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P2A - Collecting Energy From the Sun

THE SUN

  • ULTIMATE SOURCE OF MOST OF OUR ENERGY - MOSTLY IN FORM OF HEAT AND LIGHT - SOME STORED ON EARTH AS FOSSIL FUELS - WIND ENERGY CAN BE TRACED BACK TO SUN (SUN HEATS AIR, HOT AIR RISES, COLD AIR TAKES ITS PLACE)
  • SUNS ENERGY CAN BE USED DIRECTLY - PHOTO CELLS AND SOLAR HEATING

CURVED MIRRORS

  • CONCENTRATE ENERGY FROM SUN - FOCUS SUNS LIGHT AND HEAT
  • SINGLE CURVED MIRROR - CAN BE USED AS A SOLAR OVEN
  • LARGE CURVED MIRRORS OR COMBINATION OF LOTS OF SMALLER ONES - USED TO GENERATE STEAM TO PRODUCE ELECTRICITY
  • ALL DEVICES THAT COLLECT ENERGY FROM SUN MOST EFFICIENT IF THEY TRACK SUNS MOVEMENT ACROSS SKY - COLLECTORS POINTED DIRECTLY AT SUN - CAN CAPTURE MAXIMUM AMOUNT OF HEAT AND LIGHT 
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P2A - Collecting Energy From the Sun

PHOTOCELLS

  • GENERATE DIRECT CURRENT (FLOWS THE SAME WAY AROUND THE CIRCUIT ALL THE TIME)
  • MADE OF SILICON, A SEMICONDUCTOR - WHEN SUNLIGHT FALLS ON CELL THE SILICON ATOMS ABSORB SOME OF THE ENERGY, KNOCKING LOSE SOME ELECTRONS - ELECTRONS FLOW AROUND CIRCUIT - ELECTRICITY
  • CURRENT AND POWER OUTPUT DEPENDS ON:
    • SURFACE AREA (BIGGER = MORE ELECTRICITY)    
    • INTENSITY OF LIGHT (BRIGHTER = MORE ELECTRICITY)
    • DISTANCE FROM LIGHT SOURCE - CLOSER TO CELL = MORE ELECTRICITY)
  • ADVANTAGES  - NO MOVING PARTS - STURDY. LOW MAINTENANCE, LAST A LONG TIME
  • DISADVANTAGES - NO SUNLIGHT, NO POWER - DON'T WORK AT NIGHT OR WHEN WEATHER'S BAD
    • DON'T NEED POWER CABLES OR FUEL
    • RENEWABLE ENERGY SOURCE - WON'T RUN OUT
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P2A - Collecting Energy From the Sun

PASSIVE SOLAR HEATING - ENERGY FROM SUN USED TO HEAT SOMETHING DIRECTLY

  • CAN REDUCE ENERGY NEEDED TO HEAT A BUILDING 
  • GLASS LETS IN HEAT AND LIGHT FROM SUN - ABSORBED BY THINGS, HEATING THEM UP
  • LIGHT FROM SUN - SHORT WAVELENGTH - CAN PASS THROUGH GLASS INTO ROOM
  • HEATED THINGS IN ROOM EMIT INFARED RADIATION - OF A LONGER WAVELENGTH - CAN'T ESCAPE THROUGH WINDOWS BUT IS REFLECTED BACK
  • WORKS TO HEAT THINGS UP AND KEEP HEAT INSIDE BUILDING

SOLAR WATER HEATERS

  • USE PASSIVE SOLAR HEATING - GLASS LETS HEAT AND LIGHT FROM SUN IN - ABSORBED BY BLACK PIPES AND HEAS UP WATER
  • CAN BE USED FOR WASHING OR PUMPED TO RADIATORS TO KEEP BUILDING WARM
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P2A - Collecting Energy From the Sun

WIND TURBINES - CONVERTS KINETIC ENERGY FROM WIND TURNING BLADES ON TURBINE INTO ELECTRICITY

  • WIND TURBINES PUT IN EXPOSED PLACES E.G. THE COAST, OUT AT SEA - SUN HEATS ATMOSPHERE, CAUSING CONVECTION CURRENTS - PRODUCES WIND

ADVANTAGES

  • CHEAP TO RUN - TOUGH, RELIABLE, WIND IS FREE
  • DOESN'T PRODUCE ANY POLLUTING WASTE
  • RENEWABLE ENERGY RECOURCE - WON'T RUN OUT

DISADVANTAGES

  • NEED 1500 WIND TURBINES TO REPLACE ONE COAL POWERED POWER STATION - CREATE VISUAL AND NOISE POLLUTION
  • NO WIND, NO POWER - IMPOSSIBLE TO INCREASE SUPPLY WHEN THERE'S HIGH DEMAND
  • DIFFICULT TO FIND SUITABLE PLACES TO BUILD TURBINES - NEED TO BE SPACED OUT AND IN WINDY PLACES
  • EXPENSIVE TO SET UP A WIND FARM
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P2B - Generating Electricity

THE NATIONAL GRID

NETWORK OF PYLONS AND CABLES THAT COVERS THE WHOLE COUNTRIES - TAKES ELECTRICITY FROM POWER STATIONS TO WHERE ITS NEEDED IN HOMES AND INDUSTRY - ENABLES POWER TO BE GENERATED ANYWHERE ON GRID AND SUPPLIED ANYWHERE ELSE ON GRID

POWER STATIONS

(http://www.bbc.co.uk/schools/gcsebitesize/science/images/21c_national_grid.gif)

