2. 26/09/2016 Living for the Future W Richards (OCR Gateway Additional Science)

3. 26/09/2016 P2a Collecting Energy from the Sun

4. 26/09/2016 Solar Panels and Thermal Towers What are the advantages and disadvantages of solar power?

5. 26/09/2016 Using Solar Energy in remote places

6. 26/09/2016 Solar Energy Solar panels – convert sunlight directly into ______. Sunlight knocks ______ loose from the crystal structure and the loose electrons form a DC electric ______. The amount of power depends on the ___ of the panel and the light ______ and the distance to the ____. Words – current, electricity, electrons, sun, area, intensity

7. 26/09/2016 Other ways to use solar energy Heating for homes – these pipes carry water that absorbs heat energy and transfers it to the house. Using curved mirrors and solar panels – these curved mirrors focus light onto a chosen point and efficient ones can track the sun across the sky Wind power – heat from the sun causes convection currents which then form wind. What are the advantages and disadvantages of wind power?

8. 26/09/2016 Passive solar heating “Passive solar heating” is the idea of using solar power to heat homes. Here’s how they work: 1)Glass is transparent to the sun’s radiation 2)The “thermal mass” next to the glass absorbs the sun’s heat energy 3)The surface then emits radiation of longer wavelength 4)The glass helps reflect the infra red back inside the house

9. 26/09/2016 P2b Generating Electricity

10. 26/09/2016 DC and AC DC stands for “Direct Current” – the current only flows in one direction. Batteries supply DC. AC stands for “Alternating Current” – the current changes direction 50 times every second (frequency = 50Hz). Household electricity is AC 1/50 th s 230V V V Time T

11. 26/09/2016 Generating Electricity The direction of the generated current is reversed if… 1)The magnet is moved in the opposite direction 2)The other pole is inserted first The size of the generated current can be increased by: 1)Increasing the speed of movement 2)Increasing the magnet strength 3)Increasing the number of turns on the coil

12. 26/09/2016 AC Generator Induced current can be increased in 4 ways: 1)Increasing the speed of movement 2)Increasing the magnetic field strength 3)Increasing the number of turns on the coil 4)Increasing the area of the coil NS NS Current Time

13. 26/09/2016 Using non-renewable fuels in power stations 1) A fossil fuel is burned in the boiler 2) Water turns to steam and the steam drives a turbine 3) The turbine turns a generator 4) The output of the generator is connected to a transformer 5) The steam is cooled down in a cooling tower and the electricity is sent into the National Grid

14. 26/09/2016Efficiency Efficiency is a measure of how much USEFUL energy you get out of an object from the energy you put INTO it. For example, consider a TV: Electrical Energy (200J) Light (80J) Sound (40J) Heat (?) Efficiency = Useful energy out Energy in x100%

15. 26/09/2016 Some examples of efficiency… 1)5000J of electrical energy are put into a motor. The motor converts this into 100J of movement energy. How efficient is it? 2)A laptop can convert 400J of electrical energy into 240J of light and sound. What is its efficiency? Where does the rest of the energy go? 3)A power station is 50% efficient. If it delivers 20,000J of electrical energy how much chemical energy was put into it?

16. 26/09/2016 Efficiency of Power Stations 100J Boiler 85J Turbine 35J Generator 30J 15J 50J 5J Heat Kinetic Heat Electrical What is the efficiency at each stage of this power station?

17. 26/09/2016 P2c Global Warming The following two graphs are taken from Wikipedia. What do they imply?

18. 26/09/2016

20. The Greenhouse Effect We get heat from the sun: Here’s how the greenhouse effect works: 1)Our atmosphere absorbs a lot of infra red ________ from the sun 2)Short wavelength EM radiation from the sun is absorbed by the _______ and heats it up 3)The Earth re-radiates heat as _______ wavelength EM radiation (i.e. _______ _____) 4)Greenhouse gases such as _____, carbon dioxide and water vapour absorb some of this infra red and re-radiate it back to the Earth causing it to ______ up. Words – longer, radiation, Earth, warm, infra red, atmosphere

21. 26/09/2016 The Changing Greenhouse Effect The Greenhouse Effect has been around for millions of years but scientists are concerned that it has been increasing in recent decades. How have the following things affected this? DeforestationFactory pollutionVolcanoes

22. 26/09/2016 Differing views on Global Warming The following data shows global warming figures and projections from different research centres. What do you notice?

