27/05/13DiffusionDiffusionDiffusion is when something travels from an area of highconcentration to an area of low concentration. For example,consider the scent from a hamburger…The “scent particles” fromthis hamburger are in highconcentration here:Eventually they will“diffuse” out into this areaof low concentration:
27/05/13DiffusionDiffusionCells use diffusion to swapthe oxygen they need forthe carbon dioxide theyno longer want:Other examples of where diffusion happens in humans:Alveoli in the lungs Villi in the intestinesOxygendiffuses inOut goeswaste CO2
27/05/13The digestive systemThe digestive systemThe whole point of digestion is to break down our food sothat we can get the bits we need from it…The main foodsaffected areCARBOHYDRATES –these are broken downinto GLUCOSE
27/05/13EnzymesEnzymesEnzymes are chemicals produced by the body to help_______. When they react with food they break it downinto ______ pieces which can then pass into the ______:Carbohydrase (produced in the mouth,pancreas and small intestine) breaks_______ (a carbohydrate) down intoglucose:Protease (produced in the stomach,pancreas and small intestine) breaks_______ down into amino acids:Lipase (produced in the pancreas andsmall intestine) breaks fats (_____)down into fatty acids and glycerol:Words – blood, lipids, proteins, digestion, starch, smallerBloodstream
27/05/13A closer look at alveoli:A closer look at alveoli:TracheaBronchiBronchiolesAlveoli
27/05/13Gas exchangeGas exchangeAlveoli are very good at exchanging gases because…1) They have a LARGE surface area2) They have a good blood supply3) They are moist
27/05/13RespirationRespirationRespiration is the chemical reaction the cells in our bodiesuse to release ________. The equation:Glucose + _____ Carbon dioxide + _____ + ENERGYGlucose is provided by ______ and oxygen is provided whenwe __________. The energy we obtain from this reactionwas originally contained inside the ________ molecules andis released when the bonds are ________.The energy produced by respiration is used for building andrepairing _____, movement, transporting materials across__________ and maintaining a constant ___________.Words – water, temperature, membrane, broken,food, energy, oxygen, glucose, breathe, cells
27/05/13Anaerobic respirationAnaerobic respirationUnlike aerobic respiration, anaerobic respiration is whenenergy is provided WITHOUT needing _________:This happens when the body can’t provide oxygen quick enoughfor __________ respiration to take place.Anaerobic respiration produces energy much _______ thanaerobic respiration but only produces 1/20thas much.Lactic acid is also produced, and this can build up in musclescausing ______ and an oxygen ______.This “debt” then needs to be “repaid” by deep breathing to________ the lactic acid.Words – debt, oxygen, fatigue, oxidise, aerobic, quickerGlucose lactic acid + a bit of energy
27/05/13The four parts of bloodThe four parts of blood1. RED BLOOD CELLS – contain haemoglobinand carry ______ around the body. Theyhave no _______ and a large surface area.2. PLATELETS – small bits of cells that liearound waiting for a cut to happen so thatthey can ____ (for a scab).3. WHITE BLOOD CELLS – kill invading_______ by producing _________ orengulfing (“eating”) the microbe.These three are all carried around by thePLASMA (a straw-coloured liquid). Plasmatransports CO2 and ______ as well as takingaway waste products to the ______.Words – antibodies, clot, kidneys,oxygen, nucleus, glucose, microbes.
27/05/13Section 2Section 2Maintenance of LifeMaintenance of Life
27/05/13PhotosynthesisPhotosynthesisPHOTOSYNTHESIS is when a plant makes its own food.Photosynthesis USES:Carbon dioxideWaterEnergy (from the sun)Photosynthesis PRODUCES:OxygenGlucose
27/05/13Four things are needed for photosynthesis:Travels upfrom the rootsWATERCARBON DIOXIDEEnters the leaf through smallholes on the underneathSUNLIGHTGives the plant energyCHLOROPHYLLThe greenstuffwhere thechemicalreactionshappen
27/05/13The word and chemical equations for photosynthesis:Carbon dioxide + water glucose + oxygen6CO2 + 6H20 C6H12O6 + 6O2SunlightChlorophyllSunlightChlorophyllGlucose (sugar) can be used to make long chains of starch…GlucosemoleculesStarchmolecule
27/05/13Three factors can affect photosynthesis:Three factors can affect photosynthesis:1. Temperature – the best temperature isabout 300C – anything above 400C will slowphotosynthesis right down2. CO2 – if there is more carbon dioxidephotosynthesis will happen quicker3. Light – if there is more lightphotosynthesis happens faster
27/05/13Drawing graphs of these factorsDrawing graphs of these factors1. TemperaturePhotosynthesis is controlled byenzymes – these are destroyedat temperatures above 400C2. Carbon dioxide3. LightPhotosynthesis increases atfirst but is then limited by alack of increase in temp or CO2Photosynthesis increases atfirst but is then limited by alack of increase in temp or light
27/05/13HomeostasisHomeostasisHomeostasis means “controlling internal conditions”:Waste products that need to be removed + howCO2UreaInternal conditions that need controlling + howTemperatureIon contentWater contentProduced by respiration, removed via lungsProduced by liver breaking down amino acids,removed by kidneys and transferred to bladderIncreased by shivering, lost by sweatingIncreased by eating, lost by sweating + urineIncreased by drinking, lost by sweating + urineSome of these processes are controlled by HORMONES. Hormones arechemical messengers produced by glands and transported in the blood.
