EarthLabs for Educators > Climate and the Cryosphere > Lab 3: Land Ice

Lab 3: Land Ice

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

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Investigation Summary and Learning Objectives

Glaciers are formed by snow compressed over many years. Annual layers of snow are similar to tree rings. Photo by drurydrama (Len Radin). Image source: Flickr

In the first part of this lab, you will learn about how glaciers form and the different processes that contribute to glacial mass balance by using an online interactive to explore how glaciers provide scientists with evidence for climate change. In Part B, you will learn about how & why glaciers move. In Part C, you will make a model of a glacier out of a putty-like substance called gak and conduct a hands-on experiment to explore glacial movement.

After completing this investigation, students will be able to:


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


Activity Overview and Teaching Materials

In Part A: Students begin by reading this excerpt about land ice (Acrobat (PDF) 305kB Jul2 11) from the NSIDC page All About the Cryosphere. They then explore glacial accumulation and ablation processes using an online interactive produced by the University of Kentucky that shows them how scientists are able to determine whether a glacier is growing or shrinking and whether changes in the glacier's mass balance are related to climate change.
Time estimate: 25-50 minutes

In Part B: Students read a short background essay and watch the NOVA Science NOW video Fastest Glacier (running time approximately 5 minutes). They then do a simple experiment that demonstrates how a layer of melted water acts as a lubricant that speeds up glacial movement. This experiment can also be done by teacher as a demonstration at the front of the class. As a class, discuss the content of the video and how it relates to the experiment/demonstration.

Materials:

Encourage interested students to explore more about how scientists measure the speed of glaciers using the link in the How Do We Know What We Know? section. Time estimate: 50-75 minutes

In Part C: Students make a model glacier out of homemade silly putty, sometimes called goo, gak, or flubber. You will need the following materials for each group of students:

If you'd like to have students compare the effects of different glacier flow rates, have them play around with the proportions of Borax and water in their gak recipe. Here are two tested recipes:

Recipe 1 (faster-moving):

To make the gak:

  1. In a mixing bowl, combine 3/4 cup warm water and 1 cup glue. Stir until well mixed.
  2. In a second mixing bowl, combine 1/2 cup warm water and 1 tsp of Borax powder and stir until the powder is fully dissolved.
  3. Combine the contents of the two mixing bowls, and stir until a glob forms.
  4. Put half of the glob back into the first mixing bowl. Add a few drops of food coloring.
  5. Use your hands to knead the mixture in each bowl until it is well mixed (approx. 2-3 minutes). Wear rubber gloves to prevent staining your hands with the food coloring.
  6. Break off pieces of the white gak and pieces of the colored gak. Lay them out in strips of alternating color. Smush the strips together to reform a single striped glob of gak.

Recipe 2 (slower-moving):

To make the gak:

  1. In a mixing bowl, combine the glue & 2 oz cold/room temperature water. Stir until well mixed.
  2. In a second mixing bowl, dissolve borax in hot water & slowly add it to glue mixtureworking quickly, as the mixture will thicken.
  3. Put half of the glob back into the first mixing bowl. Add a few drops of food coloring.
  4. Use your hands to knead the mixture in each bowl until it is well mixed (approx. 2-3 minutes). Wear rubber gloves to prevent staining your hands with the food coloring.
  5. Break off pieces of the white gak and pieces of the colored gak. Lay them out in strips of alternating color. Smush the strips together to reform a single striped glob of gak.
Time estimate: 50-75 minutes

Printable Materials

To download one of the PDF or Word files below, right-click (control-click on a Mac) the link and choose "Save File As" or "Save Link As."


Teaching Notes and Tips

In Part A: Consider assigning reading as homework.

In Part B: Consider projecting the video for students to watch together as a class. Be prepared to facilitate a discussion and give a simple demonstration of how meltwater beneath a glacier makes the glacier flow faster. Slide a wooden block across a table or desk. Then slide an ice cube across the same surface. Have students discuss how each object behaved. Which object slid more easily? Now try sliding the wooden block across a wet surface. Discuss how the water acts as a lubricating layer between the block and the table just as it does between the Jakobshavn glacier and the underlying land.

Consider assigning "Background Essay: Fastest Glacier" reading as homework.

Purpose of the discussion: This discussion will help solidify what students learned about glacier movement in the Fastest Glacier video and the wooden block experiment.

Facilitation Tips: Write the primary discussion questions 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 questions:

  • Which object in the experiment slid more easily?
  • How does this experiment mimic what's happening with the Jakobshavn glacier?

Wrap Up: Before moving on, make sure students see the connections between the lubricating layer of water and the speed of the glacier (and the wooden block). Although scientists are still trying to determine the exact cause for the Jakobshavn glacier's record speed, their observations indicate that warming temperature is the primary contributor. As this glacier surges toward the coast, large amounts of freshwater ice and water are being dumped into the ocean. As students learned in Lab 2, this could have serious consequences for ocean circulation. Studying the Jakobshavn glacier and other glaciers will help scientists better understand how climate and the cryosphere influence one another.

In Part C: If time is tight, consider making batches of gak before class. After the lab, place the gak in a ziplock bag and save it for future use or dispose of it in the trash.


Student Notebooks

Suggestions for how to use Student Notebooks for Lab 3:


Assessment

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 3 (Microsoft Word 2007 (.docx) 2.4MB Jan9 13). (Test key (Microsoft Word 2007 (.docx) 2.5MB Jan9 13))

National Science Teaching Standards

Lab 3 supports the following Next Generation Science Standards (NGSS):

Science and Engineering Practices
2. Developing and using models
4. Analyzing and interpreting data
7. Engaging in argument from evidence

Disciplinary Core Ideas
ESS2.C: The Roles of Water in Earth's Surface Processes

Cross-Cutting Concepts
2. Cause and effect; mechanism and explanation
4. Systems and system models
7. Stability and change

NGSS Lab 3C



Additional Resources

Background Information


Content Extension


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