23. 26/09/2016 P2d Fuels for Power

24. 26/09/2016Fuels A “fuel” is something that can be burned to release heat and light energy. The main examples are: Coal, oil and gas are called “fossil fuels”. In other words, they were made from fossils.

25. 26/09/2016 Nuclear power stations These work in a similar way to normal power stations: The main difference is that the nuclear fuel (uranium) is NOT burnt – it is used to boil water in a “heat exchanger”

26. 26/09/2016 Biomass “Biomass” is a term used to describe anything that can be grown or biologically made and then burned as a fuel:

27. 26/09/2016 Non-renewable energy sources Coal, oil, gas and nuclear AdvantagesDisadvantages Cheap fuel costs Short start-up time for gas and oil Good for “basic demand” Fuel will run out Costs a lot of money to decommission a nuclear plant Pollution – CO 2 leads to global warming and SO 2 leads to acid rain Reliable Nuclear produces little pollution

28. 26/09/2016 Renewable energy sources summary Wind, tidal, hydroelectric and solar AdvantagesDisadvantages Zero fuel costs Hydroelectric is good for a “sudden” demand Don’t produce pollution Ugly and the energy produced by them is very “dilute” Unreliable (except for hydroelectric) Expensive to build Solar is good for remote locations (e.g. satellites)

29. 26/09/2016 Energy and Power The POWER RATING of an appliance is simply how much energy it uses every second. In other words, 1 Watt = 1 Joule per second E TP E = Energy (in joules) P = Power (in watts) T = Time (in seconds)

30. 26/09/2016 Some example questions 1)What is the power rating of a light bulb that transfers 120 joules of energy in 2 seconds? 2)What is the power of an electric fire that transfers 10,000J of energy in 5 seconds? 3)Rob runs up the stairs in 5 seconds. If he transfers 1,000,000J of energy in this time what is his power rating? 4)How much energy does a 150W light bulb transfer in a) one second, b) one minute? 5)Jonny’s brain needs energy supplied to it at a rate of 40W. How much energy does it need during a 50 minute physics lesson? 6)Lloyd’s brain, being more intelligent, only needs energy at a rate of about 20W. How much energy would his brain use in a normal day? 60W 2KW 150J, 9KJ 120KJ 630MJ 0.2MW

31. 26/09/2016 The Cost of Electricity Electricity is measured in units called “kilowatt hours” (kWh). For example… A 3kW fire left on for 1 hour uses 3kWh of energy A 1kW toaster left on for 2 hours uses 2kWh A 0.5kW hoover left on for 4 hours uses __kWh A 200W TV left on for 5 hours uses __kWh A 2kW kettle left on for 15 minutes uses __kWh

32. 26/09/2016 The Cost of Electricity To work out how much a device costs we do the following: Cost of electricity = Power (kW) x time (h) x cost per kWh (p) For example, if electricity costs 12p per unit calculate the cost of the following… 1)A 2kW fire left on for 3 hours 2)A 0.2kW TV left on for 5 hours 3)A 0.1kW light bulb left on for 10 hours 4)A 0.5kW hoover left on for 1 hour 72p 12p 6p Electricity is cheaper at night time (around 5p per unit) – how much would these devices cost at night time?

