HES Activity 2.1 Assessment


A key opportunity for formative assessment in this activity is during the consensus-building discussion about the arctic sea ice column. During this discussion, encourage the students to compare and contrast each other’s ideas, with the goal of finding an answer to each box that they all agree is supported by the evidence. Use this key as a guide:


  • What variables
  • What time period?


  • Which regions are included?
  • What does this tell you about global patterns?

Short-term variability

  • What is the short-term variability in the data?
  • Is it predictable or unpredictable?

Long-term trends

  • What is the long-term trend?
  • Is it predictable or unpredictable?

The extent of Artic sea ice (millions of square kilometers) each October from 1979-2013 is represented on the graph.

This graph is specific to ice in the Arctic Ocean and may not be representative of patterns in ice in other bodies of water.

The extent of ice fluctuates up and down in an unpredictable way each year, but the overall trend is a decrease in sea ice extent over the period of 1979-2013.

The long-term trend shows that arctic sea ice has decreased. It is predictable.


  • It is best not to move on to the next activity until students have a solid understanding of the “four considerations” presented in this activity.
  • Tell students to keep their jigsaw cards for the next activity.
  • The worksheet for the CO2 trend line (Group B) is the longest and most complex. Consider assigning cards labeled “B” to more advanced students when you pass out the jigsaw cards in this activity.
  • Collect and keep students’ 2.1 Finding Patterns Tool for Earth Systems in a place where they can be found easily again later. Use the 2.1 Assessing the Finding Patterns Tool for Earth Systems to assess their ideas at this stage in the unit.