Physics paper 1 Energy

• Reducing unwanted energy transfers

  1. Using thermal insulation

  2. Using lubrication
• The idea in this video isn't to memorize everything but to understand the principles so that you could suggest how to reduce energy loss in a particular exam question
• Typical house


  • People like their home to be nice and warm even if it's freezing cold outside
  • Need to reduce the amount of heat energy that escapes to the outside environment
• Reducing heat loss in a house

  1. Make the house sealed closed to prevent air passing out

  2. Reduce heat loss by conduction through walls and windows

  3. Fill air gaps with insulating foam to prevent convection and conduction
• Conduction


  Heat is lost directly through a solid like a wall or a window
• Convection


  Heat is transferred through liquids and gases
• Insulation in houses


  • Cavity walls with air gap filled with insulating foam
  • Double glazing with air gap between panes of glass
• Friction


  Resistance that an object encounters when moving over a solid or through a fluid
• Friction


  Reduces the efficiency of energy transfer and can cause objects to heat up
• Reducing friction


  1. Adding oil (lubricant) to reduce friction

  2. Making cars and planes streamlined to reduce air resistance
• Series circuit


  A circuit with no branches, where the current can only flow in one path around the circuit
• Electric current


  The flow of electrical charge around a circuit
• Electric current


  • It is never used up in a circuit
  • In a series circuit, the current is the same all the way around
• Circuit components


  • Cell
  • Lamp
  • Open switch
  • Closed switch
• Ammeter


  A device used to measure the electric current in a circuit
• The unit of electric current is the ampere (A)
• The term "amp" is an acceptable short form of "ampere"
• Scientists used to think current flowed from positive to negative, but now know it flows from negative to positive</b>
• The direction of current flow is still represented as flowing from positive to negative
• Renewable energy resource


  One that is being or can be replenished as it's used
• Renewable energy resources


  • Wind power
  • Solar power
  • Hydroelectric power
  • Tidal power
  • Biofuels
  • Geothermal
• Advantages of renewable energy resources

  • They'll never run out
  • They do not add any carbon dioxide to the atmosphere
• Disadvantages of renewable energy resources

  • Wind power and solar power are not reliable
  • Hydroelectric power destroys habitats and is only useful in countries with lots of rivers
  • Tidal power has potential but is not currently used in the UK
  • Wave power is small-scale and experimental
  • Geothermal energy is not used much in the UK
  • Most energy use in the UK is for transport which renewable resources cannot easily power
• Biofuels


  Produced from plant materials, carbon neutral as the growing plant took in carbon dioxide
• Biofuels can be used to power vehicles such as cars and buses
• Using land to grow crops for biofuel could push up the price of food
• Current = Charge / Time
• The current through an object depends on the resistance, potential difference and charge
• Electricity is the flow of charge
• Potential Difference (V) = Current (A) x Resistance (Ω)
• Resistors have different resistances depending on their material and shape
• Series circuits - all components connected end to end
• Series circuits are connected end-to-end with only one pathway for electricity to travel around
• Charged particles are called ions or electrons
• Parallel circuits - components are connected side by side with separate paths from positive to negative terminals
• Parallel circuits split into two or more paths so that there's more than one way for electrons to move around the circuit
• In series circuits, if any component breaks down then no current will be able to pass through it
• In series circuits, if one component breaks then no electricity flows at all
• In parallel circuits, if one component breaks it doesn't affect the rest of the circuit
• In series circuits, if any component breaks or has high resistance then it will affect the whole circuit