Interpolation and extrapolation

Interpolation and extrapolation

One major source of errors in student investigation is the lack of an adequate data set in terms of the range and number of samples of data. (See ‘Conducting Investigations’ level 2 learning pathway for a treatment of the need for replication or repetition to ensure reliability of data). For example, if students are investigating the impact of drop height on the diameter of the impact crater, they may need to have selected more than two heights from which to drop the object. Not only does there have to be a sufficient number of samples, but the range over which the object is dropped has to be sufficiently large. Four sample heights at 1.0 m, 1.2 m, 1.25 m and 1.3 m may be an adequate number of samples, but they may be taken over too small a range. For many students their accuracy of maintaining these height differences and measuring small differences in crater diameter may mean that results do not show any noticeable differences.