percentage uncertanties

• how do you calculate percentage uncertainty

  divide the uncertainty by the measured quantity, and multiply the result by 100
• for measurements that require 2 readings (e.g. change in temperature) 


  uncertainty = 2 x uncertainty of each reading
• The resolution of an instrument is the smallest difference between its graduations or readings
• uncertainty = resolution/2
• Which measurements require two readings

  • Change in temperature
  • Change in volume
  • Mass
  • Length
• Chemists may reduce percentage uncertainty by increasing the quantities they measure