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Description
Flashcards by Alice Hathaway, updated more than 1 year ago
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Created by Alice Hathaway
almost 8 years ago
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| Question | Answer |
| What is the order of the planets in our solar system? | Mercury Venus Earth Mars Jupiter Saturn Uranus Neptune |
| What is between Mars and Jupiter? | Asteroid belt |
| What orbits the sun? | Dwarf Planets Planets Comets Dust Asteroids |
| What orbits planets? | Moons |
| What's the difference between planets and stars? | Stars are much larger, far away, very hot and emit their own light Planets reflect light from the sun, are much smaller and are much closer. |
| How did the sun form? | Dust and gas began to collapse in on itself and gravity took over. They came together at the centre to form a protostar and nuclear fusion began. It gave out huge amounts of heat and light. |
| How did the planets form? | Material in clouds around the sun containing helium, hydrogen and heavier elements clumped together. |
| What is the oldest rock on Earth and how old is it? | Meteorites that crashed into the Earth. They are 4500 million years old. |
| What are asteroids? | Clumps of rock that didn't form planets left over form the formation of our solar system |
| What are comets? | Made of rock dust and ice left over from the solar system formation. They orbit the sun on elongates elipses with the sun at one end, often on a different plane to planets. They form a tail when they get close to the sun as the ice melts. |
| How many stars are in the Milky Way? | 1 x 10^11 |
| What makes up most of the Universe? | Empty space |
| What is a light year? | How far light can travel in a year. Measure of distance. |
| How does parallax work? | Pictures are taken of the sky 6 months apart when the Earth is at opposite sides of its orbit. The closer the star, the greater the apparent movement against distant stars. |
| How can brightness measure distance? | Brightness. However a star can be really bright and far away or dim and close. Scientists know how much radiation is emitted by different types of star therefore by looking at how bright they seem from Earth, they can work out the distance. |
| Why are space telescoped used? | To overcome the issues of the atmosphere absorbing radiation and light; and light pollution making dim objects hard to see. |
| Why do we see stars and galaxies in the past? | Because they are really far away therefore their light takes a long time to reach us. It takes 8 minutes for the sun's light to reach us. The amount of light years away a star is, the amount of years it takes us to see it. |
| What is red shift and how does it show the universe is expanding?? | When galaxies move away, their wavelength changes, becoming redder. The greater the red shift, the faster it's moving away. The more distant the galaxy, the greater the red shift and the faster it is moving away. This shows the universe is expanding. |
| What is the 'Big Bang' theory? | The Universe started from a single point and an explosion caused it to begin expanding. It is still expanding now. Based on the rate of expansion, this probably began about 14,000 million years ago, but is difficult to estimate as we may have slowed down. |
| How could the Universe end? | If there's enough mass compared to the speed of expansion, it will eventually stop and begin contracting , ending in a 'Big Crunch'. If there isn't enough mass compared to speed, it will continue to expand forever into eternity. |
| Why is this difficult to guess? | It is hard to work out the speed of expansion as the Universe is so huge. Also, we don't know the mass due to dark matter being difficult to detect. |
| Why is Earth an 'active planet'? | It's changing all the time |
| What is the rock cycle? | |
| What was believed before Continental Drift? | Land bridges connected continents which sunk under the sea as the Earth cooled. Not every believed this. |
| What did he hypothesise? | There was one super continent - Pangaea- 300 million years ago. This broke into chunks and are still slowly drifting apart. |
| What was Wegener's evidence? | Matching rock layer formation and fossils on South America and Africa. Matching coastlines of South America and Africa |
| Why was his theory rejected at first? | He was a meteorologist He had no mechanism Hostile the huge change Not detectable |
| How did seafloor spreading prove Wegener's theory? | Magma rises up through the the sea floor, solidifies and forms undersea mountains that are symmetrical about the ridge. Showed the sea floor was spreading therefore continents were moving apart. The alternating polarity shows this too. |
| How do volcanoes form? | At boundaries, plates meet and magma is produced, which can rise up. |
| How do earthquakes occur? | The plates move very suddenly, rubbing together and causing an earthquake. |
| How are mountains formed? | Plates crash into each other - one goes up and one goes down. This contributes to the rock cycle |
| What are seismic waves? | Waves produced by earthquakes |
| What are P- waves? | Quicker than S waves Longitudinal (compressions and rarefractions) vibrations in direction Solids and liquids |
| What are S-waves | Slower than P-waves Transverse - perpendicular to the direction of travel Only through solids |
| What happens when S- waves reach the liquid core? | They are reflected as they can't go through |
