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Human Energy Systems | Activity 1.5

Activity 1.5: Finding a Trend in Arctic Sea Ice (20 min)

Students return to their arctic sea ice graph from Activity 1.2 and draw a trend line. Then they watch a short video from NOAA that shows the trend they have been talking about: arctic sea ice decline.

Materials You Provide

Resources Provided


Print one copy of the 1.5 Finding a Trend in Arctic Sea Ice Worksheet for each student. Prepare a computer and projector to display the presentation. Retrieve students’ completed 1.3 Graphing Arctic Sea Ice Worksheet with their graphs of arctic sea ice data.


1. Review steps for drawing a trend line.

Return to students their completed copies of 1.3 Graphing Arctic Sea Ice Worksheet. Have them eyeball the data in their graphs and share if they see any trends in the data based on the numbers and graph. Tell them that now that they know how to draw trend lines, they will look for a trend in their Arctic Sea Ice data. Open 1.5 Finding a Trend in Arctic Sea Ice PPT.

  • Use Slide 2 to have students recall the steps they took to draw a trend line on the Lake Superior graph. Record their ideas on Slide 2. If they forget, remind them of the steps:
    • Step 1: Connect the dots.
    • Step 2: Divide the picture into sections by drawing vertical lines on the graph every five years.
    • Step 3: Calculate the average of all the data points within those five year time periods.
    • Step 4: Place one dot in each section that shows the average for that time period.
    • Step 5. Draw a line to connect the new dots.


The most important ideas to listen to in this lesson are how students describe the long-term trend. Do they see that the trend shows that arctic sea ice is declining? Use their ideas on 1.5 Finding a Trend in Arctic Sea Ice Worksheet to determine where they are in their thinking at this stage. Look to see if they feel comfortable using the trend as evidence to make a prediction about what will happen in the future. At this point in the lesson, students should be able to explain that all data representations represent the same system, but in different ways. Listen to their ideas in the final discussion using Slide 7 to determine if they are comfortable explaining why and how scientists simplify large data sets to identify trends, or if they need to revisit the activity before moving on.


When watching the video, students may need help identifying the difference between (a) seasonal variation of ice extent between winter and summer, and (b) the overall declining trend.

Extending the Learning

  • Have students research any other forms of representations of data related to arctic sea ice extent. They might be surprised to discover how many different ways there are to represent the same data.