Title

Drawing Conclusions: Formulating conclusions based on evidence, evaluating the validity of the experiment, and proposing further investigations. 

Any source of errors that may have affected the results should be mentioned, e.g. the stopwatch was not always started at exactly the same time as the trolley was released/pushed.

Describe any improvements that would make the results of the investigation more valid, e.g. putting up barriers to make the trolley travel in a straight line and carrying out more trials so the calculated average journey time is valid.