  • 1 - BOILER USES FUEL TO PRODUCE HEAT WHICH GENERATES STEAM
  • 2 - MOVING STEAM DRIVES BLADES OF TURBINE
  • 3 - ROTATING MOVEMENT OF TURBINE CONVERTED INTO ELECTRICITY BY GENERATOR USING ELECTROMAGNETIC INDUCTION AND THE POWER THEN GOES TO THE NATIONAL GRID
  • POWER STATIONS ARE INEFFICIENT - OVER HALF ENERGY PRODUCED WASTED AS HEAT AND NOISE
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P2B - Generating Electricity

DIFFERENT POWER SOURCES

  • FOSSIL FUELS - READILY AVAILABLE, CONCERNTRATED SOURCE OF ENERGY BUT CAUSE ACID RAIN AND MAKE CARBON DIOXIDE. HAVE TO BUY THEM FROM OTHER COUNTRIES AND WILL RUN OUT
  • BIOMAS - STUFF FROM PLANTS OR ANIMALS THAT CAN BE FERMENTED TO PRODUCE METHANE - RENEWABLE AND WE CAN QUICKLY MAKE MORE, CARBON NEUTRAL - NOT THAT CONCENTRATED
  • NUCLEAR POWER - USING HEAT RELEASED BY URANIUM - DISPOSAL OF WASTE DANGEROUS - CONCERNTRATED SOURCE OF ENERGY, READILY AVAILABLE - NON RENEWABLE
  • PHOTOCELLS - ABSORB ENERGY FROM SUN CONVERTED INTO ELECTRICITY - RENEWABLE AND ENVIRONMENTALLY FRIENDLY - NO SUNLIGHT, NO POWER
  • WIND POWER - RENEWABLE, ENVIRONMENTALLY FRIENDLY, NO WIND, NO POWER - VISUAL POLLUTION AND SOUND POLLUTION - WIND FARMS EXPENSIVE TO SET UP
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P2B - Generating Electricity

ELECTROMAGNETIC INDUCTION - CREATION OF VOLTAGE (AND MAYBE CURRENT) IN A WIRE WHICH IS EXPERIENCING A CHANGE IN MAGNETIC FIELD

THE DYNAMO EFFECT - USING ELECTROMAGNETIC INDUCTION TO TRANSFORM KINETIC ENERGY INTO ELECTRICAL ENERGY

  • TWO DIFFERENT SITUATIONS OF EM INDUCTIONPRODUCES ALTERNATING CURRENT - DIRECTION OF MOVEMENT REVERSED THEN VOLTAGE REVERSED TOO
    • AN ELECTRICAL CONDUCTOR (COIL OF WORE) MOVES THROUGH A MAGNETIC FEILD
    • A MAGNETIC FIELD THROUGH AN ELECTRICAL CONDUCTOR CHANGES (GETS BIGGER, SMALLER OR REVERSES)
  • TO GET A BIGGER VOLTAGE OR CURRENT, YOU CAN INCREASE
    • THE STRENGTH OF THE MAGNET
    • THE NUMBER OF TURNS ON THE COIL
    • THE SPEED OF MOVEMENT

 EFFICIENCY = (USEFUL ENERGY OUTPUT / TOTAL ENERGY INPUT) X 100

  • POWER STATIONS PRODUCE A LOT OF WASTE ENERGY - E.G. HEAT LOST TO ENVIRONMENT
  • TOTAL ENERGY = USEFUL ENERGY (ELECTRICITY) + WASTED ENERGY
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P2B - Generating Electricity

GENERATORS - ROTATE IN A COIL OF A MAGNETIC FIELD

  • (http://www.trade-equip.co.uk/blog/wp-content/uploads/2011/07/graph1a.jpg)EVERY HALF TURN THE CURRENT IN THE COIL SWAPS DIRECTION - (WHEN ROTATING, ANY ONE PART OF THE COIL IS HEADING TOWARDS THE MAGNETS SOUTH POLE FOR ONLY HALF A TURN AND THEN IT HEADS BACK UP TOWARDS NORTH POLE)
  • MEANS THAT GENERATORS PRODUCE ALTERNATING CURRENT            --------->
  • TURN COIL FASTER - PRODUCES MORE PEAKS AND A HIGHER VOLTAGE AND CURRENT - CURVE ON GRAPH WOULD BE CLOSER TOGETHER (MORE CYCLES PER SECOND) AND TALLER (REACHING HIGHER VOLTAGE)
  • FREQUENCY OF AC CURRENT MEASURED IN HZ 
  • IN UK, ELECTRICITY HAS 50HZ (COIL IN GENERATOR AT POWER STATION ROTATING 50 TIMES PER SECOND)

BATTERIES - DC ELECTRICITY

  • DIRECT CURRENT
  • CURRENT PLOTTED ON GRAPH WOULD BE A STRAIGHT LINE

DYNAMOS ON BIKES - WORK SLIGHTLY DIFFERENTLY - ROTATE MAGNET NEAR A COIL - EXACTLY THE SAME CONCEPT - STILL USING EM INDUCTION

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P2C - Global Warming

THE EARTHS ATMOSPHERE

  • EARTH SURROUNDED BY ATMOSPHERE MADE UP OF VARIOUS GASSES - THE AIR
  • GASES IN ATMOSSPHERE FILTER OUT CERTAIN TYPES OF RADIATION FROM SUN BY ABSORBING AND REFLECTING RADIATION OF CERTAIN WAVELENGTHS (INFARED)
  • WAVELENGTHS OF SOME RADIATION (MAINLY VISIBLE AND RADIO) PASS THORUGH ATMOSPHERE

