Lab 3: Land Ice
The lab activity described here was developed by Erin Bardar of TERC for the EarthLabs project.
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
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:
- describe how scientists use glacial mass balance to look for changes in climate;
- describe how glaciers move and shape Earth's surface;
- create a model of glacial movement using gak/flubber; and
- describe how we know what we know about glacier dynamics
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 ThinkTV 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:
- Small wooden block
- ice cube
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:
- 1 tsp Borax powder
- 1 & 1/4 cup warm water
- 1 cup white glue
- 2 mixing bowls
- popsicle sticks, for stirring
- food coloring
- rubber gloves
- airtight container or ziplock bag
- chute made from PVC Pipe or cookie sheet (Also, the suggestion to use a short piece of plastic rain gutter for the chute is one that came from teachers. An 8-foot or 10-foot section of rain gutter is very inexpensive and easy to cut up into 2-foot lengths for students just with a good pair of scissors. And for a slow-moving glacier, a 2-foot section would be plenty long.)
- books to prop up chute
- dry erase marker
- ruler
- timer
- plastic drinking straw
- 5 ml water
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."- PDF of excerpt about land ice (Acrobat (PDF) 305kB Jul2 11) from the NSIDC page "All About the Cryosphere"
- Background Essay: Fastest Glacier (Acrobat (PDF) 40kB Jul3 11)
- Stop and Think Questions (PDF (Acrobat (PDF) 35kB Jan4 13) and Word (Microsoft Word 31kB Jan4 13)
- Suggested Answers (Microsoft Word 153kB Jan10 13) to Stop and Think Questions
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.
Show glacier dynamics discussion guidelines
HidePurpose 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.
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:
- Assess student understanding of topics addressed in this investigation by grading their responses to the Stop and Think questions.
- Written Test for Lab 3 (Microsoft Word 2007 (.docx) 2.4MB Jan9 13). (Test key (Microsoft Word 2007 (.docx) 2.5MB Jan9 13))
State and National Science Teaching Standards
Cryosphere TEKS Alignment (Microsoft Word 127kB Nov15 11)
Cryosphere lab activities are aligned to standards in this document:
Developer will correlate activity to standards listed at this site:
National Science Education Standards (SRI)Additional Resources
Background Information
- NSIDC's All About Glaciers: Moving Forward
- Glacial Processes
- Background Essay: Tracking Glacial Clues for Climate Change (Acrobat (PDF) 48kB Jun30 11)
- In this unit, we'll be using the term "land ice" as a catch-all term for ice that formed over land primarily from freezing precipitation (as opposed to sea ice, which forms by the freezing of seawater). This includes:
- NASA Earth Observatory article Sizing up the Earths Glaciers
- Eyes in the Sky II Week 2: Intro to ImageJ techniques including how to measure and set a scale.
- Retreat of Andean Glaciers Foretells Global Water Woes: Article about the impacts the rapid loss of glaciers has on vital water supplies.
Content Extension
- National Geographic Feature Article: The Big Thaw
- Earth Exploration Toolbook Chapter Is Greenland Melting?
