Distance / Time Graphs

Overview

Ben and Katie are required to undertake contrasting journeys in order to gather data to demonstrate the construction of distance-time graphs. We follow Ben's experiences with the pop group Atomic Kitten and Katie's flying visit to Belgium via the Channel Tunnel, gathering the material to draw distance-time graphs and to discuss their properties. We see how to:

• choose sensible scales for the axes and plot significant points
• find the average speed for a section of a journey and relate this to the gradient of the graph
• calculate the speed using the formula 'speed = distance ÷ time', taking values from the graph
• show a period of rest as a horizontal line segment
• represent return journeys and understand negative gradients in this context
• calculate using appropriate units for distance, time and speed

The content is linked to the requirements of GCSE Intermediate Mathematics. It includes tips for answering exam questions, and a discussion of a typical exam error ('Tick or Trash'). It shows how real journeys can be plotted and analysed using graphs and aims to demonstrate the mathematical ideas using contexts that are appealing and readily understood by the student.

The programme could be used either as an introduction to the topic or as revision. It highlights contexts likely to arise in GCSE-level exams.