THE GREENHOUSE EFFECT

  • EARTH ABSORBS SHORT WAVELENGTH EM RADIATION FROM SUN - WARMS EARTHS SURFACE
  • EARTH THEN EMITS SOME OF THIS RADIATION AT A LONGER WAVE LENGTH (INFARED) BACK INTO SPACE - COOLS DOWN
  • A LOT OF INFARED RADIATION ABSORBED BY ATMOSPHERIC GASES E.G. CO2, METHANE, WATER VAPOUR
  • GASES THEN RE-RADIATE HEAT IN ALL DIRECTIONS INCLUDING BACK TOWARDS EARTH
  • ATMOSPHERE ACTS AS INSULATING LAYER - STOPS EARTH LOSING HEAT AT NIGHT
  • WITHOUT GREENHOUSE GASES (CO2, METHANE, WATER VAPOUR), EARTH WOULD BE A LOT COLDER
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P2C - Global Warming

INCREASING GREENHOUSE GASES

  • CARBON DIOXIDE - AVAILABILITY OF ENERGY - USING MORE ENERGY (E.G. DRIVING CARS) THAT WE GET FROM BURNING FOSSIL FUELS - BURNING FOSSIL FUELS RELEASES CO2
  • INCREASED POPULATION - MORE LAND NEEDED FOR HOUSES AND FOOD - SPACE OFTEN MADE BY CHOPPING DOWN TREES AND BURNING THEM - FEWER TREES MEANS LESS CO2 IS ABSORBED AND BURNING RELEASES MORE 
  • CO2 COMES FROM NATURAL SOURCES E.G. RESPIRATION OF ANIMALS AND PLANTS, VOLCANIC ERUPTIONS
  • METHANE - GROWING POPULATION - CATTLE FARMING INCREASED TO FEED IT - CATTLE DIGESTION PRODUCES METHANE
  • LANDFILL SITES - DECAYING WASTE PRODUCES METHANE - AMOUNT OF WASTE GROWING
  • MATHANE COMES FROM NATURAL SOURCES E.G. VOLCANOES, WETLANDS, WILD ANIMALS
  • WATER VAPOUR - NATURAL SOURCES - OCEANS, SEAS RIVERS, LAKES - WATER VAPOUR COULD INCREASE AS GLOBAL TEMPERATURE INCREASES
  • POWER STATIONS - PRODUCE WATER VAPOUR - EFFECTS AMOUNT IN LOCAL AREA

 

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P2C - Global Warming

CLIMATE CHANGE AND GLOBAL WARMING

  • AS GREENHOUSE GASES INCREASE (GREENHOUSE EFFECT), SO DOES THE TEMPERATURE OF THE EARTH
  • CLIMATE VARIES NATURALLY BUT SCIENTISTS SAY THAT NATURAL CHANGES DON'T EXPLAIN THE GRADUAL HEATING UP OF THE EARTH - THIS IS DUE TO HUMAN ACTIVITY CAUSING INCREASE OF GASES
  • NEW SCIENTIFIC CONSENSUS - HUMANS CAUSING GLOBAL WARMING

CAUSES 

  • CLIMATE VERY COMPLICATED - CONDITIONS IN ATMOSPHERE, OCEANS AND LAND EFFECT ONE ANOTHER E.G. GLOBAL WARMING AFFACTS WEATHER - LONGER DROUGHTS - WATER WARMS UP - CAUSES HURRICANES -
  • EFFECTS ABILITY TO GROW FOOD - TOO DRY OR TOO WET - WORSEN AS GLOBAL WARMING INCREASES
  • NATURAL CAUSES - ASH AND GAS THROWN INTO ATMOSPHERE BY VOLCANOES REFLECT SUN RAYS BACK INTO SPACE - EARTH COOLS - CHANGES IN ORBIT AROUND SUN CAUSE ICE CHANGES
  • HUMAN CAUSES - RISING CO2 CAUSES GREENHOUSE EFFECT - SOOT AND GASES PRODUCED BY FACTORIES REFLECT HEAT BACK TO EARTH - INCREASE IN LOCAL TEMPERATURE
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P2D - Fuels for Power

POWER (W) = VOLTAGE (V) X CURRENT (A)

  • 1 WATT MEANS 1 JOULE PER SECOND
  • THE HIGHER THE POWER RATING, THE MORE EXPENSIVE THE DEVICE WILL BE TO RUN

KILOWATT HOUR - AMOUNT OF ELECTRICAL ENERGY CONVERTED BY A 1KW APPLIANCE LEFT ON FOR 1 HOUR

  • HIGHER THE POWER RATING OF THE APPLIANCE, THE LONGER YOU LEAVE IT ON, THE MORE ENERGY IT CONSUMES AND THE MORE IT COSTS

ENERGY SUPPLIED (KWH) = POWER (KW) X TIME (H)

COST = NUMBER OF UNITS (KWH)  X PRICE PER UNIT

OFF PEAK ELECTRICITY - ENERGY SUPPLIED DURING THE NIGHT

  • ADVANTAGES - COST EFFECTIVE TO ELECTRICITY COMPANY - POWER STATIONS CAN'T BE TURNED OFF AT NIGHT - CHEAPER FOR CONSUMER IF THEY BUY ELECTRICITY DURING HOURS OF LOW DEMAND
  • DISADVANTAGES - SLIGHTLY INCREASED RISK OF FIRE - MORE APPLIANCES RUNNING AT NIGHT WITH NO ONE WATCHING - FITTING ROUTINE AROUND OFFPEAK HOURS LIMITS ENJOYMENT DURING DAY
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P2D - Fuels for Power

