This video features University of Wisconsin-Madison researcher John Magnuson, who studies the ecology of freshwater systems. He explains the difference between weather and climate using data on ice cover from Lake Mendota in Madison, WI. Analysis of the data indicates a long-term trend that can be connected to climate change.

In this activity, students are guided through the process of locating and graphing web-based environmental data that has been collected by GLOBE Program participants using actual data collected by students in Pennsylvania and comparing them to their local climatic boundary conditions. This activity highlights the opportunities for using GLOBE data to introduce basic concepts of Earth system science.