systematic errors

• What should you be able to describe by the end of this video?

  Systematic error and zero error
• What aspect of the GCSE specification does this topic belong to?

  Working scientifically
• What percentage of marks in exams does working scientifically represent?

  At least 15%
• What is an accurate measurement?

  A measurement close to the true value
• What do random errors lead to in measurements?

  Random variations
• What is one cause of random errors in measurements?

  Using equipment incorrectly
• How can random errors be reduced?

  By taking more measurements and recalculating a mean
• What is systematic error?

  Results differ from the true value consistently
• In the magnesium and acid experiment, what caused the systematic error in repeat three?

  Different conditions compared to repeats one and two
• What could explain the lower temperature readings in repeat three?

  Using a lower concentration of acid
• What is a zero error?

  When equipment gives a non-zero reading when it should be zero
• What would thermometer B read in iced water if it has a zero error?

  -10° C
• How does a zero error affect temperature readings?

  All readings are lower than the true temperature
• What should students do if they suspect a systematic error?

  Repeat the experiment with different equipment
• If a thermometer reads 10° C lower than the true value, how can students adjust their readings?

  Add 10° C to each reading
• What are the differences between random errors and systematic errors?

  • Random errors:
  • Lead to random variations
  • Cannot be eliminated, only reduced
  • Systematic errors:
  • Consistent difference from true value
  • Require a new experiment to correct
• What steps should students take if they suspect a zero error in their thermometer?

  1. Identify the zero error amount
  2. Adjust readings by adding the error
  3. Consider repeating the experiment with accurate equipment