TRANSFORMERS

  • FOR POWER TO BE TANSMITTED, A HIGH VOLTAGE OR A HIGH CURRENT IS NEEDED - HIGH CURRENT CAUSES CABLES TO GET TOO HOT WHICH IS INEFFICIENT (ENERGY LOST AS HEAT)
  • CHEAPER TO INCREASE VOLTAGE - VOLTAGE TRANSFORMED TO 400 000 V BEFORE BEING SENT ROUND COUNTRY (KEEPS CURRENT VERY LOW) BY STEP UP TRANSFORMER 
  • HIGH VOLTAGE IS CHEAPEST WAY TO TRANSMIT ELECTRICITY (EVEN THOUGH PIG PYLONS WITH HUGE INSULATORS AND TRANSFORMER THEMSELVES ARE NEEDED)
  • VOLTAGE IS BROUGHT DOWN TO SAFE, USABLE LEVELS FOR HOMES BY LOCAL STEP DOWN TRANSFORMERS IN TOWNS
  • TRANSFORMERS ONLY WORK WITH AC - MAIN REASON MAINS ELECTRICITY IS AC
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P2E - Nuclear Radiation

IONISATION - ATOMS LOSING OR GAINING ELECTRONS CAUSING NUCLEUS TO BE UNSTABLE

  • RADIOACTIVE MATERIALS GIVE OUT NUCLEAR RADIATION IN FORMS OF ALPHA, BETA AND GAMMA OVER TIME - CAUSES IONISATION OF ATOMS
  • POSITIVE IONS FORMED WHEN ATOMS LOSE ELECTRONS, NEGATIVE IONS FORMED WHEN ATOMS GAIN THEM
  • IONISATION CAN INITIATE CHEMICAL REACTIONS BETWEEN DIFFERENT ATOMS
  • RADIATION ENTERS HUMAN CELLS - CAN IONISE MOLECULES AND DAMAGE DNA - CAUSE MUTATIONS
  • HIGH DOSES CAN KILL CELLS COMPLETELY
  • IONISING POWER OF EACH KIND OF RADIATION - LINKED TO HOW FAR IT CAN PENETRATE MATERIALS - FIRTHER THE RADIATION CAN PENETRATE BEFORE HITTING AN ATOM, THE LEAST IONISING IT IS

PENETRATING POWER - HELPS IDENTIFY TYPE OF RADIATION

  • (http://hyperphysics.phy-astr.gsu.edu/hbase/nuclear/imgnuc/radpen.gif)PLACE MATERIAL BETWEEN RADIATION SOURCE AND DETECTOR (GEIGER COUNTER)
  • ALPHA IS STOPPED BY A SHEET OF PAPER
  • BETA - STOPPED BY THIN SHEET OF ALUMINIUM 
  • GAMMA - STOPPED BY THINK SHEET OF LEAD
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P2E - Nuclear Radiation

ALPHA PARTICLES

  • RELATIVELY BIG, HEAVY AND SLOW MOVING - 2 PROTONS AND 2 NEUTRONS
  • STOPPED QUICKLY BECAUSE OF SIZE - DON'T PENETRATE PAPER OR SKIN
  • STRONGLY IONISING - COLLIDE WITH A LOT OF ATOMS AND KNOCK ELECTRONS OFF BEFORE SLOWING

BETA PARTICLES

  • ELECTRONS - SMALL AND QUITE FAST MOVING
  • PENETRATE MODERATELY BEFORE COLLIDING - MODERATELY IONISING
  • CAN BE STOPPED BY A FEW MILLIMETERS OF ALUMINIUM

GAMMA RAYS

  • TYPE OF EM RADIATION - VERY HIGH FREQUENCY - RELEASED WHEN OBJECT HAS EXTRA ENERGY TO GET RID OF AFTER EMITING ALPHA OR BETA PARTICLE
  • NO MASS AND NO CHARGE - PENETRATES A LONG WAY - WEAKLY IONISING - PASS THROUGH NOT COLLIDE
  • STOPPED BY VERY THICK CONCRETE OR A FEW CM OF LEAD
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P2E - Nuclear Radiation

USES OF RADIATION

  • ALPHA - SMOKE DETECTORS - WEAK SORCE OF ALPHA RADIATION CLOSE TO TWO ELECTRODES - RADIATION IONISES AIR AND CURRENT FLOWS BETWEEN ELECTRODES - SMOKE ABSORBS RADIATION SO IF THERES A FIRE, CURRENT STOPS AND ALARM SOUNDS
  • BETA - MEDICAL USES - TACERS - RADIOACTIVE SOURCE INJECTED OR SWALLOWED BY PATIENT - PROCESS AROUND BODY CAN BE TRACED USING EXTERNAL RADIATION DETECTOR - COMPUTER CONVERTS READING TO TV DISPLAY SHOWING WHERE STRONGEST READING IS COMING FROM - CAN SHOW WHETHER BODY IS WORKING PROPERLY
  • BETA USED BECAUSE IT PASSES OUT OF BODY AND THINGS ONLY RADIOACTIVE FOR A FEW HOURS
  • BETA - INDUSTRIAL USES - THICKNESS CONTROL - DIRECT RADIATION THROUGH PAPER BEING MADE AND PUT DETECTOR AT OTHER SIDE - AMOUNT DETECTED DECREASES - PAPER TOO THICK
  • RADIOACTIVE SUBSTANCE MUSTN'T DECAY QUICKLY FOR THIS USE - READING SLOWLY  FALL - TOO THICK 
  • BETA USED - READING EFFECTED BY THICKNESS - NOT TOO GREATER OR WEAKER PENETRATING POWER
  • GAMMA - MEDICAL USES - TREATING CANCER - KILLS ALL LIVING CELLS - DIRECTED CAREFULLY 
  • STERILISING MEDICAL EQUIPMENT - KILLS MICROBES - BETTER THAN BOILING - DAMAGES INSTRUMENTS
  • USED BECAUSE ITS A STRONGLY RADIOACTIVE SOURCE THAT LASTS A LONG TIME - NO REPLACING
  • GAMMA - INDUSTRIAL USES - TESTING AIROPLANE TURBINE BLADES FOR CRACKS
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P2E - Nuclear Radiation