| What happens to P-waves as they enter the liquid core? | Their speed changes and are refracted due to the change in density. This is why we know there is a solid inner core as they are again refracted. |
| What is the wavelength? What is the amplitude? | Distance from crest to crest/ trough to trough/ rest to rest Distance from rest to crest or trough |
| What do waves transfer? | Energy, NOT MATTER |
| What is radiation? | A transfer of energy - not matter |
| What is the electromagnetic spectrum? | Radiowaves Microwaves Infrared Visible Light Ultraviolet X-ray Gamma Rays |
| What is a photon? | A packet of energy |
| What happens to radiation as you go through the spectrum? | Radio waves have the lowest frequency and biggest wavelength Gamma rays have the highest frequency and smallest wavelength |
| What is something called that emits radiation? | A source |
| What happens to thermal radiation as you increase the temperature? | The frequency increases |
| What speed does radiation travel? | The speed of light 3 X 10^8 m/s |
| What can happen to radiation once it has left the source? | Transmitted - go through e.g. glass Reflected - bounce back e.g. mirror Absorbed - taken in e.g. sunbather Multiple of these can occur at one e.g. windows reflect adn transmit |
| What is intensity? | How much energy arrives at each square meter of surface per second watts per square meter |
| What happens to intensity as distance increases? | It decreases as photons spread out so less hit the detector. Also, some may be absorbed or reflected on the way. |
| What is ionisation? | When a photon hits an atom or molecule, it sometimes has enough energy to remove an electron, changing the atom or molecule. |
| What are the 3 types of ionising radiation and why are they ionising? | Ultraviolet X-ray Gamma Ray A lot of energy is needed to do this and these have the highest energy |
| What can this do to your cells? | Can damage DNA which causes mutations. This is cancer. They can kill cells altogether. This is radiation poisoning. The longer the exposure, the more damage it causes. |
| How do X-rays work? | They are transmitted through less dense materials but absorbed by more dense materials. The varying amounts of radiation absorbed produces an image. |
| How are people protected from any potential X-ray dangers? | Radiographers stand behind concrete or wear lead aprons. Lead shields are put around areas that aren't being x-rayed. This protects people from any unnecessary exposure that could cause damage. |
| How can people be protected from UV rays? | Wear clothing to cover up Use suncream Stay inside at hottest times |
| What radiation can cause heating? | Infra-red and microwaves |
| How do microwave ovens work? | They're strongly absorbed by water molecules and make them vibrate, causing them to heat. Most food contains water. The higher the power, the quicker it heats the food. |
| What would they do to body cells and how is this risk prevented? | Heat up the water in them. Metal casing and screens on the doors reflect the radiation to stop it getting out. |
| How are microwaves used in mobile phones? | Emitted by them and carry the signal when making a call. Also, are emitted by phone masts. |
| What are perceived risks of using mobile phones? | Microwaves can heat body tissue which is believed to be caused cancer. However, the intensity is low and nothing to worry about. There is no evidence for any risk. |
| What radiation can pass through the atmosphere easily? | Radio waves and visible light |
| What are the greenhouse gasses and what do they do? | Water, Methane, Water Vapour Absorb radiation and re-radiate it in all directions, often back toward Earth |
| What is the greenhosue effect? | The Earth absorbs radiation from the sun, warming us up. The Earth emits some back to space, cooling us down. It's a lower frequency than that of the sun as Earth's cooler. The greenhouse gasses do their job. The atmosphere acts as an insulating layer. |
| What is ozone? | O3, a layer that absorbs UV radiation. Without it, a lot more UV would reach us which is ionising so can harm us. |
| How is it formed? | When an ozone molecule absorbs UV radiation, it splits into O2 and O. The O reacts with another O2 to make O3 again. Therefore the reaction is reversible. |
| What inputs carbon dioxide into the atmosphere? | Combustion of fossil fuels Respiration of plants and animals Respiration from decomposers |
| What removes carbon dioxide from the atmosphere in the carbon cycle? | Photosynthesis |
| The carbon cycle has been balanced for thousands of years. How are humans upsetting this? | Using more energy, e.g. for electricity or fuel in cars. This burns fossil fuels which produces a lot of carbon dioxide Population is rising therefore more space is needed for living and food. Deforestation to do this increases carbon dioxide through combustion/ reduces amount taken out. |
| What is a climate model? | Equations that mimic what is going on in the real climate taking into account information from various parts of the climate sytem |
| What does the climate model show? | Explains why the climate is changing now. We know it varies naturally, but recent changes cannot be explained naturally. Therefore it's due to human activity. |
| What are the consequences of global warming? | Rising sea levels - flooding Ice melts Changing weather patterns Heat = more storms and floods Impacts on food production |
