Being P-Waves and S-Waves
Michelle Hall-Wallace (Science Education Solutions, Inc.) and Randall Richardson (University of Arizona, Tucson)
This material was originally created for
Starting Point:Introductory Geology and is replicated here as part of the
SERC Pedagogic Service.
This activity was selected for the On the Cutting Edge Exemplary Teaching Collection
Resources in this top level collection a) must have scored Exemplary or Very Good in all five review categories, and must also rate as "Exemplary" in at least three of the five categories. The five categories included in the peer review process are
- Scientific Accuracy
- Alignment of Learning Goals, Activities, and Assessments
- Pedagogic Effectiveness
- Robustness (usability and dependability of all components)
- Completeness of the ActivitySheet web page
For more information about the peer review process itself, please see https://serc.carleton.edu/teachearth/activity_review.html.
This resource received an Accept or Accept with minor revisions rating from a Panel Peer Review process
These materials were reviewed using face-to-face NSF-style review panel of
geoscience and geoscience education experts to review groups of resources addressing
a single theme. Panelists wrote reviews that addressed the criteria:
- scientific accuracy and currency
- usability and
- pedagogical effectiveness
Reviewers rated the resources:
- Accept
- Accept with minor revisions
- Accept with major revisions, or
- Reject.
They also singled out those resources they considered particularly exemplary, which are given a gold star rating.
Following the panel meetings, the conveners wrote summaries of the panel discussion for each resource; these were
transmitted to the creator, along with anonymous versions of the reviews.
Relatively few resources were accepted as is. In most cases, the majority of the resources were either designated as 1) Reject or 2) Accept with major revisions.
Resources were most often rejected for their lack of completeness to be used in a classroom or they contained scientific inaccuracies.
- First Publication: August 10, 2006
- Reviewed: October 31, 2012 -- Reviewed by the On the Cutting Edge Activity Review Process
Summary
Modeling P-waves and S-Waves
Have the students get out of their chairs, move into groups of 10-15 in an area where they can stand together in a line standing shoulder to shoulder within their group with their arms across each-other's shoulders. For a P-wave, push the group from one end of the line. All the students will bend, but straighten. For an S-wave, have the person at the end of the line bend at the waist to almost a 90-degree angle and then to stand up straight again. This will force the next person, and then the next person, and so on to do the same.
An alternative way to do this activity is to have the whole class stand up together in a circle and do "the wave" as they would in a football stadium, raising their arms and lowering them as the next person raises his or hers. This is a transverse (S) wave. Then have them do a longitudinal (P) wave by having them gently grip each other's shoulders and having one pull or push the next person in line.
Rates and Reflection
Have student from outside the group measure how long it takes the given wave to propagate, and others to measure the distance. Explain that the time is the period and the distance is the wavelength. What are the frequency and the velocity of the wave? Can the students making the wave speed it up?
You may also want to designate a student in the middle of a chain or move the chain against a rigid surface like a wall to reflect waves. Instead of the wave continuing beyond the point of reflection, it must go back the way it came.
Topics
Geophysics,
Physics Grade Level
College Introductory
Follow the links above to find
activities from Teach the Earth on a specific topic.
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Learning Goals
These exercises will:
- Help students develop a good understanding of different kinds of seismic waves and their effects
- Liven up a lecture class (esp. for 8 AM sections)
- Demonstrate a quantitative idea (wave frequency)
Context for Use
These exercises will work well even in large classes.
Description and Teaching Materials
All you need is room for the students to stand up (often at the edge of a classroom or just outside).
Teaching Notes and Tips
These exercises are short (less than half an hour) and require no materials. Michelle Hall-Wallace suggests having one group model the activity first while the others watch and learn. Students may need reminding to stand with their feet firmly planted and not to push too hard or too suddenly.
Assessment
Informal. Ask students how the direction of motion corresponds to the direction of wave propagation for the P-wave (parallel) and the S-wave (perpendicular). Additionally, make sure they estimate frequency and velocity.
References and Resources
This exercise is developed from (
Hall-Wallace, 2000 ) and (
Richardson, 2000 ).
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