NUCLEAR POWER

  • NUCLEAR POWER STATIONS USES NUCLEAR FISSION TO PRODUCE HEAT TO CREATE STEAM
  • IN NUCLEAR FISSION, URANIUM ATOMS ARE SPLIT IN TWO, RELEASING LOTS OF HEAT ENERGY
  • WATER USED AS COOLANT - TAKES AWAY HEAT PRODUCED BY FISSION PROCESS - HEAT USED TO PRODUCE STEAM TO DRIVE TURBINE AND GENERATOR

NUCLEAR WEAPONS

  • USED URANIUM FUEL FROM NUCLEAR POWER STATIONS REPROCESSED - WAY OF DEALING WITH RADIOACTIVE WASTE THAT WOULD OTHERWISE HAVE TO BE STORED
  • AFTER REPROCESSING, URANIUM AND PLATONIUM IS LEFT
  • REUSE URANIUM IN NUCLEAR POWER STATION
  • PLUTANIUM USED TO MAKE NUCLEAR BOMBS
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P2E - Nuclear Radiation

ADVANTAGES

  • CAN MAKE LOTS OF ENERGY WITHOUT RELEASING A LOT OF CO2
  • NUCLEAR REACTIONS RELEASE A LOT MORE ENERGY THAN CHEMICAL REACTIONS LIKE BURNING - TAKES A LOT LESS URANIUM TO PRODUCE SAME AMOUNT OF POWER AS FOSSIL FUEL
  • RELATIVELY CHEAP
  • STILL PLENTY OF URANIUM LEFT 

DISADVANTAGES

  • EXPENSIVE TO BUILD AND MAINTAIN
  • TAKES LONGER TO START UP NUCLEAR POWER STATIONS THAN FOSSIL FUEL POWER STATIONS
  • PROCESSING URANIUM BEFORE USE CAUSES POLLUTION
  • RISK OF LEAKS OF RADIOACTIVE MATERIALS OR MAJOR DISASTERS LIKE CHERNOBYL DISASTER
  • RADIOACTIVE WASTE - DANGEROUS AND DIFFICULT TO REPROCESS OR DISPOSE OF SAFELY
  • NUCLEAR POWER STATIONS HAVE TO BE DECOMISSIONED WHEN TO OLD FOR USE - EXPENSIVE
  • URANIUM - NON RENEWABLE RECOURCE 
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P2E - Nuclear Radiation

PROTECTION AGAINST RADIOACTIVE MATERIALS

  • RADIOACTIVE SOURCES NEED TO BE STORED SAFELY - KEPT IN LABELLED LEAD BOX AND LEFT OUT FOR AS SHORTER TIME AS POSSIBLE TO KEEP EXPOSURE TIME SHORT
  • RADIOACTIVE SOURCES NEED TO BE HANDLED WITH TONGS - NEVER ALLOW SKIN CONTACT - KEEP AT ARMS LENGTH AT ALL TIME - KEEP IT POINTING AWAY FROM YOU AND AVOID LOOKING DIRECTLY AT IT
  • INDUSTRIAL NUCLEAR WORKERS NEED TO WEAR FULL PROTECTIVE SUITS TO PREVENT TINY RADIOACTIVE PARTICLES BEING BREATHED IN OR LODGING THEMSELVES IN SKIN, FINGERNAILS ETC.
  • LEAD LINED SUITS, LEAD OR CONCRETE BARRIERS AND THICK LEAD SCREENS USED TO SHEILD WORKERS FROM GAMMA RAYS IN HIGHLY RADIOACTIVE AREAS
  • WORKERS USE REMOTE CONTROL ROBOT ARMS TO CARRY OUT TASKS IN HIGHLY RADIOACTIVE AREAS
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P2E - Nuclear Radiation

DISPOSAL OF RADIOACTIVE WASTE

  • LOW LEVEL WASTE - MOST WASTE FROM POWER STATIONS AND HOSPITALS - PAPER, GLOVES, CLOTHING ETC - DESPOSED OF BY BURYING IN SECURE LANDFILL SITES
  • HIGH LEVEL WASTE - STAYS RADIOACTIVE FOR TENS OF THOUSANDS OF YEARS - HAS TO BE TREATED VERY CAREFULLY - SEALED IN GLASS BLOCKS WHICH ARE SEALED IN METAL CANISTERS - BURRIED DEEP UNDERGROUND
  • DIFFICULT TO FIND SUITABLE PLACES TO BURY HIGH LEVEL WASTE - HAVE TO BE GEOLOCICALLY STABLE - SUDDEN MOVEMENTS IN ROCK COULD DISTURB CANISTERS - CAUSE THEM TO LEAK - IF GET INTO GROUND WATER, COULD INFECT DRINKING WATER
  • WHEN APPROPRIATE AREA FOUND, LOCALS OFTEN OBJECT - HIGH LEVEL WASTE MOSTLY KEPT ON SITE
  • NOT ALL WASTE HAS TO BE DESPOSED OF - SOME CAN BE REPROCESSED - RECLAIMED USEFUL
  • NUCLEAR POWER STATIONS AND REPROCESSING PLANTS SECURE - HAVE HIGH FENCES AND SECURITY CHECKS RUN ON PEOPLE GOING IN AND OUT - COULD BE TARGET FOR TERRORISTS - USE STOLEN RADIOACTIVE MATERIAL TO MAKE DIRTY BOMB OR ATTACK STATION DIRECTLY
  • STRICT REGULATIONS ON HOW WASTE DESPOSED OF - COULD CHANGE AS MORE INFORMATION ON RADIOACTIVE MATERIALS AND PROS AND CONS OF DISPOSAL METHODS IS DISCOVERED 
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P2F - Exploring Our Solar System