27/05/13KidneysKidneysBlood inBlood outUreter (tube that takesurine down to bladder)Kidneys are made up of twoimportant tissues – BLOODVESSELS and TUBULES.Kidneys are responsible for controlling ion, urea andwater content.
27/05/13KidneysKidneysKidneys work in 3 stages:1. ULTRAFILTRATION - Lots of water andproducts of digestion are squeezed out ofthe blood and into tubules under pressure.3. WASTE – excess water, excess ions andany urea are now removed through theureter2. SELECTIVE REABSORPTION – the bloodtakes back the things it wants (e.g. glucoseand ions) even though this means goingagainst a concentration gradient.Blood vessel Tubule
27/05/13Controlling water contentControlling water contentThe amount of water reabsorbed into the blood vessels inthe kidney is controlled by the hormone ADH:
27/05/13Controlling body temperatureControlling body temperatureBody temperature is controlled by the thermo-regulatorycentre in the ________. It is kept at 370C as this is thebest temperature for __________ to work in. If the bodybecomes too hot then blood vessels _________ and sweatglands release ________. If the body is too ______ thenblood vessels constrict and muscles start to __________.Words – sweat, enzymes, cold, dilate, shiver, brain
27/05/13Group 1 – The alkali metalsGroup 1 – The alkali metalsLiNaKRbCsFr
27/05/13Group 1 – The alkali metalsGroup 1 – The alkali metals1) These metals all have to bestored under ____ because theyreact with _______Some facts…2) Reactivity increases as you go _______ the group. This isbecause the electrons are further away from the _______every time a _____ is added, so they are given up more easily.3) They all react with water to form an alkali (hence theirname) and __________, e.g:Words – down, oil, shell, hydrogen, nucleus, waterPotassium + water potassium hydroxide + hydrogen
27/05/13The Transition MetalsThe Transition Metals1) This section includes metals like gold, mercury, iron, copperSome facts…2) They are all ______ and solid (except _________)3) They are ____ reactive than the alkali metalsWords – hard, coloured, mercury, less4) They can form __________ compounds
27/05/13Displacement ReactionsDisplacement ReactionsA displacement reaction is where a more reactive metal will displace aless reactive metal from one of its compounds.e.g.Predict the following reactions:1) Lead + copper chloride2) Silver + copper chloride3) Magnesium + iron oxide4) Aluminium + copper sulphate5) Zinc + lead nitratePotassiumSodiumCalciumMagnesiumAluminiumZincIronTinLeadCopperSilverGoldPlatinum
27/05/13Extracting MetalsExtracting MetalsSome definitions:A METAL ORE is a mineral or mixture of minerals fromwhich it is “economically viable” to extract some metal.Most ores contain METAL OXIDES (e.g. rust = iron oxide).To “extract” a metal from a metal oxide we need toREDUCE the oxygen. This is called a REDUCTIONreaction.
