Author: Stephen Hajosy
Title: SEISing up an Earthquake
Discipline: Science
Grade Level: 8
Estimated Time: (2-3 50 minute lessons)
Lesson Overview:
Although students at this level already understand that earthquakes exist and that they can have a catastrophic
effect on our lives, this is the first time they are introduced to the tools with which seismologists use to study
these natural phenomena. The students will explore the concepts of seismic waves (primary, secondary, and
surface). This lesson incorporates a discussion of some of the basic properties of waves (more fully developed
under standard 8-6.3). Using a computer generated simulation the students will also develop and understanding
of how scientists are able to determine the location (epicenter) and intensity of an earthquake. An extension
activity, Building Your Own Seismograph, will allow the students to gain a more practical feel for how
scientists are able to measure earthquakes in the real world.
Essential Question: How do scientists (seismologists) determine the strength and location of earthquakes?
SC Science Standards (2005)
8-3.2 Explain how scientists use seismic waves – primary, secondary, and surface waves – and Earth’s
magnetic fields to determine the internal structure of Earth. Taxonomy level: 2.7-B Understand
Conceptual Knowledge
8-3.3 Infer an earthquake’s epicenter from seismographic data. Taxonomy level: 2.5-B Understand
Conceptual Knowledge
8-1.3 Construct explanations and conclusions from interpretations of data obtained during a controlled
scientific investigation.
Prerequisite knowledge:
Plate tectonic theory is an important concept in that it describes the source of energy responsible for
earthquakes. A discussion of the properties of waves (longitudinal vs. transverse) is embedded throughout the
lesson. The idea that energy, not matter, is transferred as waves propagate through matter is essential for the
students to understand.
Teacher Background Support Information:
Seismographs are the essential tool used by scientists to measure the wave energy created by earthquakes as a
result of plate tectonic interactions. The waves generated come in three basic categories. Primary (P) waves are
longitudinal and travel the fastest through the earth. Secondary (S) waves are transverse. They travel slower
than P waves and can only be transmitted through solid earth. Finally, surface waves are formed when the P
and S waves reach the surface of the earth. It is the surface waves that are responsible for the effects we feel on
the surface and which give earthquakes their destructive force. The relative speed difference (between the P
and S waves) is what scientists use to determine the epicenter of an earthquake.
Materials:
 Earthquake – Recording Station (Student exploration activity) (retrieved from:
http://www.explorelearning.com/index.cfm?method=cResource.dspDetail&ResourceID=367
 Earthquake – Determination of Epicenter (Student exploration activity) (retrieved from:
http://www.explorelearning.com/index.cfm?method=cResource.dspDetail&ResourceID=371
 UPSeis – An educational site for budding seismologists (retrieved from:
http://www.geo.mtu.edu/UPSeis/waves.html
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U.S. Geological Society Photographic Library (retrieved from: http://libraryphoto.cr.usgs.gov/cgibin/show_picture.cgi?ID=ID. Hillers, J.K.)
Homemade Seismograph (retrieved from: http://cse.ssl.berkeley.edu/img/earthquakes/MkSeismograph)
Slinky(s)
ENGAGE:
Estimated Time: [10 minutes]
Sub Components: [Prior knowledge, Misconceptions, Develop scientific question, Motivation/interest]
Representative Questions:
Where did this photo take place? When? What caused the train to derail?
Description:
On Aug 31, 1886 one of the strongest earthquakes in U.S. history was centered on Charleston, SC. It is
estimated that 60 people died, 14,000 houses lost their chimneys, and the region suffered up to $23 million
worth of damage (http://earthquake.usgs.gov/earthquakes/states/south_carolina/history.php).
As students enter the classroom they will have a chance to infer what may have happened to cause the train to
derail as shown in the photo taken following the Charleston earthquake.
Formative Assessment:
Conduct a KWL (KW portion) exercise with the whole class. “How does an earthquake cause damage?” would
be a good central question. Record student inputs for all to see. This can be a great place to add key vocabulary
and concepts as the inquiry progresses.
Teacher Reflection:
Do the students have any understanding of wave properties? This will help determine how to conduct the
EXPLORE -1.
PROCEED, CLARIFY, OR REMEDIATE?
EXPLORE 1 Estimated Time: [15 Minutes]
Sub Components: [Interpret, Evidence, Communicate, Alt Explanations, Justify]
Representative Questions:
 What is a wave?
 Is matter transported as a result of wave energy?
 Where else in your daily life do you experience wave phenomena?
Description:
There are two primary demos which should keep the students interested and foster an understanding of the
fundamental difference between transverse and longitudinal waves (both which occur as a result of
earthquakes). The teacher may use one or both.
1.
Slinky Exploration: have the students create transverse (snakelike) and longitudinal (compression)
waves with their slinky. This can be done in small groups or as a teacher demo. Does matter travel
along with the wave?
2. Human chain: Have a group of students (5-10) stand in a line, shoulder to shoulder, with their arms
interlocking across their shoulders. The teacher can demonstrate a longitudinal wave by pushing or
pulling at one end of the group. The transverse wave can be demonstrated by having the lead student
bend over at the waist, then stand straight, bend over, stand straight, etc. Once again, did the students
see a transport of matter (human flesh) as the wave propagated?
Formative Assessment:
What is the difference between the two types of wave we just saw? How are they alike, different?