THE SOLAR SYSTEM

  • SOLAR SYSTEM - PLANETS, MOONS, ASTROIDS ETC. ORBITING THE SUN IN ELONGATED ELIPSES
  • INNER PLANETS - MERCURY, VENUS, EARTH, MARS - PLANETS CLOSEST TO SUN
  • ASTROID BELT - RING OF ASTROIDS ORBITING SUN - BETWEEN INNER AND OUTER PLANETS
  • OUTER PLANETS - JUPITER, SATURN, URANUS, NEPTUNE
  • STARS - HUGE, VERY HOT, FAR AWAY FROM EARTH - GIVE OUT A LOT OF LIGHT - VISIBLE TO NAKED EYE
  • PLANETS - SMALLER, NEARER - REFLECT LIGHT FALLING ON THEM - SOME VISIBLE TO NAKED EYE
  • MOONS - ORBIT MANY PLANETS - SOME HAVE MULTIPLE - EARTH HAS ONE

GRAVITATIONAL ATTRACTION

  • GRAVITATIONAL ATTRACTION - PULLS EVERYTHING IN UNIVERSE TOWARDS EVERYTHING ELSE 
  • FORCE OF GRAVITY HUGE BETWEEN STARS AND PLANETS (BIGGER OBJECT, BIGGER PULL) - MAKES PLANETS ORBIT SUN AND MOON ORBIT PLANETS
  • PULL OF OBJECT GETS SMALLER THE FURTHER AWAY THE OBJECT IS - EARTH ORBITS SUN ONLY
  • EARTH ALREADY MOVING - GRAVITY MAKES MOVING THINGS CHANGE COURSE - CIRCULAR ORBIT
  • CIRCULAR MOTION - CAUSED BY A FORCE (PULL) TOWARDS THE CENTRE OF THE CIRCLE - FOR PLANETS THIS IS GRAVITY - FORCE THAT CAUSES CIRCULAR MOTION CALLED CENTREPETAL FORCE
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P2F - Exploring Our Solar System

GALAXIES

  • SUN - ONE OF THE BILLIONS OF STARS IN MILKY WAY - ABOUT HALF WAY ALONG ONE OF THE SPIRAL ARMS OF MILKY WAY (GALAXY THAT EARTH IS IN)
  • DISTANCE BETWEEN NEIGHBORING STARS IN GLAXY - MILLIONS OF TIMES GREATER THAN DISTANCE BETWEEN PLANETS IN SOLAR SYSTEM
  • GRAVITY KEEPS STARS IN GALAXY TOGETHER 
  • GALAXIES ROTATE - LIKE CATHERINE WHEEL
  • MILLIONS OF TIMES FURTHER APART THAN STARS WITHIN A GALAXY
  • UNIVERSE HAS BILLIONS OF GALAXIES
  • UNIVERSE IS MAINLY EMPTY SPACE - REALLY BIG

LIGHT YEARS - DISTANCE THAT LIGHT TRAVELS THROUGH A VACUUM IN ONE YEAR

  • SCIENTISTS USE LIGHTYEARS WHEN TALKING ABOUT OBJECTS IN UNIVERSE E.G. DISTANCES BETWEEN GALAXIES - USING KM GIVES TOO BIGGER NUMBERS
  • 1 LIGHT YEAR EQUAL TO 9 460 000 000 000 KM
  • CLOEST STAR TO EARTH AFTER SUN IS 40 000 000 000 000 KM AWAY - ABOUT 4.2 LIGHTYEARS
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P2F - Exploring Our Solar System

BLACK HOLES - MADE WHEN LARGE STARS EXPLODE

  • REALLY BIG STAR USES UP MOST OF IT'S FUEL - SOMETIMES EXPLODES
  • CREATES VERY DENSE EXPLOSION - NOTHING CAN ESCAPE IT'S GRAVITATIONAL PULL
  • LARGE MASS, SMALL VOLUME AND VERY HIGH DENSITY - LIGHT CAN'T ESCAPE PULL - "BLACK"
  • NOT VISIBLE - ASTRONOMERS HAVE TO DETECT THEM IN OTHER WAYS E.G. OBSERVING X RAYS EMITTED BY HOT GASES FROM STARS AS THEY SPIRAL INTO BLACK HOLE

EXPLORING THE SOLAR SYSTEM - MANNED SPACECRAFT

  • SOLAR SYSTEM BIG - SENDING MANNED SPACECRAFT TO MARS TAKES YEARS - NEED TO CARRY A LOT OF FUEL - HEAVY AND EXPENSIVE
  • DIFFICULT FOR MEN TO KEEP ALIVE AND HEALTHY - WOULD NEED FOOD, WATER, OXYGEN
    • TEMP NEED TO BE REGULATED - KEEP TOXIC GASES OUT
    • SPACECRAFT HAVE TO SHEILD MEN FROM RADIATION IN SPACE
    • LONG PERIODS IN LOW GRAVITY - MUSCLE WASTAGE AND LOSS OF BONE TISSUE
    • PSYCOLOGICALLY STRESSFUL - YEARS IN SMALL SPACE WITH SAME PEOPLE
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P2F - Exploring Our Solar System