| How is a) infrared b) radio waves c) microwaves Radiation used in communication? | a) TV controls/ night vision/ optical fibres b) TV & radio transmissions/ radar c) Mobile phones and satellite communication |
| Why are radiowaves adn microwaves good at transmitting information over long distances? | They don't get absorbed easily by the atmosphere due to their large wavelength. |
| What is the difference in communicating wavelengths compared to normal radiowaves and microwaves? | Radio waves for TV and radio are much shorter than normal Microwaves for mobiles are much longer than normal - but still tiny compared to radio waves. |
| How do satellites work? | Transmitter transmitted into space Absorbed by satellite receiver dish Transmits signal back to Earth Received by satellite dish on ground Reflects microwaves to reach a focal point - receiver. |
| How do optical fibres work? | Infrared or visible light bounces off the sides of a thin inner core of glass or plastic. The wave enters one end and keeps reflecting until it comes out the other. Light and infrared work well as they don't weaken too much and the glass doesn't absorb much |
| How is information transmitted? | Superimposed onto carrier EM waves ir sent long distance down telephone wires |
| What is the difference between analogue and digital? | Digital only has 2 values. Analogue has any value in a particular range |
| What happens to signals on their way and how is this overcome? | They weaken and collect noise. They are amplified to keep them able to be transmitted and digital signals are more often used to reduce noise. Amplifying analogue signals just amplifies noise too |
| Why are digital signals better than analogue? | Noise can be removed easier More information (bytes) can be sent at once Digital signals higher quality Easier to process due to computers being digital |
| What is power? | The rate of energy transfer |
| What does it mean to have 'high power'? | It transfers a lot of energy in a short space of time |
| What is efficiency? | How much % of the energy supplied is actually used for its intended purpose |
| What does a Sankey Diagram show? | How much energy is usefully used and how much is being wasted and in what from the output |
| Where is energy lost in a power station? | Through heat and sound |
| Why do we need to reduce the amount of energy we use? | Mainly comes from fossil fuels, which is a finite source and also pollutes a lot. Reducing energy means we reduce fuels needed to be burned so there's less pollution |
| How can we save energy at home? | Stop heat escaping- Cavity walls and loft insulation, double glazing and draught-proofing. Thick curtains/ fiberglass wool hot water tank jacket Reduce energy used - efficient appliances/ energy saving bulbs/ wash at lower temperatures/ turn down heating |
| What is cost effective? What is payback time? | How good something is for how much it costs How long it takes for he money saved to match the initial costs |
| How can energy be saved in the workplace? | Using less paper Incentives for energy efficient travel to work e.g. cycling/ public transport |
| How can the government encourage energy saving? | Offer grants for better home insulation Trade in old boilers for more efficient ones More public transport Investing in alternative energy sources Improving recycling services Making laws to ensure new housing and businesses are energy efficient |
| What does renewable mean? Why do we need to use renewable sources? | A source will never run out or can be easily replenished Non- renewable resources will run out and currently provide most of our energy. They damage the environment less |
| What's a problem with renewable energy? | They don't provide as much energy and are often unreliable depending on the weather. Some cannot increase supply to meet high demand |
| How do primary resources work in power stations? | Energy is released from the fuel (burning or splitting of atoms) and generates steam. The steam turns a turbine. A generator turns the kinetic energy from the turbine into electricity |
| How can fossil fuels harm the environment? | Release a lot of carbon dioxide, resulting in global warming Coal and oil release sulfur dioxide, causing acid rain Coal mining makes a mess of landscape Oil spillages damage wildlife |
| Why do we use fossil fuels? | They produce lost of energy, are relatively cheap and don't rely on weather so can meet high demand. There are already lots of power stations so more don't have to be built, saving money. |
| How does a nuclear power station work? | Fission releases energy This heats water to make steam Turns a turbine Generator converts this into electricity |
| What are the advantages of this? | Lots more energy than combustion Doesn't produce carbon dioxide The fuel (uranium/plutonium) is relatively cheap |
| What are the disadvantages? | Radioactive waste - stays for long time Extra safety precautions needed e.g. test workers/ waste disposal/ contamination of land People near may oppose High set up and decommissioning costs Longest time to start up Ionising radiation - kill/damage cells |
| What is the difference between contamination and irradiation? | Irradiation is being exposed to radiation without coming into contact with the source. You stop being exposed as soon as you leave. Contamination is picking up radiation so you're still exposed for a long time. |
| How does wind power work? | Turbines put in exposed places e.g. moors/coast Wind turns turbine which directly turns a generator inside each turbine Energy is generated directly from the wind |
