Explain the term 'area of a surface'.

Name the S.I. unit of area and define it.

(a) Describe in steps how would you measure the length of a pencil using a metre ruler. Draw a diagram if necessary.

(b) Explain with an example how you will use the metre ruler in part (a) if the ends of the ruler are broken.

Name the instrument used for measuring the temperature of a person. Draw its neat labelled diagram.