorter wavelength. Moving away from you:
Lower frequency, Longer wavelength.
22.214.171.124 The BIG BANG: According to this theory, all matter and energy n the universe must have
been compressed into a very small space. Then it exploded from that single 'point' and
started expanding. The expansion is still going on and we can use this expansion to
estimate its age (14 Billion years old). The STEADY STATE theory says that the universe
has always been existed as it is now and always will do. Its based on the fact that the
universe seems the same pretty much everywhere. The theory explains the apparent
expansion by suggesting that matter is being created in the spaces as the universe
expands. the discovery of CMBR was strong evidence that the Big Bang theory was the
more likely explanation of the 2.
126.96.36.199.1 The big bang theory also has its limitations. for example for
complicated reasons the Big Bang theory predicts the universe's
expansion should be slowing down however its actually speeding up.
It also doesn't explain what actually caused the explosion or what
conditions were like before the explosion (if there was one). It
seems that the Big Bang theory will be adapted to alter its
weaknesses rather than completely forgot about as it explains so
188.8.131.52.1.1 CMBR is cosmic microwave background
radiation. Scientists detected low frequency
electromagnetic radiation coming from all parts
of the universe (CMBR). Just after the Big Bang
while the universe was still extremely hot,
everything in the universe emitted high
frequency radiation. As the universe expanded it
has cooled, and this radiation has dropped in
frequency and is now seen as microwave