Lesson 7
Behaviour Over Time
Read the shape of a line over time as a fingerprint of the loops and delays behind it, and know what a shape can and can’t tell you.
Put time along the bottom
A behaviour-over-time graph is the simplest picture in this course: time along the bottom, one named quantity up the side, with its units. The laundry pile each evening. The pothole list each week. Your current account on the last day of each month.
One reading is a snapshot. A line through many readings shows what the quantity is doing: climbing, levelling, swinging, falling. And because each kind of loop leaves its own mark on the line, the shape is a clue to the structure behind it.