| What are the advantages? | No CO2 is produced during use Is renewable No running costs and minimal running costs No permanent damage to landscape if removed |
| What are the disadvantages? | Noisy Spoil the view High set up costs Don't produce much energy Can't increase supply with demand Unreliable e.g. if not windy |
| How do solar cells work? | They generate electric currents directly from the sunlight. Often used in remote places and on a small scale |
| What are the advantages? | They have no fuel costs and running costs Renewable Don't produce CO2 Cost - effective even in cloudy countries Good for small scale |
| What are the disadvantages? | High set up costs Not cost-effective or practical to join to National Grid A lot of energy in manufacture |
| How does wave power work? | Small wave-powered turbines located around the coast. As waves come in, their up/ down motion spins a turbine which drives a generator. Good on small islands but not a huge scale. |
| What are the advantages? | Renewable No pollution No fuel costs and minimal running costs |
| What are the disadvantages? | Hazard for boats Spoil the view High set up costs Unreliable - wind drop = wave drop |
| How do tidal barrages work? | Dams are built across river estuaries with turbines in them. As the tide comes in, it fills the estuary to a height of several meters and spins the turbines. The water is allowed through the turbines at a controlled rate. The source is the gravity fo sun and moon controlling tides |
| What are the advantages? | Renewable Reliable - always at least 2 tides a day No fuel costs and minimal running costs Potential to generate significant amount of energy |
| What are the disadvantages? | Prevents access by boats Ruins view Alters wildlife habitat High initial costs Variable height tide means sometimes less energy is produced |
| How do biofuels work? | Burned to produce energy in thermal power stations. Can also be used in cars. Solids, (straw/ woodchips) liquids (ethanol) and gasses (methane biogas) |
| What are the advantages? | They are carbon neutral Renewable Quick to access |
| What are the disadvantages? | Forest has been cleared to make room for these. Therefore animal lose habitat and CO2 added to atmosphere from the decay and burning. Room for this could be used for other things, like growing crops |
| What is geothermal energy? | Water is piped down into hot rocks. It boils and becomes steam which turns a turbine and a generator turns this into electrical energy. |
| What are the advantages? | Free Renewable energy No real environmental problems |
| What are the disadvantages? | Costly to drill several km down to reach the hot rock so not many places where this is economically viable |
| What is hydroelectricity? | Flooding a valley by building a big dam. This collects rainwater which is allowed out through turbines, driving them directly to drive generators to produce electricity. Located in remote values to reduce human impact |
| What are the advantages? | Immediate response to increased demand No fuel and minimal running costs No pollution (as such) Reliable - except in drought |
| What are the disadvantages? | Flooding valley causes animals to lose habitat Rotting vegetation releases methane and CO2 High initial costs |
| Why do we need to use a mix of energy sources? | Renewable resources struggle to produce the same output as fossil fuels We're dependent on other countries for fossil fuels Fossil fuels are finite/ major pollutants Renewable resources are variable |
| What do we need to consider when deciding what energy source to use? | Economics (cost) Environmental impact |
| What do we consider with economics? | Running costs - renewables have lowest because no fuel needed. Set up costs - Renewables often need more for the same output so costs more Nuclear reactors, hydroelectric dams and geothermal power stations need lost of engineering |
| What do we consider with environmental impact? | Different types of pollution in the book e.g. light/ waste and air/ noise/ view/ habitat destruction/ resources/ carbon dioxide/ leisure activity disruption |
| How does a generator work? | The turbine rotates a magnet in a coil of wire. The turning magnet causes the magnetic field through the coil to change, inducing a voltage and making a current flow in the coil. The kinetic energy from turbines it turned into electrical energy. |
| What is electromagnetic induction? | Moving a magnet in a coil of wire causes them magnetic field through the coil to change. This induces a voltage and if this is part of a complete circuit, a current will flow. |
| How can you increase the voltage and current in the wire? What does this mean in terms of energy? | Turn the magnet - therefore the turbine - faster. This means more primary resources are used to produce more energy to turn it quicker so more finite resources are used. |
| What is the National Grid? | Network of pylons and cables over Britain that takes electrical from power stations to where it's needed in homes and industry. Power can be generated anywhere on the grid and supplied to anywhere else on the grid |
| Why is high voltage used instead of high current? | Lots of energy is lost through heat with high current. The voltage is much more efficient and cheaper. It reduces energy loss. |
| What happens to voltage before it reaches our homes? | It is reduced to 230 v - the mains supply. |
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