27/05/13How do we do it?How do we do it?PotassiumSodiumCalciumMagnesiumAluminiumCarbonZincIronTinLeadCopperSilverGoldPlatinumMetals ABOVE CARBON, becauseof their high reactivity, areextracted by ELECTROLYSISMetals BELOW CARBON areextracted by heating them withcarbon in a BLAST FURNACEThese LOW REACTIVITY metalsblatantly won’t need to be extractedbecause they are SO unreactive you’llfind them on their own, not in a metaloxide
27/05/13Extracting metalsExtracting metals1) What is an ore?2) In what form are metals usually found in the Earth?3) How do you get a metal out of a metal oxide?4) What is this type of reaction called?Type of metal Extraction process ExamplesHigh reactivity (i.eanything above carbon)Middle reactivity (i.e.anything below carbon)Low reactivity
27/05/13Acids and alkalisAcids and alkalisUsing a Universal Indicator we can detect what pH asolution is by observing the colour:1 2 3 4 5 6 7 8 9 10 11 12 13 141 2 3 4 5 6 7 8 9 10 11 12 1314
27/05/13Hydrocarbons and crude oilHydrocarbons and crude oilLonger chains mean…1. Less ability to flow2. Less flammable3. Less volatile4. Higher boiling pointIncreasinglengthCrude oil is a mixture of HYDROCARBONS(compounds made up of carbon and hydrogen).Some examples:EthaneC CHHHHHHButaneC CHH HHHH C C HHHH
27/05/13Fractional distillationFractional distillationCrude oil can be separated by fractional distillation. The oil is evaporatedand the hydrocarbon chains of different lengths condense at differenttemperatures:Fractions withlow boilingpoints condenseat the topFractions withhigh boilingpoints condenseat the bottom
27/05/13CrackingCrackingShorter chain hydrocarbons are in greater demand becausethey burn easier. They can be made from long chainhydrocarbons by “cracking”:ButaneEthaneEthaneFor example, this bondcan be “cracked” to givetwo of these:
27/05/13CrackingCrackingThis is a THERMAL DECOMPOSITION reaction,with clay used as a catalyst1) Carbon dioxide causes the _________ effect2) Sulphur dioxide causes _____ _____3) Plastics are not _____________Cracking is used to produce plastics such as polymers and polyethanes. Thewaste products from this reaction include carbon dioxide, sulphur dioxideand water vapour. There are three main environmental problems here:
27/05/13AlkenesAlkenesAlkenes are different to alkanes; they contain DOUBLECOVALENT bonds. For example:Ethane EtheneButane ButeneThis double bond means that alkenes have the potential to joinwith other molecules – this make them REACTIVE. We cantest for alkenes because they turn bromine water colourless.ALKANESALKENES
27/05/13Carbon dioxide in the atmosphereCarbon dioxide in the atmosphereThe amount of CO2 in the atmosphere is affected by 3 things:1) Geological activity moves carbonate rocks deep intothe Earth and they release ______ _______ into theatmosphere during volcanic activity.2) When fossil fuels are burned the carboncontained in them reacts with _____ to form CO2.3) Increased CO2 in the atmosphere causes a reactionbetween it and _______. These reactions produce two things:INSOLUBLE CARBONATES (which are deposited as ______)and SOLUBLE HYDROGENCARBONATES (which ________ inthe seawater). These reactions do not remove ALL of the newCO2 so the greenhouse effect is still getting _______!Words – oxygen, seawater, carbon dioxide, worse, dissolve, sediment
27/05/13The CrustThe CrustSedimentary rockssettle in layers.The oldest rock isat the bottom.Layers of sedimentary rock can be examined to discover howthey were formed. They are often found folded or fractured:
27/05/13RadiationRadiationWhen you wear a black t-shirt on a hot, sunny day you wouldfeel ______ than if you wore ____. This is because black_______ infrared radiation (i.e. heat) from the sun betterthan white does.I’m very hot!I’m cool!
27/05/13Some examples of radiationSome examples of radiation
27/05/13Some examples of radiationSome examples of radiation
27/05/13Radiation is when heat moves around in electromagnetic _________ likelight does. Any hot object will emit heat radiation – the hotter it is, themore radiation it emits. This type of radiation is called __________, andtoo much of it will cause _________. Dark, matt colours will absorb ANDemit the _____ infra-red radiation, and light, shiny colours will ________it.The main difference with radiation is that conduction and convection couldONLY happen in solids, liquids or gases, whereas radiation will happenthrough an _____ _____. This is just as well, as otherwise we wouldn’t beable to get any heat from the ___.RadiationRadiationWords – sun, reflect, infra-red, waves, most, empty space, sunburnAnything HOT emits HEAT RADIATION – the hotter itis, the more infra red radiation it emits
27/05/13The 9 types of energy and Energy transfersThe 9 types of energy and Energy transfersKinetic (movement)SoundLightHeatNuclearElectricalChemicalGravitationalpotentialElastic potentialWhat are the energy changesof the following devices?1) A TV2) A car engine3) A battery4) An electric motor5) A bow and arrow6) A skier skiing down a hill7) Solar panels
27/05/13EfficiencyEfficiencyEfficiency is a measure of how much USEFUL energy you get out ofan object from the energy you put INTO it.Efficiency = Useful energy given out by the deviceEnergy put into ite.g. if 2000 joules of electrical energy are put into a kettle and 500joules of heat energy are gained from it, its efficiency is 500/2000x 100% = 25%x100%1) How efficient is a 3kW electric fire if it gives out 750W of heat?2) How efficient is a TV that gives out 30J of wasted energy forevery 50J of electrical energy? Where does this waste energygo?
