Lesson 2.6: Show Change Through Time
Lesson
Introduction ![]530 The previous section reviewed covaration - looking for relationship between two numerical attributes. A special kind of covariation inquiry is investigating how much something (such as temperature or sea level) changes through time. Analyzing data for questions about change through time requires two numerical attributes, one of which is a measure of continuous time, e.g. seconds, minutes, hours, days, months, years, or even millenia. Data that include a time attribute that orders the data are called “time series”. Graphing change through time at different timescales is a great way for students to engage with the NGSS Crosscutting Concepts of Scale and Patterns of Change, as well as to distinguish between stable and changing conditions in the world around them. This lesson reviews ways to investigate change through time and how to summarize change through time with a trend line. It reviews some typical patterns found in time series, and how students can informally distinguish between “signal” and “noise” to decide (informally) whether something is stable or changing. Key concepts for students: Recognize time series data and identify timescales (seconds, months, millenia, etc.) Connect dots in a scatter plot - that is, make a line graph - when appropriate, to highlight change through continuous time. Use the concept of trend to describe the quality (and quantity) of change through time Recognize and interpret patterns of change (e.g. increasing, decreasing, cyclic, nonlinear) Distinguish between stability and change, and signal and noise in a time series graph. Key words: Trend, Least Squares Line, Signal, Noise, Cyclic, Linear, Time Series, Line Graph, Slope, Rate of Change
Topics and standards: Time Series