In this activity from Chapter 4 of *EDC Earth Science*, students study temperature and precipitation data from NOAA’s National Climate Data Center for two states over a 100+ year period.

**Reading and comparing data values in graphs. **Initially, students answer specific questions about the data presented in each graph, such as “Which three years had the highest average annual temperatures?” and “Which three years had the lowest average annual temperatures? What were these temperatures?” These questions focus students on accurately reading and comparing data values that are presented in each graph.

**Considering variability. **Students then consider, in particular, the variability that is evident in these data (and that is typical of complex systems such as weather), for example, finding two years in a row that had very similar and very different average temperatures.

**Studying long-term trends. **After studying and comparing individual data points and exploring their variability, students focus on the long-term trend that has been calculated and presented as the trend line in the graphs. “Do you see a trend in this graph? Write a sentence that describes what the trend line shows.”

**Comparing the same data type in two different graphs. **To explore the regional variability in climate, students then compare the temperature data for the two states, in this case New Hampshire and Arizona. They compare, for example, the highest and lowest annual temperatures in the two states, the overall shape of the curves in the two graphs, and the trend lines. [Note: They also focus on the different temperature ranges shown on the x-axis of the graph for the two states and are asked “Why do you think these are presented differently?”]

**Calculating averages from data tables. **Students look more closely at temperature data from a recent 30-year period. Using tabulated data, they calculate and compare the average temperatures in the two states during this 30-year period. They are encouraged to think about these two averages, and articulate their ideas about why the average temperature is different in the two states.

**Considering different data types. **Students then study precipitation data over the same 100-year and 30-year time periods for the two states.

**Obtaining and evaluating customized data sets. **After studying the provided data from New Hampshire and Arizona, students then use the Internet to obtain similar data from their local area and a selected travel destination. They evaluate and compare these data, and consider how the climate in their travel destination might make their experience different from home.