UNMANNED PROBES - SPACECRAFT CONTAINING INSTRUMENTS TO RECORD FOTTAGE TO SEND BACK 

  • FLY-BY MISSIONS SIMPLEST - PROBE PASSES CLOSE BY OBJECT BUT DOESN'T LAND - GATHER DATA ON TEMPERATURE, MAGNETIC AND GRAVITATIONAL FEILDS, RADIOACTIVITY LEVELS ETC.
  • SOME DESIGNED TO ENTER PLANETS ATMOSPHERE - BURN UP AFTER DATA COLLECTED AND SENT BACK
  • SOME DESIGNED TO LAND ON OTHER PLANETS - CARRY EXPLORATION ROVERS - WANDER ABOUT
  • ADVANTAGES:
    • DON'T HAVE TO CARRY FOOD, WATER, OXYGEN AND WITHSTAND CONDITIONS LETHAL TO HUMANS
    • NO HUMANS WEIGHING PROBE DOWN - MORE INSTRUMENTS CAN BE FITTED
    • CHEAPER - CARRY LESS, DON'T HAVE TO COME BACK TO EARTH
    • NO ONE GETS HURT IN UNEXPECTED CRASHES/BURNING
  • DISADVANTAGES:
    • CAN'T THINK FOR THEMSELVES - CAN'T OVERCOME SIMPLE POTENTIALLY DISASTEROUS PROBLEMS THAT HUMAN BRAINS HAVE TO CAPACITY TO
    • CAN'T DO MAINTAINANCE AND REPAIRS LIKE PEOPLE
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P2G - Threats to Earth

THE MOON - SCIENTISTS THINK IT WAS FORMED FROM ANOTHER PLANET COLLIDING WITH EARTH

  • SOON AFTER EARTH FORMED - SMALLER MARS SIZED PLANET CRASHED INTO IT
  • IN HEAT OF COLLISION, DENSE IRON CORES OF TWO PLANETS MERGED TO FORM EARTHS CORE
  • LESS DENSE MATERIAL EJECTED AS HOT DUST AND ROCKS - ORBITTED AROUND EARTH - EVENTUALLY CAME TOGETHER TO FORM MOON
  • EVIDENCE:
    • MOON - LOWER DENSITY THAN EARTH - NO IRON CORE
    • MOON ROCKS CONTAIN FEW SUBSTANCES WHICH EVAPORATE AT LOW TEMPERATURES - MOON FORMED FROM HOT MATERIAL

ASTEROID BELT - BELT OF ASTEROIDS ORBITING BETWEEN MARS AND JUPITER

  • ROCKS BETWEEN MARS AND JUPITER DIDN'T FORM PLANET BECAUSE OF JUPITERS STRONG GRAVITATIONAL ATTRACTION
  • MILLIONS OF ASTEROIDS (PILES OF RUBBLE AND ROCK) ORBIT SUN BETWEEN ORBITS OF JUPITER AND MARS
  • USUALLY STAY IN ORBITS - SOMETIMES COLLIDE - PUSHED AND PULLED INTO DIFFERENT ONES
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P2G - Threats to Earth

METEORITES - ROCKS WHICH HAVE CRASHED DOWN TO EARTH

  • METEORS - ROCKS OR DUST THAT ENTERS EARTHS ATMOSPHERE - BURN UP AS PASS THROUGH ATMOSPHERE - SHOOTING STARS
  • SOMETIMES PART CRASHES TO EARTHS SURFACE AS METEORITE - RARE - CAN CAUSE HAVOC
  • START FIRES, THROW HOT DUST AND ROCKS INTO AIR, MAKE CRATERS
  • DUST AND SMOKE CAN BLOCK OUT SUN FOR MONTHS - CLIMATE CHANGE - SPECIES EXTINCT
  • CAN TELL METEORITES HAVE HIT IN PAST:
    • LAYERS OF UNUSUAL ELEMENTS IN ROCKS - IMPORTED BY ASTEROID
    • SUDDEN CHANGE IN FOSSIL NUMBERS BETWEEN LAYERS OF ROCK - EXTINCTION

COMETS - BALLS OF ROCK, DUST AND ICE THAT ORBIT EARTH IN HIGHLY ELIPTICAL ORBITS

  • COME FROM OBJECTS ORBITING SUN WAY BEYOND PLANETS
  • COMET APPROACHES SUN - ICE MELTS - BRIGHT TAIL OF GAS AND DEBRIS - CAN BE MILLIONS OF KM LONG - WHAT WE SEE FROM EARTH
  • SPEEDS UP AS APPROACHES SUN - MORE GRAVITATIONAL PULL
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P2G - Threats to Earth

NEAR-EARTH OBJECTS - ASTROIDS OR COMETS THAT MIGHT BE ON COLLISION COURSE WITH EARTH

  • POWERFUL TELESCOPES AND SATELLITES USED TO MONITOR THEM - WHEN OBJECT FOUND, TRAJECTORY CALCULATED TO SEE IF ON COLLISION COURSE WITH EARTH
  • SMALL NEOS - BURN UP HARMLESSLY IN ATMOSPHERE - LARGER ONES - CAUSE EXPLOSIONS MORE POWERFUL THAN NUCLEAR WEAPONS
  • IF GET WARNING - TRY TO DEFLECT IT BEFORE COLLISION
  • EXPLODE BOMB NEAR IT - NUDGE IT OFF COURSE
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P2H - The Big Bang

