GCSE physics

• Energy can never be created or destroyed, it can only be transformed from one form to another
• Types of energy stores

  • Magnetic
  • Internal
  • Chemical
  • Kinetic
  • Electrostatic
  • Elastic potential
  • Gravitational potential
  • Nuclear
• Monomers

  Smaller units from which larger molecules are made
• Polymers

  Molecules made from a large number of monomers joined together in a chain
• Synthetic polymers

  • nylon
  • polyethylene
  • polyester
  • Teflon
  • epoxy
• Enzymes

  • They increase the rate of chemical reactions without themselves being consumed or permanently altered by the reaction
  • They increase reaction rates without altering the chemical equilibrium between reactants and products
• As temperature increases


  The rate of reaction increases
• Kinetic energy


  Energy of motion, calculated as 1/2 * mass * velocity^2
• Doubling the mass of an object doubles its kinetic energy, but doubling the velocity quadruples its kinetic energy
• Elastic potential energy

  Energy stored in a stretched or compressed spring, calculated as 1/2 * spring constant * extension^2
• Gravitational potential energy

  Energy an object has due to its position in a gravitational field, calculated as mass * gravitational field strength * height
• Specific heat capacity

  The energy required to change the temperature of 1 kg of a substance by 1°C
• Measuring the specific heat capacity of an aluminium block

  1. Set up apparatus with heater, voltmeter, ammeter

  2. Record voltage and current every 60 seconds

  3. Calculate energy transferred using I*V*t

  4. Plot temperature vs energy graph

  5. Specific heat capacity = 1/mass * gradient of line
• Power

  The rate of energy transfer, measured in watts (J/s)
• Energy efficiency

  Useful energy out / total energy in, expressed as a percentage
• In a closed system, the total energy remains constant
• Thermal conductivity

  How easily heat can flow through a material
• Investigating the effectiveness of different insulating materials

  1. Use equal amounts of hot water in beakers with different insulation materials

  2. Measure temperature change over time

  3. Best insulator has smallest temperature drop
• Investigating factors affecting thermal insulation properties

  1. Use same insulation material but vary thickness in different beakers

  2. Measure temperature change over time

  3. Thicker insulation has smaller temperature drop
• Investigating factors affecting thermal insulation properties of a material

  1. Use 5 beakers with different thicknesses of the same insulation material

  2. Put equal amounts of hot water in each beaker

  3. Record temperature every minute as it drops

  4. Beaker with most insulation layers will have smallest temperature drop
• Types of energy resources

  • Non-renewable (coal, oil, natural gas, nuclear)
  • Renewable (solar, wind, geothermal, hydroelectric, tidal, biomass, wave)
• Fossil fuel power stations

  • Burn fossil fuels to heat water, steam turns turbines connected to generator to produce electricity
• Advantages of fossil fuels

  • Reliable energy production
  • Fuels easily transported
• Disadvantages of fossil fuels

  • Non-renewable
  • Release greenhouse gases contributing to global warming
  • Release pollutants like nitrogen oxides and sulfur dioxides
• Greenhouse gases from fossil fuels

  Trap heat, causing global warming
• Wind power

  • Converts kinetic energy into electrical energy using turbines
  • Advantages: renewable, low cost, no emissions
  • Disadvantages: unreliable, limited locations, visual impact, can kill birds
• Solar energy

  • Uses solar cells to convert light energy into electrical energy
  • Advantages: renewable, low maintenance, no emissions
  • Disadvantages: unreliable, limited locations, large surface area required
• Hydroelectric power

  • Uses gravitational potential energy of water flowing through turbines to generate electricity
  • Advantages: renewable, low maintenance, no emissions
  • Disadvantages: risk of dam failure, habitat destruction, limited locations
• Biomass energy

  • Burning plant and animal waste to produce heat and electricity
  • Advantages: renewable, cheap fuel, takes in CO2 when growing
  • Disadvantages: releases CO2, can limit biodiversity, moral issues with using food crops
• Nuclear energy

  • Energy from nuclear fission reactions
  • Advantages: high energy density, no emissions
  • Disadvantages: risk of disasters, expensive decommissioning, radioactive waste disposal
• Geothermal energy

  • Uses heat from the Earth's interior to heat water and generate steam to turn turbines
  • Advantages: renewable, low maintenance, no emissions
  • Disadvantages: limited locations, can trigger earthquakes, potential greenhouse gas release
• Wave energy

  • Uses motion of waves to turn turbines and generate electricity
  • Advantages: renewable, low cost, no emissions
  • Disadvantages: limited locations, high initial cost, can disrupt marine life and shipping
• Tidal energy

  • Uses tidal movements to turn underwater turbines and generate electricity
  • Advantages: reliable, renewable, minimal wildlife disruption
  • Disadvantages: limited energy output, high initial cost, can disrupt marine life
• Static electricity

  Charge transfer between insulating materials when rubbed together
• Charged balloon

  Sticks to wall due to attraction between balloon's charge and wall's induced charge
• Use of static electricity

  Efficient car painting by charging car and paint oppositely
• Cloud full of electrons

  Causes electric shock/lightning when discharging to ground
• Electric field

  Region in space where charged particles experience a force
• Uniform electric field

  • Field lines are evenly spaced
• Radial electric field

  • Field lines are denser closer to the source