problem solving

• how to improve the reliability of an experiment?

  By repeating the experiment
• Why did they repeat the experiment?

  To make results more reliable
• Controls

  A control is when you take away the ‘active ingredient’ and replace it with something ‘null’ to check your experiment is happening for the reason you think it is
• Name a variable not already mentioned that you need to control in this experiment (it is almost always one of these)


  Temperature, pH, concentration, type of a solution, type of something (Which one hasn’t been controlled?)
• comparing experiments validity

  Compare the two experiments with everything in common except the factor you want to investigate. Change only one variable.
• percentage questions 


  number given divided by 100 multiplied by percentage given
• Percentage questions if calculating a score

  first number divided by what it’s out of multiplied by 100
• Ratio 


  _:_, remember to simplify