27/05/13Some examples of efficiency…Some examples of efficiency…1) 5000J of electrical energy are put into a motor. Themotor converts this into 100J of movement energy.How efficient is it?2) A laptop can convert 400J of electrical energy into240J of light and sound. What is its efficiency?Where does the rest of the energy go?3) A steam engine is 50% efficient. If it delivers20,000J of movement energy how much chemicalenergy was put into it?
27/05/13Energy Transfer diagramsEnergy Transfer diagramsConsider a light bulb. Let’s say that the bulb runs on 100watts (100 joules per second) and transfers 20 joules persecond into light and the rest into heat. Draw this as adiagram:100 J/selectricalenergy“Input” energy “Output” energy80 J/s heatenergy (given tothe surroundings)20 J/slight energy
27/05/13Example questionsExample questionsConsider a kettle:1) Work out each energy value.2) What is the kettle’sefficiency?SoundenergyWastedheatHeat towater2000 J/selectricalenergyConsider a computer:150 J/selectricalenergy10 J/swastedsound20 J/swastedheatUsefullight andsound1) How much energy is convertedinto useful energy?2) What is the computer’sefficiency?
27/05/13Non-renewable energy sourcesNon-renewable energy sourcesCoal, oil, gas andnuclearAdvantages DisadvantagesCheap fuel costsShort start-up timeGood for “basicdemand”Fuel will runoutCosts a lot ofmoney todecommission anuclear plantPollution – CO2 leads toglobal warming and SO2leads to acid rainReliable
27/05/13Renewable energy sourcesRenewable energy sourcesWind, tidal,hydroelectric and solarAdvantages DisadvantagesZero fuel costsHydroelectricis good for a“sudden”demandDon’t producepollutionTidal barrages destroy thehabitats of wading birdsand hydroelectric schemesinvolve flooding farmlandUnreliable(except forhydroelectric)Expensiveto buildSolar is good forremote locations(e.g. satellites)
27/05/13Renewable energy sourcesRenewable energy sourcesWind – free energy but very “dilute”,depends on weather, visual pollutionTidal – as with wave powerWave – free energy but can harmwildlife and cause visual pollution. Aswith wind, energy is “dilute”Hydroelectric – Can provide instantenergy but can destroy ecosystems
27/05/13Basic ideas…Basic ideas…Electric current is when electrons start to flow around acircuit. We use an _________ to measure it and it ismeasured in ____.Potential difference (also called _______) ishow big the push on the electrons is. We use a________ to measure it and it is measured in______, a unit named after Volta.Resistance is anything that resists an electric current. It ismeasured in _____.”Words: volts, amps, ohms, voltage, ammeter, voltmeter
27/05/13Georg Simon Ohm1789-1854ResistanceResistanceResistance is anything that willRESIST a current. It is measuredin Ohms, a unit named after me.The resistance of a component can becalculated using Ohm’s Law:Resistance = Voltage (in V)(in Ω) Current (in A)VRI
27/05/13An example question:An example question:VA1) What is the resistance acrossthis bulb?2) Assuming all the bulbs are thesame what is the total resistancein this circuit?Voltmeterreads 10VAmmeterreads 2A
27/05/13More examples…More examples…12V3A3A6V4V2A1A2VWhat is theresistance ofthese bulbs?
