This lesson picks up on the idea planted in the previous lesson about creating linear models for data. Specifically, in some situations where a quantity changes at different constant rates over different time intervals, we can model the situation with a piecewise linear function (MP4). Students look at temperature data, which change at different rates throughout the day. The rates for these intervals are almost constant. They also use piecewise linear graphs to find information about the real-life situation they represent. The focus of this lesson is not necessarily to find equations for the piecewise linear functions (though students may choose to do so in some instances), but rather to study the graphs qualitatively and to compute and compare the different rates of change.

The fourth activity is optional. Use this activity to give students additional practice describing a piecewise linear function that represents a context.