Download ES18-Understanding the Asthenosphere

Classroom Teacher Preparation
Earth Science 18: Understanding the Asthenosphere
Please use the following to prepare for the next SfS lesson.
Description:
The asthenosphere is generally presumed to be a solid, but it is a solid that can flow over long time periods. This lesson
gives the students hands-on practice with two different viscoelastic materials that also exhibit the behaviors of both solids
and liquids in order to promote understanding of the properties of the Earth’s asthenosphere.
Lesson Objectives – SWBAT (“Students Will Be Able To…”):
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Understand that Earth’s asthenosphere is a viscoelastic solid that can flow
Explain how this understanding of the asthenosphere supports our theory for the movement of Earth’s tectonic
plates
Evaluate oobleck and Silly Putty as potential physical models for Earth’s asthenosphere
Preparation:
Students should be familiar with the structure of the earth and should know that the earth’s tectonic plates are moving on
the flowing asthenosphere.
Pre-requisite lesson:
Earth Science 2: Intro to Tectonics or recent coverage of this topic in the classroom are required for understanding and
appreciation of this module topic.
Vocabulary:
Introduce these terms (many are covered in the pre-requisite module ES02):
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Core – the innermost layers of the earth; it includes the inner and outer core
Mantle – the portion of the earth between the crust and the core; it makes up about 45% of the Earth’s interior
o Note that the uppermost part of the mantle is solid and is also part of the lithosphere
Crust – the solid outermost layer of the Earth
Lithosphere – the rigid, outermost layer of the Earth, composed of the crust and the solid upper part of the mantle
Asthenosphere – the semi-solid part of the mantle immediately below the lithosphere
Tectonic plate – an irregularly-shaped piece of the lithosphere
These terms will be defined in lesson:
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Elasticity – the property of a substance that enables it to change its shape under a stress and then recover its
original form when the stress is removed
Plastic – able to undergo a change of form without breaking
Viscosity – the speed at which a liquid flows; can be thought of as a measure of friction within a liquid
Viscoelasticity – the property of a substance of exhibiting both viscous (flowing) and elastic characteristics under
stress
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Room Set Up for Activities:
Students will work in pairs while experimenting with Silly Putty and small samples of the cornstarch-and-water mixture
known as “oobleck.” No special equipment is needed, but the oobleck has the potential to be messy. Instructors will be
prepared with paper towels and a pitcher of water for rinsing hands; access to a dustpan and broom may be useful.
Safety:
There are no safety issues with this lesson.
Related Modules:
This lesson may be taught as part of a sequence or group of related modules on Earth Science, in particular regarding
the structure of the earth or earthquakes. Modules include:
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Earth Science 9: Rock Cycle: The three rock types found on Earth (igneous, sedimentary and metamorphic) are
discussed and their specific characteristics are identified. Students will examine and identify rock samples using a
dichotomous key.
Earth Science 2: Introduction to Tectonics: (pre-req for this module) A review of the earth’s internal structure and the
formation of continents as a result of plate movement. The types of faults are defined and modeled with sponges and
clay.
Earth Science 15: Seismic Waves - An introduction to the concept that S- and P-waves travel at different speeds
away from the epicenter of an earthquake. Students use triangulation to locate the epicenter of a theoretical
earthquake.
Engineering 7: Earthquake-Resistant Buildings: Using the problem of earthquake-resistant building design, this
module focuses on steps 5 and 6 of the engineering design process: constructing a prototype and testing the
solution(s).
This lesson would also work well in relation to Chemistry, in particular:
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Chemistry 14: Viscosity – Students investigate viscosity by using falling sphere viscometers to examine the speed at
which a marble drops through tubes of liquids with varying viscosities.
For other module sequences and groups, look here: www.sciencefromscientists.org/sequences
Standards Covered:
Please click the following link to our website to review the standards covered by this lesson, listed by state:
http://www.sciencefromscientists.org/standards/
Lessons are matched to both national NGSS and local state standards.
Classroom Post and Activities:
A link to the Follow Up Student activity can be found in the Classroom Post on our website at
sciencefromscientists.org/cohorts. Use the name of your school/cohort and password to log in. The follow-up activity
invites the students to model tectonic plates and the asthenosphere with whipped topping and graham crackers.
Additional Resources:
WGBH Videos and Activities: The PBS educational site is a great, free resource for educators but you must create an
account to use the materials. The first time you log in to the PBS Learning Media website you will be asked to create an
account and provide an email and password. Once you have logged in, select “keep me logged in” to avoid having to
repeat the process.
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A two-day lesson plan on plate tectonics by PBS Digital Media:
http://mass.pbslearningmedia.org/resource/ess05.sci.ess.earthsys.lp_platetectonics/plate-tectonics/
Science from Scientists
617-314-7773 • [email protected] • www.sciencefromscientists.org
Copyright © 2016 Science from Scientists
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Plate Tectonics: An introduction (video):
http://mass.pbslearningmedia.org/resource/ess05.sci.ess.earthsys.plateintro/plate-tectonics-an-introduction/
Dynamic Earth interactive: http://mass.pbslearningmedia.org/resource/fe7ae96f-b758-49bc-8da67b912892e484/fe7ae96f-b758-49bc-8da6-7b912892e484/
Asthenosphere: Using Silly Putty as an Analogy (video):
http://www.iris.edu/hq/inclass/video/asthenosphere_using_silly_putty_as_an_analogy
Lesson on Viscoelasticity: (copy/paste link) https://www.teachengineering.org/lessons/view/cub_surg_lesson04
Science from Scientists
617-314-7773 • [email protected] • www.sciencefromscientists.org
Copyright © 2016 Science from Scientists
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