Human Energy Systems | Activity 1.5

Return to students their completed copies of 1.3 Graphing Arctic Sea Ice Worksheet. Have students use the same procedure to draw a trend line on the arctic sea ice graph on their graphs. Give them about 15-20 minutes to draw the trend line. After they are done, have the students pair with others and compare/contrast their trend lines.

Give each student a copy of 1.5 Finding a Trend in Arctic Sea Ice Worksheet. Tell them to complete the worksheet, which requires them to hand sketch their arctic sea ice table and explain the trend line in their own words. Give students about 10 minutes to complete the worksheet.

When students have finished their worksheets, discuss these ideas as a class. Use slide 5 to instruct students to Turn and Talk with a partner.

• Ask the pairs to compare their descriptions of their trend lines (number 3 from their 1.5 Finding a Trend in Arctic Sea Ice Worksheet). Listen to their ideas: do the pairs all share an agreement that they see a negative, downward trend?
• Use slide 6 to have students share descriptions of the trend they see. Do they see a positive trend, a negative trend, or no change? Have them explain how they know that (i.e., their evidence), and develop a class description of the trend. Record the class description on the slide.
• At this point, see how easily the students arrive at a class consensus that there is a downward trend in the data. If some students’ ideas are different, discuss the differences and see if (as a class) you can reach consensus for the reasons for the differences.

Use slide 7 to instruct students to Turn and Talk again, but this time with a different purpose. Now that the class has reached the consensus that the data show a downward trend, what does that mean?

• As partners to share their ideas from number 4 on their 1.5 Finding a Trend in Arctic Sea Ice Worksheet.
• After the students talk with their partners, use slide 6 to construct and revise a class explanation for what is happening to arctic ice. Write down their class explanation. Continually ask students if they have additions or suggestions for changes that will make the explanation more clear, or more strongly supported with evidence from the graph.
• Have students complete #3 on their worksheet, which asks them to write a description of their trend and to label it positive, negative, or no change.

After students have shared their own graphs, display slide 8 of the presentation that shows NOAA’s version of the graph’s trend line. Have the students compare their own trend lines to NOAA’s.

• Ask students to note any differences between NOAA’s graph and their graph. They might notice, for example, that this graph shows data for the month of October, not September. They may notice other details that are different as well.
• Remind them that they are comparing trend lines. How is their trend line similar or different to NOAA’s? Students should notice that both graphs show a negative trend, even though the months are different.
• Point out that because this is data from a different month, the short-term variation will be different, but the long-term trend will be the same: it will be negative.
• Use slide 9 to compare the short-term variability of the October and September graphs. Use this to point out the similar long-term trends, but different short-term variability.

Have students watch the one-minute video from NOAA that shows arctic sea ice extent from 1987-2014.

• Watch the video once through, and then watch the video again. The second time through, pause the video in various places to help the students look for specific elements of the video that helps them interpret what they are seeing. During the discussion, help them connect the pieces of the video to their explanations for what is happening.
• Pause the video at 17 seconds. Have them identify where in the video they see old ice, and where in the video they see seasonal ice. Point them to the color legend as a reference and ask a student to explain what the legend tells them.
• Pause the video at 20 seconds when it is winter on the Northern Hemisphere. Have them identify the moving dial that shows it is winter.
• Pause the video again when it is summer in the northern hemisphere. Have them discuss the difference between what they see in the winter and in the summer. See if they notice that there is more change in the seasonal ice (dark blue) than in the old ice (white).
• Pause the video again right before the end (around 1:00). Ask the students to describe the difference in the amount of old ice in 2014 as compared to 1987.

Show Slide 10 of the 1.5 Finding a Trend in Arctic Sea Ice Worksheet.

• Pass out a Learning Tracking Tool for Human Energy Systems to each student.
• Explain that students will add to the tool after activities to keep track of what they have figured out that will help them to answer the unit driving question.
• Discuss goals for this lesson.
• Have students write the activity name in the first column, "Questions for this Lesson."
• Have a class discussion about what students figured out during the activity that will help them in answering the lesson driving questions:
• What causes the annual cycle: CO₂ concentrations in Hawaii to go down every summer and up every winter?
• What causes the long-term trend: CO₂ concentrations to go up every year?
• How can we predict what will happen to CO₂ concentrations in the future?
• When you come to consensus as a class, have students record the answer in the second column of the tool.
• Have a class discussion about what students are wondering now that will help them move towards answering the unit driving question. Have students record the questions in the third column of the tool.
• Have students keep their Learning Tracking Tool for future activities.
• Example Learning Tracking Tool