Physics - Paper 1

• Evaluate


  Give both sides of the question, offer some comparison and try to add value
• If given a table with data, don't just quote values, also write a conclusion
• All evaluate questions in AQA GCSE Science have one common Mark scheme and without giving a strongly Justified conclusion you can't get into the top level
• Writing a method


  1. Give a logical flow, in the form of a numbered list of instructions

  2. Have a reader check if the method makes sense
• Working scientifically skills assessed

  • Identifying variables
  • Knowing the difference between repeatable and reproducible
  • Knowing that resolution is the smallest difference in results that can be identified
  • Knowing that computerized methods are more accurate, rapid and sensitive
  • Knowing that line of best fit does not need to be straight
• Systematic error


  Caused by poorly calibrated equipment, can be solved by adjusting calculations
• Random error


  Caused by equipment not being sufficiently precise or natural fluctuations in the true value
• The way to account for errors is to make multiple readings and calculate a mean
• 20% of the marks in GCC science papers are for math skills, and in physics papers it's 30%
• Units that can be assessed

  • Milli (1/1000)
  • Micro (1/1,000,000)
  • Nano (1/1,000,000,000)
  • Kilo (1000)
  • Mega (1,000,000)
  • Giga (1,000,000,000)
  • Centimeters (100 per meter)
• The equation sheet doesn't tell you the units for the quantities, and only gives one version of each equation
• Units for quantities


  • Energy/Work - Joules
  • Speed - Meters per second
  • Mass - Kilograms
  • Height - Meters
  • Power - Watts
  • Time - Seconds
  • Charge - Coulombs
  • Potential Difference - Volts
  • Current - Amps
  • Resistance - Ohms
  • Density - Kilograms per meter cubed
• System


  An object or group of objects
• Ways energy can be stored in a system

  • Magnetic
  • Kinetic (moving object)
  • Thermal (hot object)
  • Gravitational potential
  • Chemical (bonds)
  • Elastic potential (stretched object)
  • Electrostatic
  • Nuclear
• Energy transfer


  Can happen by heating, mechanically, electrically, or by radiation
• Conservation of energy


  In a closed system, energy cannot be created or destroyed, only transferred between stores
• Calculating gravitational potential energy


  1. Write down the equation

  2. Substitute the values (mass, gravitational field strength, height)

  3. Calculate the answer and include the units (Joules)
• Calculating kinetic energy


  1. Write down the equation

  2. Substitute the values (mass, velocity)

  3. Calculate the answer and include the units (Joules)
• Calculating elastic potential energy

  1. Write down the equation

  2. Substitute the values (spring constant, extension)

  3. Calculate the answer and include the units (Joules)
• Specific heat capacity


  The maximum amount of energy a substance will absorb to change its temperature by 1 degree C per 1 kilogram
• Calculating specific heat capacity

  1. Use the equation: change in energy = mass x specific heat capacity x change in temperature

  2. Rearrange to solve for specific heat capacity if needed
• The required practical is to find the specific heat capacity of a metal block or liquid
• Change in temperature


  Difference between starting and ending temperature
• Mass


  Must be in kilograms (if given in grams, divide by 1000)
• Specific heat capacity


  How much energy it takes to heat up 1 kg by 1 degree C
• Required practical to find specific heat capacity


  1. Given metal block or container of liquid

  2. Use balance to measure mass

  3. Insulate to minimise energy losses

  4. Use thermometer to measure temperature change

  5. Use electrical heater to heat up

  6. Calculate energy transferred using voltmeter, ammeter and stopwatch
• Power


  Rate at which energy is transferred or work is done
• More powerful appliance


  Faster it can do work or transfer energy
• Calculating power


  Energy (in joules) divided by time (in seconds)
• Efficiency


  Proportion of energy that has been usefully transferred, can be expressed as decimal or percentage
• Conservation of energy - same amount of energy at end as start, but some transferred wastefully
• Ways to reduce wasted energy

  • Reduce heat loss by insulating
  • Reduce drag by streamlining
  • Reduce friction
• Energy resources


  • Renewable (generated faster than used)
  • Non-renewable (finite, used faster than generated)
• Factors to consider for energy resources

  • Renewability
  • Cost
  • CO2 emissions
  • Reliability
  • Geographic restrictions
  • Radioactive waste and risks (for nuclear)
• Need to know all circuit symbols and be able to draw circuits properly
• Equations may require multiple steps to solve, even if equation sheet provided
• Current


  Speed of flow of charge around circuit
• Potential difference


  Amount of energy being transferred by a component
• Required practical 15 - Measure IV characteristics

  1. Use ammeter in series, voltmeter in parallel

  2. Calculate resistance using R=V/I

  3. Investigate wires of different lengths and resistors in series/parallel
• Required practical 16 - Investigate IV characteristics

  1. Use ammeter in series, voltmeter in parallel

  2. Swap out different circuit components and draw IV graphs