33. 26/09/2016 Power Power is “the rate of doing work”. The amount of power being used in an electrical circuit is given by: P IV Power = voltage x current in W in V in A We can use this equation to analyse power stations: 1)A transformer gives out 10A at a voltage of 50V. What is its power output? 2)An electric fire has a power rating of 2KW. If it runs on a voltage of 230V what is the current? 3)Electricity is transmitted along some lines in the National Grid at 400KV. If the current is 1KA what would be the power through the wire? 500W 8.7A 400MW

34. 26/09/2016 The National Grid Electricity reaches our homes from power stations through the National Grid: If electricity companies transmitted electricity at 240 volts through overhead power lines there would be too much ______ loss by the time electricity reaches our homes. This is because the current is ___. To overcome this they use devices called transformers to “step up” the voltage onto the power lines. They then “____ ____” the voltage at the end of the power lines before it reaches our homes. This way the voltage is _____ and the current and power loss are both ____. Words – step down, high, power, low, high Power station Step up transformer Step down transformer Homes

35. 26/09/2016 P2e Nuclear Radiations

36. 26/09/2016 The structure of the atom ELECTRON – negative, mass nearly nothing PROTON – positive, same mass as neutron (“1”) NEUTRON – neutral, same mass as proton (“1”)

37. 26/09/2016 Introduction to Radioactivity Some substances are classed as “radioactive” – this means that they are unstable and continuously give out radiation: Radiation The nucleus is more stable after emitting some radiation – this is called “radioactive decay”.

38. 26/09/2016 Background Radiation Radon gas Food Cosmic rays Gamma rays Medical Nuclear power 13% are man-made

39. 26/09/2016 Blocking Radiation Each type of radiation can be blocked by different materials:    Sheet of paper Few mm of aluminium Few cm of lead

40. 26/09/2016Ionisation Radiation is dangerous because it “ionises” atoms – in other words, it turns them into positive ions by “knocking off” electrons or negative ions by gaining electrons: Alpha radiation is the most ionising (basically, because it’s the biggest). Ionisation causes cells in living tissue to mutate, usually causing cancer.

41. 26/09/2016 Uses of Alpha Radiation Smoke detectors Alarm +ve electrode -ve electrode Alpha emitter Ionised air particles If smoke enters here a current no longer flows

42. 26/09/2016 Uses of Beta Radiation Rollers Beta emitter Beta detector Paper

43. 26/09/2016 Uses of Gamma Radiation Sterilising medical instruments Gamma rays can be used to kill and sterilise germs without the need for heating.

44. 26/09/2016 Other uses of radioactivity 1) Medical uses – gamma rays can be used to destroy cancerous cells 2) Tracers – a tracer is a small amount of radioactive material used to detect things, e.g. a leak in a pipe: Gamma source Tracers can also be used to develop better plant fertilisers and in medicine to detect tumours: The radiation from the radioactive source is picked up above the ground, enabling the leak in the pipe to be detected.

45. 26/09/2016 Handling Radioactive Materials Safety measures: 1)Keep your distance 2)Minimise exposure time 3)Protective clothing 4)Careful labelling Plutonium is a waste product from nuclear power stations and can be used to make nuclear bombs. It remains radioactive for a long time and can be a terrorist risk.

46. 26/09/2016 Disposing of radioactive waste High level waste is immobilised by mixing with ____ making ingredients, melting and pouring the glass into steel containers. Intermediate waste is set in cement in _____ drums. The key to dealing with radioactive waste is to IMMOBILISE it. There are a number of ways of doing this depending on how __________ the waste is: The containers are then kept in stores, often _________. Words – glass, steel, underground, radioactive

47. 26/09/2016 P2f Exploring our Solar System

48. 26/09/2016 The Solar System summarised What makes up our solar system? Complete the following mind map with what you now about each object: The solar system

49. 26/09/2016 The eight planets of our Solar System Mercury Mars Jupiter Saturn Neptune Uranus Venus Earth As well as the eight planets, the solar system is also made up of asteroids, dwarf planets, comets and moons

50. 26/09/2016 Distances in space The Sun, our closest star, is 1.6x10 -5 light years away from us. The Andromeda Galaxy (our closest galaxy) – approximately 2.5 million light years away The next closest star, Proxima Centauri (4.2 light years away) The centre of our galaxy, the Milky Way, is around 26,000 light years away. Definition – a “light year” is the distance covered by light every year

51. 26/09/2016 Solar systems, galaxies and the Universe OUR SUN (100 times wider and 4.6 billion years old), which is small compared to… THE MILKY WAY, which contains at least 200 billion stars and is 100,000 light years across, which is small compared to… Our planet (around 13,000km diameter and 4500 million years old) is pretty small compared to... THE UNIVERSE, which contains billions of galaxies and is 14,000 million years old.

