Paper 1 content

• What energy stores can be transported when two objects collide?

  all mechanical transfers (includes)

  
  

  -thermal

  -kinetic

  -gravitational

  -elastic (potential)
• The equation: "elastic potential energy = 1/2 x spring constant x extension2" only works if the spring has not exceeded its limit of proportionality
• The amount of energy a material releases depends on:

  -the specific heat capacity of that material

  -the mass of material that is cooling
• The higher the specific heat capacity of the substance, the more energy required to increase its temperature
• According to the law of transportation of energy:

  energy can be transferred usefully, stored or dissipated
• watt= joule per second
• conduction= the transfer of energy from one place to another without the movement of the particles

  vibrating particles transfer energy to neighbouring particles
• convection= the transfer of heat by the movement of hot and cold air

  energetic particles move away from hotter regions to cooler regions (and transfers energy in doing so)
• The higher the thermal conductivity, the higher the rate of energy transfer
• energy resources are used for: transport, electricity and heating
• Using geothermal energy as an energy resource:

  -renewable

  -reliable (rocks underground remain hot and continuously provide energy)

  -does minimal damage to the environment

  -can be used to generate electricity and directly heat homes
• What are the problems with using hydro-electric power?

  as it requires the flooding of a dam:

  it can destroy animal habitats

  can cause the release of greenhouse gases due to rotting vegetation (leads to global warming)
• burning of bio-fuels produce greenhouse gases, and also requires clearing land to grow these crops (which can destroy animal habitats)
• nuclear fuel as an energy resource produces dangerous nuclear waste that's difficult to dispose of, but also produces no greenhouse gases
• wave power produces no pollution, but turbines can disturb the seabed and disrupt animal habitats
• on impact, some kinetic energy will be transferred as sound energy
• when an object falls, energy is transferred away from the gravitational energy store
• modern energy demand has decreased over the years due to people trying to be more energy efficient

  government targets also put an increase on the UK's renewable energy resources by putting pressure on energy companies to build more power plants
• power is the rate in which energy is transferred/ rate of work being done
• energy waste can be reduced by:

  1)lubrication (oil in a motor- reduces friction so less heat energy)

  2)thermal insulation (e.g double glazing, less useful thermal energy is lost)
• what are biofuels?

  Renewable fuels made from organic matter, such as plants or animal waste.
• Why do hot air balloons rise?

  -The heat from the burners cause the air inside to become less dense --> less dense air will rise, like in a convection current.

  Because these particles are trapped it moved the balloon up with them
• thick walls --> conduction occurs slower

  
  

  low thermal conductivity --> rate of energy transfer is slower

  high thermal conductivity --> rate of energy transfer is faster

  
  

  thermal conductivity = the ability to move heat quickly and efficiently
• metals are good heat conductors as their particles are packed close together, and their delocalised electrons allow for the transportation of thermal energy throughout the structure
• fluids --> liquids and gases; fluids are substances that can flow
• Whilst swimming:

  It is more difficult to swim back to the (shallow) shore on a sunny day because --> the sun heats shallow water faster at the edge as to the deeper water. This creates a convection current that flows towards the centre.

  Since water is transparent the sun cannot heat it directly. Therefore it heads the bed of the lake where the water is shallow --> the warmth of this lake bed then transfers heat to the water, making it less dense.

  -As less dense water rises, a convection current is created that flows away from the shore
• thunderstorms --> created when large amounts of hot, moist air rises through the atmosphere. As the moist air rises it cools, and then this moisture condenses to form rain

  The size and speed of movement in this convection current created high winds and static electricity (lightning)
• filament lamps --> most energy is lost as heat; the filament is a resistance wire designed to become hot so that it emits energy in the visible light part of the spectrum
• What are 2 of the uses of infrared radiation?

  1)electrical heaters/ cooking food

  2) short-range communication (e.g. remote controls/ optical fibres)
• current --> flow of charge in a circuit
• conventional current --> positive to negative terminal
• charge --> the measure of the total current that flowed within a period of time
• system --> an object/ group of objects
• conduction:

  -energy is transferred by heat to kinetic energy stores

  -particles vibrate and transfer this kinetic energy to each other

  
  

  (this continues until energy is transferred to the whole block)
• friction --> energy is dissipated to thermal store
• What are two everyday used for fossil fuels?

  -electricity

  -gas

  -burning coal/ coal in steam trains
• step up transformer —> increased potential difference; decreases current

  this reduces thermal energy lost to surroundings, increasing the efficiency
• step down transformer —> decreases p.d (to a safer value)

  uses fewer turns in secondary than primary coil —> decreases voltage of AC electrical supply
• using lubrication:

  -less friction --> less work done against friction

  -higher efficiency, due to less work against friction, as less energy is lost as thermal energy
• area of an object --> can be worked out using a measuring cylinder and working out the initial volume of the water, then adding the object, and measuring the final volume

  Then using the equation: volume= final volume - initial volume