EVIDENT EXPANSION OF UNIVERSE

  • LOOKS LIKE IT'S GETTING BIGGER - GALAXIES MOVING AWAY FROM EACHOTHER - EVIDENCE:
  • LIGHT FROM DISTANT GALAXIES RED SHIFTED - 
    • LIGHT FROM DISTANT GALAXIES - FREQUENCIES LOWER THAN SHOULD BE - SHIFTED TOWARDS RED END OF SPECTRUM
    • SAME EFFECT AS CAR HORN SOUNDING LOWER PITCHED WHEN MOVING AWAY - DROPS FREQUENCY
    • MEASUREMENTS OF RED SHIFT - SUGGESTS ALL GALAXIES MOVING AWAY FROM US VERY QUICKLY - SAME IN EVERY DIRECTION
  • MORE DISTANT GALAXIES HAVE GREATER RED SHIFTS
    • MORE DISTANT GALAXIES MOVING AWAY FASTER THAN NEARER ONES - WHOLE UNIVERSE EXPANDING

EVIDENT COSMIC BACKGROUND RADIATION

  • LOW FREQUENCY MICROWAVE RADIATION COMING FROM ALL DIRECTIONS AND ALL PARTS OF UNIVERSE - COSMIC BACKGROUND RADIATION
  • EVIDENCE FOR BIG BANG - UNIVERSE EXPANDS AND COOLS - BACKGROUND RADIATION COOLS AND DROPS FREQUENCY
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P2H - The Big Bang

THE BIG BANG THEORY

  • INITIALLY, ALL MATTER IN UNIVERSE OCCUPIED VERY SMALL SPACE - SMALLER THAN PINHEAD - THEN EXPLODED - SPACE STARTED EXPANDING - EXPANSION STILL GOING ON
  • LETS US GUESS AGE OF UNIVERSE - RATE OF CURRENT EXPANSION - 14 BILLION YEARS OLD
  • HARD TO ESTIMATE - HARD TO TELL WHETHER SPEED OF EXPANSION CHANGED SINCE BIG BANG

ANCIENT GREEK MODEL OF UNIVERSE - GEOCENTRIC

  • BELIEVED SUN, MOON, PLANETS AND STARS OBITTED EARTH - GEOCENTRIC MODEL
  • ACCEPTED MODEL OF UNIVERSE FROM ACIENT GREEK TIME TO 1500'S

COPERNIAN MODEL - HELIOCENTRIC

  • STATES THAT PLANETS ORBIT SUN IN PERFECT CIRCLES - INTRODUCED BY COPERNUS IN 1543 - BOOK SHOWED ASTRONOMICAL OBSERVATIONS WHICH COULD BE EXPLAINED WITHOUT EARTH CENTRE
  • EVIDENCE - STARS NEVER MOVED AWAY FROM JUPITER - CARRIED ALONG WITH PLANET - SUGGESTED THEY WERE MOONS - NOT EVERYTHING IN ORBIT AROUND EARTH
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P2H - The Big Bang

GALILEO 

  • 1610 - NOTICED THAT VENUS HAD PHASES - DIFFERENT AMOUNT OF PLANET HIT BY SUN AT DIFFERENT TIMES
  • IF PTOLEMIC MODEL RIGHT, CHANGES WOULD BE VERY SMALL - VENUS ALWAYS IN FRONT OF SUN
  • IF CAPERNICUS MODEL RIGHT, VENUS MOVE IN FRONT OF AND BEHIND SUN - CHANGES BIG - RIGHT
  • COPERNICUS IDEAS NOT POPULAR AT TIME - PREVIOUS MODEL BEEN AROUND LONG TIME
  • MODEL CONDEMNED BY CHURCH - WENT AGAINST BIBLE - STATED EARTH AT CENTRE OF UNIVERSE
  • EVIDENCE OF COPERNICUS MODEL INCREASED WITH TECHNOLOGICAL ADVANCES
  • CURRENT MODEL STILL SAYS SUN AT CENTRE BUT THAT PLANET ORBITS ELIPTICAL
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P2H - The Big Bang

(http://students.um.edu.mt/icil0002/Pics/Life%20Cycle%20of%20a%20Star.gif)

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P2H - The Big Bang

  • INITIALLY FORM FROM CLOUDS OF DUST AND GAS - FORCE OF GRAVITY MAKES IT SPIRAL TOGETHER TO FORM PROTOSTAR - GRAVITATIONAL ENERGY CONVERTED TO HEAT ENERGY - STAR HEATS UP
  • TEMP HIGH ENOUGH - HYDROGEN NUCLEI UNDERGO THERMONUCLEAR FUSION - FORM HELIUM NUCLEI, HEAT, LIGHT - ENTERS STABLE PERIOD (MAIN SEQUENCE) - HEAT CREATED BY NUCLEAR FUSION PROVIDES OUTWARD FORCE TO BALANCE GRAVITY PULLING INWARDS - BILLIONS OF YEARS
  • HYDROGEN BEGINS TO RUN OUT - STAR SWELLS INTO RED GIANT - BECOMES RED AS SURFACE COOLS
  • SMALL OR MEDIUM SIZED STAR - BECOMES UNSTABLE - EJECTS OUTER LAYER OF DUST AS PLANETARY NEBULA - LEAVES BEHIND HOT, DENSE CORE (WHITE DWARF) - COOLS DOWN AND FADES AWAY
  • BIG STARS - RED GIANTS - GLOW BRIGHTLY AGAIN, UNDERGO MORE FUSION, EXPAND AND CONTRACT SEVERAL TIMES - FORM HEAVIER ELEMENTS IN VARIOUS NUCLEAR REACTIONS - EVENTUALLY EXPLODE TO FORM SUPERNOVA 
  • EXPLODING SUPERNOVE THROWS OUTER LAYER OF DUST AND GAS INTO SPACE - ERY DENSE CORE (NEUTRON STAR) - IF STAR BIG ENOUGH, IT BECOMES A BLACK HOLE
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