Science with Flubber: Glacial Isostasy

Megan Berg (UNAVCO), Beth Bartel (UNAVCO), Shelley Olds (EarthScope Consortium), Daniel Zietlow (UNAVCO), & David Thesenga (Alexander Dawson School); based on an activity developed by POLENET - The Polar Earth Observing Network
EarthScope Consortium logo. Concentric circles in red grading to purple.
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Summary

Using two sets of flubber, one representing the Earth and one representing a glacier, demonstrate how the crust sinks and rebounds to the weight of a glacier, and how this motion can be measured using GPS. Flubber is a rubbery elastic substance, a non-Newtonian elasco-plastic fluid, that flows under gravity, but breaks when under high stress. Flubber is useful for demonstrating a wide range of Earth and glacier processes.

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Context

Audience

This demonstration can be used in any introductory earth science course to complement instruction regarding the behavior of the earth in response to glaciers.

Skills and concepts that students must have mastered

None

How the activity is situated in the course

This demonstration can be used at any time in an earth science class particularly within lessons about glaciers, climate change, and applications of GPS data. It can be used as an introductory demonstration for students to explore how the crust is flexible. The demonstration takes about 5 - 20 minutes of class time.

Goals

Content/concepts goals for this activity

This demonstration shows how the crust sinks and rebounds to the weight of a glacier, and how this motion can be measured using GPS. It uses flubber as a proxy to both crust and glacier to show their reactions.

Key concepts covered:

  • The crust is not always rigid.
  • Glaciers can affect the shape of the Earth.
  • As a glacier grows, the weight of the glacier depresses the crust downward. As a glacier shrinks, the crust rebounds upward in the area around the glacier.
  • We can use GPS to measure how glaciers are changing by measuring elevation changes over time of the land around them.

Higher order thinking skills goals for this activity

Other skills goals for this activity

Description and Teaching Materials

How To Make Flubber (Acrobat (PDF) 45kB Oct31 21)

Teaching Notes and Tips

A full video of the Science with Flubber: Glacial Isostasy Demonstration can be found on the UNAVCO YouTube channel.


Assessment

This is intended to stimulate student interest and initial understanding of glaciers or crustal studies to come. There is no formal assessment. Educators can ask questions to stimulate discussion and do formative assessment of learner understanding.

References and Resources