Human Energy Systems | Activity 1.3

Remind students that in this unit we will be examining systems at larger spatial and temporal scales than in previous units. This presents a problem: How do we know when we’ve looked at ENOUGH data to see a difference that is important? How do we know which data to pay attention to? In this lesson, we will explore these ideas.

Explain that scientists use many different representations of data to help them understand and communicate what is happening to arctic sea ice. In this activity, they will use data that scientists have collected to make a graph. But why do scientists do things like this? Ask students to share any examples they know about ways scientists and other people represent information:

• Open 1.3 Graphing Arctic Sea Ice PPT. Use slide 3 to elicit student ideas about different ways scientists and other people represent data. The pie chart is one example. Ask them for other ideas and record their ideas on the slide.
• Use slide 4to then ask them why scientists do this. For example, why would scientists want to use a pie chart instead of numbers to represent data? Ask students to explain why each of the forms they suggest might be useful. Help students think about Representation: what different information (time period, data, etc.) can be displayed using different representations?
• Finally, use slide 5 to ask students why we might be using a graph to represent changes in arctic sea ice. Listen to their ideas and add (if necessary) that the graph will help us identify patterns in the data that we might not be able to see so easily in the images and numbers. Ask: What will a graph allow us to see that these images don’t?

Some students may benefit from a brief refresher on the components of a graph.

• Use slide 6 to overview the primary components that they will use to represent the arctic sea ice data: the title, vertical axis, horizontal axis, units, and axis labels.
• Using the prompts on slide 7, assess your students’ graph-reading practices: What does the horizontal axis in this graph tell us? What does the vertical axis tell us? What do these graphs tell us about rainfall?
• Use the Turn-and-Talk strategy to have students construct a 3-5 sentence description of the information in the graph.

Use the results of this turn-and-talk to assess if your students are able to proceed with the graph construction.

Tell students that it is their job to use data that scientists have collected about arctic sea ice to construct a graph. Go to the link above and demonstrate how to use the website to find different data points from different years.

• Demonstrate how to find data by entering Hemisphere→ Northern, Start Year → 1979, Start Month→ September, and Image→ Sea Ice Extent. Check the "Fixed Month Animations" Box. You should see the data point at the bottom of the image: Total Extent = 7.2 million sq km. Advance the viewer one year at a time by clicking the "1>" button.
• Distribute one copy of 1.3 Graphing Arctic Sea Ice Worksheet to each student.
• Tell students to input this first data point into the table (not graph) on Page 1 of their worksheet. Wait to see if there are any questions about this.

There are two options for this step:

• Option 1: Instruct students to go to the website themselves and collect the data to complete Table 1. If you choose this option, demonstrate for students how to find the data for 1979 as an example.
• Option 2: Use the images in the presentation (Slides 10-45) to have students complete the table.

Use slides 8-9 of the PPT to overview their options and to show them where to find the data on the images.

After the table is completed but before constructing the graph, ask students for their ideas about the data as represented by numbers (in the table) and pictures (in the presentation or online).

• Ask students: What patterns do you see in the numbers? What patterns do you see in the pictures?
• Scroll through the images in the presentation again if necessary. Listen to the students’ ideas at this point. Do they notice any patterns? Do the different representations allow them to notice anything different in the data? If so, which ones? If not, why not?

Tell students it is their job to plot the data points from their data table onto the graph on Page 2 of their worksheet.

• Divide students into pairs.
• Instruct one student to read the data points, and the other to plot the graph.
• Give students about 10 minutes to construct their graphs.
• Remind students that the graphs need labels for title and axes, too.

Have students share with the class what they chose for their axis labels and their titles. Ask students to look at the graphs and ask them: What does this graph let you see that the numbers and the pictures did not? Why do you think graphs like this are helpful tools for scientists? Tell students that in the next activity they will look for a trend in the graphs.

• Help students compare the three different representations in this activity: the images, the table, and the graph. Lead a short discussion about how different representations allow us to look at data differently.

• Show Slide 50 of the 1.3 Graphing Arctic Sea Ice PPT.
• Conclusions: How does the amount of Arctic sea ice change from one year to the next?
• Predictions: How has the amount of Arctic sea ice changed over the last 20 years?
• On a sheet of paper or a sticky note, have students individually answer the exit ticket questions. Depending on time, you may have students answer both questions, assign students to answer a particular question, or let students choose one question to answer. Collect and review the answers.
• The conclusions question will provide you with information about what your students are taking away from the activity. Student answers to the conclusions question can be used on the Driving Questions Board (if you are using one). The predictions question allows students to begin thinking about the next activity and allows you to assess their current ideas as you prepare for the next activity. Student answers to the predictions question can be used as a lead into the next activity.