27/05/13ResistanceResistanceResistance is anything that opposes an electric current.Resistance (Ohms, Ω) = Potential Difference (volts, V)Current (amps, A)What is the resistance of the following:1) A bulb with a voltage of 3V and a current of 1A.2) A resistor with a voltage of 12V and a current of 3A3) A diode with a voltage of 240V and a current of 40A4) A thermistor with a current of 0.5A and a voltage of10V
27/05/13Current-voltage graphsCurrent-voltage graphsIVIVIV1. Resistor 3. Diode2. BulbCurrentincreases inproportion tovoltageWhen current throughthe bulb increases itstemperature increases,thereby increasing itsresistanceBehaves like aresistor, but onlylets current flowin one direction
27/05/13Three simple components:Three simple components:1) Diode – only lets current flow in one direction2) Light dependant resistor – resistance DECREASES whenlight intensity INCREASES3) Thermistor – resistance DECREASES when temperatureINCREASES
27/05/13Examples of electromagnetsExamples of electromagnets1. Speaker 2. Relay switch
27/05/13ElectromagneticElectromagneticinductioninductionThe direction of the inducedcurrent is reversed if…1) The magnet is moved in theopposite direction2) The other pole is insertedfirst
27/05/13ElectromagneticElectromagneticinductioninductionThe size of the induced currentcan be increased by:1) Increasing the speed ofmovement2) Increasing the magnetstrength3) Increasing the number ofturns on the coil
27/05/13AC GeneratorAC GeneratorInduced current can be increased in 4 ways:1) Increasing the speed of movement2) Increasing the magnetic field strength3) Increasing the number of turns on the coil4) Increasing the area of the coil
27/05/13Section 7Section 7Physics in ActionPhysics in Action
27/05/13Electronic systemsElectronic systemsElectronic systems are made up of 3 parts:1) An INPUT SENSOR – these detect changes in theenvironmentExamples:3) An OUTPUT DEVICE – these are controlled by theprocessorExamples:2) A PROCESSOR – these decide what action is neededExamples:
27/05/13RelaysRelaysCircuits such as those containing logic gates only take very ______currents. These circuits may be needed to operate a device that takesa much _____ current, e.g. a _________. To do this the circuit wouldneed a RELAY switch, a device made of an _______ that can operate aswitch. A relay switch is activated by the small current and the switchpart is placed in the circuit needing a large current:Symbolfor relay:Words – motor, larger,electromagnet, smallM
27/05/13Logic gatesLogic gatesLogic gates are the basicsbehind any kind ofprocessor. There are 3that you need to know forGCSE:NOT gate – “the output isNOT what the input is”AND – “the output is on if AAND B are both on”OR – “the output is on if AOR B are on”Input Output0 11 0Input A Input B Output0 0 00 1 01 0 01 1 1Input A Input B Output0 0 00 1 11 0 11 1 1
27/05/13Some problems to solveSome problems to solve• The pump on a central heating system is switched on at roomtemperature if the system is switched on (with the slide switch).When the temperature rises the pump needs to be switched off.• Design a circuit that will sound a buzzer if the temperature of ahot radiator falls during the day ONLY. Include a test switch tocheck the operation of the buzzer.• Design a circuit for a gardener that will warn them of coldconditions at night. The alarm should be able to be switched off.
27/05/13Some example questionsSome example questions0V12VVOUT0V100 Ω100 Ω0V1.5VVOUT0V50 Ω45 Ω0V50VVOUT0V10 Ω75 Ω0V3VVOUT0V75 Ω25 Ω
27/05/13Practical applicationsPractical applications0VVinVOUTHere’s a potentialdivider that is used tocontrol light-activatedswitches…When the light intensity on the LDR decreases itsresistance will ________. This causes VOUT to _______so the processor and output will probably turn _____. Thevariable resistor can be adjusted to change the ________of the whole device.Words – decrease, sensitivity, increase, off
27/05/13The CapacitorThe CapacitorA capacitor is a device that can store charge (it has a“capacity”). It is basically made of two plates:…or…Charge builds up on these plates and the voltagebetween them increases until it reaches the supplyvoltage.
27/05/13Charging and discharging a capacitorCharging and discharging a capacitorP.d. acrosscapacitorTimeP.d.TimeP.d.Time TimeIncreaseresistance orcapacitanceIncreaseresistance orcapacitance
27/05/13Converging and diverging lensesConverging and diverging lensesCONVERGING (Convex)Thickest at the centreDIVERGING (Concave)Thinnest at the centre
27/05/13Ray diagramsRay diagramsThe rays of light arerefracted INWARDS andmeet at the focus, F.The image formed is REAL –in other words, it can beseen on a screenThe rays of light arerefracted OUTWARDS.A VIRTUAL image is formed– in other words, the imagedoesn’t actually existFF
27/05/13Ray diagramsRay diagramsTo draw ray diagrams follow these two rules:1) Draw a ray from the TOP of the object PARALLEL tothe axis and then going through F:2) Draw a ray from the TOPof the object going throughthe CENTRE of the lens(which will be undeviated)FThis image isREAL, UPSIDEDOWN andSMALLER thanthe object