P1

• Energy store


  The capacity for doing work
• Types of energy store

  • Magnetic
  • Internal (thermal)
  • Chemical
  • Kinetic
  • Electrostatic
  • Elastic potential
  • Gravitational potential
  • Nuclear
• Magnetic energy store


  • The energy stored when repelling poles have been pushed closer together or when attracting poles have been pulled further apart
• Internal (thermal) energy store

  • The total kinetic and potential energy of the particles in an object, in most cases this is the vibrations - also known as the kinetic energy - of particles. In hotter objects, the particles have more internal energy and vibrate faster
• Chemical energy store


  • The energy stored in chemical bonds, such as those between molecules
• Kinetic energy store

  • The energy of a moving object
• Electrostatic energy store


  • The energy stored when repelling charges have been moved closer together or when attracting charges have been pulled further apart
• Elastic potential energy store


  • The energy stored when an object is stretched or squashed
• Gravitational potential energy store


  • The energy of an object at height
• Nuclear energy store


  • The energy stored in the nucleus of an atom
• Energy


  The capacity for doing work
• Energy can remain in the same store for millions of years or sometimes just for a fraction of a second
• There are energy transfers going on all the time - whenever a system changes there is a change in the way some or all of the energy is stored
• Energy transfer


  When something is moved from one place to another. This may be people, objects or energy.
• Types of energy transfer

  • Mechanical work - a force moving an object through a distance
  • Electrical work - charges moving due to a potential difference
  • Heating - due to temperature difference caused electrically or by chemical reaction
  • Radiation - energy transferred as a wave, e.g. light and infrared
• Doing 'work' is the scientific way of saying that energy has been transferred
• Energy store


  The different ways in which energy can be stored, including chemical, kinetic, gravitational potential, elastic potential and thermal stores
• Energy transfer


  The different ways in which energy can be transferred from one store to another includes heating, by waves, electric current or by a force moving an object
• Energy store


  The capacity for doing work
• Energy


  • Cannot be created or destroyed
  • Can be transferred, dissipated or stored in different ways
• Energy dissipation


  The spreading out and transfer of energy stores into less useful forms, such as thermal energy causing the surroundings to heat up
• Dissipated energy is often referred to as 'wasted' energy, since it is not transferred to a useful output
• Electrical cables warming up


  • Energy is dissipated to the surrounding air
• Two surfaces rubbing together

  • Work is done against friction which causes heating of the two surfaces - so the internal (thermal) energy of the surfaces increases
• Lubricant


  Reduces the friction between two surfaces
• Using LED light bulbs as opposed to filament lamps


  • Causes less energy to be wasted
• Electrical work


  Energy transferred by an electric current
• No system is perfect. Whenever there is a change in a system, energy is transferred and some of that energy is dissipated
• Energy store


  The capacity for doing work
• Energy


  • Cannot be created or destroyed
  • Can be transferred, dissipated or stored in different ways
• Energy dissipation


  1. Spreading out and transfer of energy stores into less useful forms, such as thermal energy causing the surroundings to heat up

  2. Dissipated energy is often referred to as 'wasted' energy, since it is not transferred to a useful output
• When there is a change in a system

  Energy is transferred and some of that energy is dissipated
• Energy dissipation


  • Electrical cables warming up
  • Two surfaces rubbing together causing heating
  • Filament lamps dissipating energy as heat compared to LED light bulbs
• Friction


  A force that opposes or prevents movement and converts kinetic energy into heat
• Lubricant


  Anything which reduces the friction between two surfaces
• Electrical work


  Energy transferred by an electric current
• No system is perfect
• Any energy that is not transferred to useful energy stores is said to be wasted because it is lost to the surroundings
• Work


  When energy is transferred to an object
• Power


  The rate at which energy is transferred