EarthLabs for Educators > Climate and the Cryosphere > Lab 2: Earth's Frozen Oceans

Lab 2: Earth's Frozen Oceans

The lab activity described here was developed by Erin Bardar of TERC for the EarthLabs project.

Open the Student Activity in a New Window Use the button at the right to navigate to the student activity pages for this lab. To open the student pages in a new tab or window, right-click (control-click on a Mac) the "Open the Student Activity" button and choose "Open Link in New Window" or "Open Link in New Tab."

Investigation Summary and Learning Objectives

Sea Ice
Arctic sea ice. Image source: NOAA Photo Library via NASA Earth Observatory.

In Part A, you will learn about how sea ice forms and influences ocean currents around the globe. In Part B of the investigation, you will look at how sea ice thickness changes over time. Finally, in Part C, you will use NSIDC sea ice index data to explore changes in sea ice extent on multiple time scales including months, years, and decades.

After completing this investigation, students will be able to:

For more information about the topic, check the section titled Background Information under Additional Resources below.

Activity Overview and Teaching Materials

In Part A:, students are introduced to sea ice and how it is connected to ocean circulation. They begin by watching the BBC/Discovery Channel video Frozen Planet: Icy Finger of Death from the popular television series Frozen Planet. They then conduct an experiment to explore how salinity affects the density of ocean water and how the formation and melt of sea ice influences ocean currents all around the globe. For each small group of students, you will need:

After completing the experiment, students use an online interactive to explore thermohaline circulation in more detail. (NOTE: This interactive will require student computers to have an up-to-date version of Flash.) Next, students watch a brief, narrated NASA video showing the thermohaline circulation system in three dimensions. (NOTE: This video may require Real Player to be installed on student computers.)
Time estimate: 50-75 minutes

In Part B: Students examine a plot of sea ice thickness over the course of a year to help them understand the role of heat transfer between the cryosphere and atmosphere. They then consider the dynamic forces that influence sea ice thickness and watch a short YouTube video showing the vertical undulating motion of sea ice. Next, students interpret images showing how sea ice age (thickness) has changed in recent years and learn about the Arctic Oscillation, a large-scale seesawing weather pattern that affects sea ice extent and thickness. Interested students can use the Measuring Sea Ice Thickness Power Point presentation under How Do We Know What We Know?, as a launching pad for further investigation of some of the tools and techniques scientists use to measure sea ice thickness.
Time estimate: 50-60 minutes

In Part C: Students focus on sea ice extent, looking at how sea ice extent varies on seasonal and annual time scales. They will create an animation of Arctic sea ice extent changes over the course of one year and then five years using the National Snow and Ice Data Center's Sea Ice Animation Tool. They will then use Microsoft Excel or another spreadsheet program (if available) to plot monthly sea ice extent for one year. Part C ends with a wrap-up discussion about what students have learned about sea ice formation, extent, thickness, and changes over time.
Time estimate: 50-100 minutes

Printable Materials

Teaching Notes and Tips

In Part A: If time or supplies are limited, the density/circulation experiment can be done as a front-of-the class demonstration.

In Part B: If YouTube is blocked on your school computers, consider one of the following options:

In Part C: To save time, you might consider assigning a different year to different small groups of students rather than have all groups collect and graph data for all 5 years.

Purpose of the discussion: In this lab, students were introduced to Arctic sea ice, which helps regulate ocean circulation and global climate. Use this discussion opportunity to make sure students understand the role of sea ice and why it is important for scientists to monitor and understand how it changes over time.

Facilitation Tips: Write the primary discussion question on the board and give students three minutes to share ideas in pairs or to write in their notebooks before starting the full class discussion.

Primary discussion question: Why is it important to understand how sea ice changes over time?

Supporting questions:

  • What causes sea ice thickness and extent to change over time?
  • What types of changes do scientists expect to see in sea ice over a year? over 5 years or more?

Wrap Up: Even though sea ice is found primarily in the polar regions, it influences the whole world. Changes in the amount of sea ice can disrupt normal ocean circulation, which directly impacts global climate. Sea ice is also highly reflective and plays a large role in keeping the planet cool. As they continue through the cryosphere unit, students will learn more about the importance of sea ice as a climate indicator.

Student Notebooks

Suggestions for how to use Student Notebooks for Lab 2:


There are several options for assessment of student understanding of material introduced in this lab. Choose from the following list, or create your own assessments.

Assessment Options:

  1. Assess student understanding of topics addressed in this investigation by grading their written responses to the Stop and Think questions or by using Stop and Think questions as part of whole-class or small group discussions.
  2. Written Test for Lab 2 (Microsoft Word 2007 (.docx) 245kB Jan11 13). Answer key (Microsoft Word 2007 (.docx) 445kB Jan11 13)

National Science Teaching Standards

Lab 2 supports the following Next Generation Science Standards (NGSS):

Science and Engineering Practices
4. Analyzing and interpreting data
7. Engaging in argument from evidence

Disciplinary Core Ideas
ESS2.A: Earth's Materials and Systems
ESS2.D: Weather and Climate

Cross-Cutting Concepts
1. Patterns
2. Cause and effect; mechanism and explanation
4. Systems and system models
5. Energy and matter; cycles, flows, conservation
7. Stability and change


Additional Resources

Background Information

Content Extension

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