Obtaining, analysing and evaluating results – WJECRandom errors
Under the new GCSE specifications in Wales, practical work in Science will be examined. This unit will help students to prepare for the practical examination.
Random errors are errors made by the person carrying out the measuring, and are usually down to timing incorrectly, or reading the instrument incorrectly. It is important to try to reduce or limit the effect of random errors in measuring.
Reaction time errors and parallaxWhen something appears different when you look at it from different positions. errors are examples of random errors.
Figure caption,
Reaction time error can sometimes be reduced by using light gates and electronic timing or sensors connected to a computer to record time taken for objects like paper cake cases to fall or a vehicle to move down a slope
Parallax error
Parallax error is caused by a student not reading the measurement at eye level. It can lead to the reading being too high or too low.
Systematic errors (zero errors)
Zero errors are caused by faulty equipment that doesn’t reset to zero properly.
Check before you start measuring that the measuring instruments read zero for zero input.
A zero error would affect every reading you take. The digital balance will be wrong by 0.02 g on every mass you measure and the force meter would be wrong by 1 N.