52. 26/09/2016 How our Earth and the Sun compare to others… 26/09/2016

57. Elliptical Orbits Ellipse

58. 26/09/2016 The Earth is kept in orbit by 2 things… Gravity …and by the fact that it is moving at a high velocity This is called a “centripetal force”

59. 26/09/2016 Searching for Aliens Humans have been searching for me for over 50 years. Here are some of the methods they use: SETI – The Search for Extra Terrestrial Intelligence Since 1960 a group of astronomers have collectively been sending out EM signals hoping that someone will send one back! Space probes The Voyager 1 probe, still in operation after over 33 years and still sending signals back to Earth. Soil samples Soil samples from the moon and, in recent years, from Mars have been sampled. What are the advantages and disadvantages of each of these methods?

60. 26/09/2016 Space Travel Manned space travel Unmanned space travel AdvantagesDisadvantages

61. 26/09/2016 P2g Threats to the Earth

62. 26/09/2016 The moon The moon may be the remians of a very old planet. The Earth-Moon system was formed due to a collision between them many years ago: When this collision happened the iron cores merged to form the core of the Earth and the less dense material ended up being in the moon. There are two main areas of evidence for this: 1)Similarities in the composition of rocks on the Earth and moon 2)The Earth’s iron core is much bigger than the moon’s

63. 26/09/2016Asteroids An “asteroid belt” lies between Mars and Jupiter. But what is an asteroid? An asteroid is a rock left over from the formation of the solar system. They are between Jupiter and Mars because the gravitational attraction of Jupiter disrupted the formation of a planet.

64. 26/09/2016Asteroids 1)If an asteroid hit the Earth what effect would it have? 2)Many asteroids have already hit the Earth over many years – how do we know?

65. 26/09/2016 Oh no… Effects of Asteroid collisions The following things are possible consequences of an asteroid collision: 1)Extinction 2)Climate change 3)Sunlight blocked by dust 4)Craters 5)Widespread fires As well as craters, evidence for asteroid collisions can also be seen by finding unusual elements in rocks and sudden changes in fossil numbers in adjacent rocks.

66. 26/09/2016Comets Comets are balls of dust and frozen gas. They have very elliptical orbits: As the comet approaches the sun gases evaporate from it, forming a “tail”. This tail always faces AWAY from the sun. The comet also goes faster near the sun due to an increased gravitational attraction.

67. 26/09/2016 Near Earth Objects A Near Earth Object (NEO) is an asteroid or comet on a possible collision course with the Earth. How can we monitor and deal with Near Earth Objects?

68. 26/09/2016 P2h The Big Bang

69. 26/09/2016 Evidence about the origins of the universe…

70. 26/09/2016 Source of light “Spectra”

71. 26/09/2016 If you pass the light through a gas something different is seen… helium Some wavelengths of light are absorbed by the gas – an “absorption spectrum”.

72. 26/09/2016 After helium If the light source is moving away the absorption spectra look a little different… helium Before

73. 26/09/2016 The absorption lines have all been “shifted” towards the longer wavelength end (red end)… After Before A similar effect happens with sound – this is called “The Doppler Effect” This is called red shift. The faster the light source moves the further its light will be “shifted”

74. 26/09/2016 Red Shift simplified Basically, if I walk towards you I’ll look slightly more blue. Then, if I walk away from you, I’ll look slightly more red!! Let’s try it…

75. 26/09/2016

77. Doppler Effect explained

78. 26/09/2016 Light from different stars and from the edge of the universe also shows this “red-shift”. This suggests that everything in the universe is moving away from a single point. This is the BIG BANG theory

79. 26/09/2016 Red shift summary Light from other galaxies has a longer _________ than expected. This shows that these galaxies are moving ____ from us very quickly. This effect is seen to a greater extent in galaxies that are _______ away from us. This indicates that the further away the galaxy is, the ______ it is moving. Words to use – faster, away, big bang, billion, wavelength, further This evidence seems to suggest that everything in the universe is moving away from a single point, and that this process started around 15 _____ years ago. This is the ____ ________ Theory.

