Here is the tool to introduce travel graph.
It records the relationship between the distance traveled and the time used of a journey.
By varying point B& C, students can read the speed changes shown in the right.
They may notice that the gradient of the line is directly proportional to the speed.
This travel graph also included the negative side.
It is used to remind students the following point of misconception.
If student moves the point C to the negative side, the overall speed is not solely calculated by used line AC, but he has to add up all distance traveled, and divided by total time used.
