| Statement | Response | Comment |
| Energy cannot be created or destroyed but it can be . . . | transferred from one form to another. | For example: electricity into light. |
| When different parts of a substance are at different temperatures, energy is transferred from . . . | high temperature to lower temperature. | Heat flows from HOT to COLD (unless you are inside a fridge!) |
| When heat is transferred between solids the process is called . . . | Conduction | Vibrating atoms transfer kinetic energy - but free electrons in metals make them better conductors than non-metals. |
| Liquids and gases can flow and so can transfer energy by . . . | Convection | Hot fluid rises and is replaced by cooler fluid which sinks. |
| Energy can travel through a vacuum by . . . | RADIATION | How do you think sunlight reaches the Earth? |
| Hot bodies emit . . . | INFRA-RED radiation. | The hotter the body, the shorter the wavelength of radiation emitted. |
| Dark, matt (dull) surfaces are good . . . | absorbers AND emitters of radiation. | If HOT it emits - if COLD it absorbs. |
| Light, shiny surfaces are good . . . | reflectors but poor absorbers or radiation. | Shiny surfaces are also poor emitters - they keep heat in. |
| If you want to insulate your house you could . . . | double glaze windows, fill cavity walls, insulate the loft with fibre glass. | All these methods are used and more. Can you think of any? |
| When energy is transferred only some it of is useful, the rest is transferred in some non-useful way, usually as . . . | heat, which is wasted. | We are heating up the Earth with our waste energy. |
| The result of 'wasted' energy is that . . . | the surroundings become warmer. | This can be put to good use to heat homes - but it needs careful planning. |
| Energy lost from a system becomes increasingly spread out and it is therefore . . . | difficult to use for further energy transfers. | Low grade heat is not useful because the temperature difference is small. |
| If a device uses a high percentage of the energy supplied in a useful way we say it is . . . | more EFFICIENT. | NOTHING is ever 100% efficient! |
| The efficiency of a device is calculated by finding the ratio . . . | Useful energy transferred/total energy supplied | Usually less than 90% |
| Renewable energy resources are ones which can be . . . | used over and over and will never run out. | At least not within the expected lifetime of the Sun. |
| Non-renewable resources are ones which . . . | are finite and which cannot be replaced during the lifetime of a human. | Long term projects could regenerate some of our fuel supplies but not without significant cost. |
| Fossil fuels are those which . . . | formed over millions of years deep inside the Earth. | They are not going to be replaced - ever! |
| Coal, oil and natural gas are all examples of . . . | Non-renewable resources - they are fossil fuels. | The conditions which created them are unlikely to occur again on this planet. |
| Wind, wave, tidal, geothermal and solar energy are examples of . . . | renewable resources. They depend on the energy stored in the Earth, Sun and Moon and will last as long as they do. | The sun has over 5 billion years to live - we hope! |
| Most of the energy presently used by humans comes from non-renewable resources. We need to save them because . . . | the more economical we are, the longer they will last. | Until we find alternatives. |
| It is important to find alternative resources because . . . | one day the fossil fuels will run out. | We depend on oil for most of our transport. |
| Wood from trees is a renewable energy resource providing that . . . | we replant at least as many trees as we cut down. | The Amazon basin is being deforested at an alarming rate ! |
| Electricity is a convenient, widely used energy source because . . . | it can easily be transferred into other forms of energy. | Think how many devices in your home use electricity. |
| In most power stations, energy from fuel is used to . . . | heat water to produce steam. | High pressure steam is used to drive turbines which are connected to generators. |
| Nuclear power stations use nuclear fuel, mainly . . . | uranium and plutonium | They also produce heat to make steam. |
| Renewable energy resources can also be used to produce electricity. These include . . . | wind, waves, hydro-electric and geothermal energy. | The technology needed is quite advanced in most cases. |
| Geothermal energy comes from . . . | the decay of radioactive elements in Earth's crust which release heat. | In volcanic areas hot water and steam rise to the surface and can be tapped. |
| Electricity can be produced directly from the Sun's radiation using . . . | solar cells | Passive solar heating can also be used to heat homes and offices. |
| Burning fossil fuels releases a gas called . . . | carbon dioxide and also sulphur dioxide. | Both bad for the planet. |
| The presence of CO2 in the Earth's atmosphere leads to . . . | the Greenhouse effect | Heat from the Sun is trapped and cannot escape to space. |
| The presence of SO2 in gases emitted by power stations causes . . . | acid rain which destroys trees. | The sulphur dioxide can be removed from the waste gases but this increases the cost of the electricity. |
| Nuclear power stations do not produce harmful gases. The main risk is from . . . | the possible escape of radiation in the event of an accident. | Chernobyl in 1987 was a serious accident which affected all of Europe. |
| The main disadvantage of nuclear power is . . . | the radioactive waste which must be stored for thousands of years. | No one wants it in their backyard. |
| Wind power is being developed in the UK. What are the main drawbacks? | We need thousands of wind turbines and they look unsightly in the countryside. | Also they need wind, which isn't always there when you need it. |
| A tidal barrage across a river estuary can produce a lot of energy. Why don't we have lots of them? | They are costly and destroy wildlife. | There are not that many suitable rivers actually. |
| Hydroelectricity is a good way of producing cheap electricity. What are the drawbacks? | You need suitably high mountain reservoirs and they change the landscape permanently. | Whole villages have been flooded by damming rivers. |
| Why are coal-fired power stations running all the time? | It takes too long to start and stop them. | We need to top-up our electricity supply at peak times using HEP and gas turbines. |
| The most expensive way to produce electricity at present is by . . . | solar cells. | They have a high cost per unit but are suitable for remote locations. |
| Energy is normally measured in . . . | joules | 1 J is the work done when a force of 1N moves through a distance of 1metre in the same direction as the force acts. |
| When a force acts on an object, the work done is equal to . . . | the energy transferred | W = F x s |
| Work done by a force = | force x distance moved in the direction of the force | 1N x 1m = 1J |
| The rate at which energy is transferred is . . . | power | in joules per second |
| The unit of power is the . . . | watt | 1W = 1J/s |
| Power = | work done / time taken | or work = power x time |
| The energy stored in an object which has been lifted against the force of gravity is . . . | gravitational potential energy | which depends on the height |
| Gravitational potential energy = | weight x change in vertical height | weight = mg |
| Weight = | mass x gravitational field strength | 9 = 10 N/kg |
| The gravitational field strength at the surface of the Earth is approximately . . . | 10 N / kg | g = 10 N/kg |
| A body falling freely in Earth's gravity will accelerate at . . . | 10 metres per second squared | g = 10 m/s^2 |
| The energy an object has because of its movement is called . . . | kinetic energy | energy of motion |
| Kinetic energy = | 1/2m v^2 | 1/2 mass x speed squared |
| When energy is transferred from one form to another the total amount of energy is . . . | conserved | This can be difficult to believe when friction is acting - friction produces heat |
| How much energy dya need 2 hav ur MUM | WEll | As much as i can get..girl goes on ALL NIGHT!!! |