Teacher Reflection:
Do student responses indicate understanding of different types of waves? Did all students actively participate in
the exploration?
PROCEED, CLARIFY, REMEDIATE, OR RE-ENGAGE?
EXPLAIN 1
Estimated Time: [15 minutes]
Sub Components: [Analyze, Communicate]
Representative Questions:
 How do you think what we just learned applies to the science of earthquakes.
 What do we call the different types of wave?
Description:
This is a teacher led discussion utilizing probing questions. Before this portion distribute the Earthquake
vocabulary sheet included on the Explore Learning website. This will be useful for their next exploration.
Also, display “UPSeis” website. Provide the students with the visual simulations of P, S, and Surface waves
found on this website. Don’t forget to reemphasize how matter is not transported during wave propagation.
These simulations are excellent for this purpose as well.
Formative Assessment:
Have students turn their vocabulary sheets face down and see if they can match vocabulary with the appropriate
definition as prompted by the teacher. Take only a few minutes for this.
Teacher Reflection:
Did the simulations of P, S and Surface waves confuse or reinforce the concepts of transverse and longitudinal
waves from the previous demos?
Ability to analyze the quality of exploration conducted?
PROCEED, RE-ENGAGE, REMEDIATE, OR HAVE STUDENTS CLARIFY?
EXPLORE-2 Estimated Time: [40 minutes]
Sub Components: [Test and Collect]
Representative Questions:
How do scientists measure earthquakes?
Description:
The students will utilize the Explore Learning computer simulations (“Earthquake – Recording Station Gizmo”
& “Earthquake – Determination of an Epicenter Gizmo”) for this exploration. There are three options for this
portion of the inquiry. The teacher can lead them through the exploration as a group (while students record
individually) or they can perform the exploration in small groups if computer resources are available. A final
option would be to do this at home. It is a self guided exploration. In the “Recording Station” the students will
develop their own data which demonstrates a linear relationship between the time difference (between arrival of
P and S seismic waves) and the distance from the epicenter. The students should discover that the P-S time
difference (in seconds) is roughly 1/8 of the distance (in km) from the epicenter. (i.e. a time difference of 10
seconds would correspond to a distance of 80 km). In the “Determination of an Epicenter” the students will
continue the exploration to determine the location of an earthquake’s source using the principle of triangulation.
They will need their data from the “Recording Station” to accomplish this.
Formative Assessment:
Students will present graphical data
Teacher Reflection:
Meaningfulness of data collected? How organized?
PROCEED; CLARIFY; REMEDIATE; OR RE-ENGAGE?
EXPLAIN
Estimated Time: [15 minutes]
Sub Components: [Interpret, Evidence, Communicate, Alt Explanations, Justify]
Representative Questions:
 What took place?
 What surprised you? What is still confusing?
 What do you have to say about the quality of your experiment?
 How has the time difference between arrival of P and S waves allowed seismologists to
distance from an earthquake? What is the importance of triangulation?
determine
Description:
This class discussion will focus on the data and graphs produced by the students. The linear relationship
between distance and time difference is an important concept to emphasize. What’s more, it’s an excellent way
to foster a connection to math, especially for 8th graders who are at the pre-algebra stage of mathematical
reasoning.
Formative Assessment:
The simulations each have a nice set of assessment questions to complete at the end of each exploration. Also,
the teacher should complete the L portion of the KWL chart begun during the early stage of this inquiry.
Teacher Reflection:
Effectiveness of communicating knowledge? Ability to analyze the quality of exploration conducted? Were
there any concepts (i.e. wave properties) which proved difficult for the students to grasp?
PROCEED; CLARIFY; REMEDIATE; OR RE-ENGAGE?
EXTEND Estimated Time: [20 minutes]
Sub Components: [apply, elaborate, transfer, generalize]
Representative Questions:
 What technology enables scientists and industry to gather pertinent seismic data?
 What industries may be able to utilize the knowledge of seismologists? (i.e. natural resource
exploration)
 Are there any other devices you use in your everyday life that utilize this concept of triangulation? (i.e.
GPS receivers)
Description:
Seismographs are the tools of the trade for scientists trying to discover more about not only earthquakes, but
also the composition of the earth beneath our feet. They provide useful data to help industries, such as mining
and energy exploration (i.e. natural gas), as well as help scientists better understand the magnetic field of the
earth. Using a homemade seismograph (like the one found at…
http://cse.ssl.berkeley.edu/lessons/indiv/davis/hs/Seismograph.html) would be an excellent way for students
to extend their knowledge to the real world geological science. This device would most likely need to be
constructed by the teacher in advance but it would not take much time or money. The students could then
produce their own seismographs in the classroom.
Formative Assessment:
Journal entry
Teacher Reflection:
Quality and number of applications made?
Ability to elaborate on ideas/concepts?
Competency and accuracy generalizing experience?
DEBRIEF; RE-ENGAGE; RE-EXPLORE; HAVE STUDENTS CLARIFY; ANOTHER EXTENSION?
Technology and Resources
Earthquake in Charleston, SC; Aug 31, 1886
(ENGAGE)
Seismograph Explorations
(EXPLORE)
P, S, and Surface Waves (Simulation)
(EXPLAIN)
Homemade Seismograph
(EXTEND)