80. 26/09/2016 Cosmic Microwave Background Radiation 26/09/2016 Further evidence of the Big Bang theory is Cosmic Microwave Background Radiation (CMBR) – this radiation comes from the Big Bang and fills the _________. Basically, at the start of the universe, radiation was hot and had high _______. As time went on the ________and energy of this radiation dropped which turned it into to ________. This “background microwave _______” is all over the universe. Words – microwaves, frequency, temperature, universe, radiation

81. 26/09/2016 The Life Cycle of a Star

82. 26/09/2016 Stage 1: Nebulae A nebulae is a collection of dust, gas and rock. Some examples of nebulae…

83. 26/09/2016 Dark nebula

84. 26/09/2016 Emission nebula

85. 26/09/2016 Reflection nebula

86. 26/09/2016 Planetary nebula (This nebula is smaller and will only form a planet)

87. 26/09/2016 Gravity will slowly pull these particles together… As they move inwards their gravitational potential energy is converted into heat and a PROTOSTAR is formed Stage 2: Protostar

88. 26/09/2016 Stage 3: Main Sequence Our sun is an example of a main sequence star – it’s in the middle of a 10 billion year life span In a main sequence star the forces of attraction pulling the particles inwards are _________ by forces acting outwards due to the huge __________ inside the star. Stars are basically ________ reactors that use _______ as a fuel. During its main sequence a star will release energy by converting hydrogen and helium (light elements) into _________ elements and this is why the universe now contains a number of heavier elements. Words – heavier, balanced, hydrogen, nuclear, temperatures

89. 26/09/2016 Eventually the hydrogen and helium will run out. When this happens the star will become colder and redder and start to swell… If the star is relatively small (like our sun) the star will become a RED GIANT If the star is big (at least 4 times the size of our sun) it will become a RED SUPERGIANT Stage 4: Red Giant

90. 26/09/2016 What happens at this point depends on the size of the star… 1) For SMALL stars the red giant will collapse under its own gravity and form a very dense white dwarf: Stage 5: The Death White dwarfBlack dwarf Red giant

91. 26/09/2016 2) If the star was a RED SUPERGIANT it will shrink and then EXPLODE, releasing massive amounts of energy, dust and gas. AfterBefore This explosion is called a SUPERNOVA

92. 26/09/2016 The dust and gas on the outside of the supernova are thrown away by the explosion and the remaining core turns into a NEUTRON STAR. If the star is big enough it could become a BLACK HOLE instead.

93. 26/09/2016 Black Holes A black hole is an object that is so small and dense that its escape velocity is greater than the speed of light. In other words, not even light can escape its gravitational pull. Fascinating

94. 26/09/2016 The dust and gas thrown out by a supernova can be used to form a new star… Stage 6: Second generation stars Our sun is believed to be a “______ ______ star” – this is because it contains some __________ elements along with hydrogen and ________. These heavier elements would have been the products of a previous star that have been thrown out by a ________. These heavier elements are also found on planets, indicating that they might have been made from remains of previous _______ as well. Words – helium, heavier, second generation, stars, supernova

95. 26/09/2016 The Life Cycle of a Star summary Protostar Main sequence Red super giant Supernova Red giant White dwarf Black dwarfNeutron starBlack hole Basically, it all depends on the size of the star! SMALL stars BIG stars

96. 26/09/2016 Our understanding of the universe Ptolemy, AD 90-168Copernicus, 1473-1543 Up until the 16 th Century people believed that the Earth was the centre of the universe – this is called the “Geocentric model” and I made a model of the universe based on it. I published my “On the revolutions of the celestial spheres” just before my death and showed that the Earth and other planets orbit around the sun – the “Heliocentric model”.

97. 26/09/2016 Evidence for the Heliocentric Model Galileo, 1564-1642 Jupiter and its moons, as seen through a telescope The orbits of these moons I helped develop the modern telescope and made measurements with it that proved that the Copernican model of the solar system was correct but a lot of people didn’t like it because the old Catholic Church didn’t like it.