b. If it does, calculate how far down the paper stack to place your
individual marker, then come forward to place it at the correct depth.
c. If it does not, use the math we have already done to calculate how
much more paper would be needed. Share your findings with the class.
6. Elicit ideas from the class on the age of the Earth. (The answer,
about 4.54 billion years, is on Master 2.3c.) Ask: How many reams of
paper like the ones in the front of the classroom would it take to
represent that many years? (46 reams)
C. Conclusion
Ask the class: Now that you have an idea of the age of the Earth,
would you describe the human race as young or old? (relatively
young) Which occurred more recently, the extinction of the dinosaurs
or the appearance of human beings? (the appearance of humans)
Compare these facts with the students’ earlier guesses. Emphasize that
terms like young and old, long ago and recent can have very different
meanings in different contexts. Because an event such as an
earthquake has not taken place in historical time does not mean it is
impossible, given the great sweep or geological time.
TEACHING CLUES AND CUES
The two parts of this
activity use the same
materials and take
approximately the same
ACTIVITY TWO
P
ALEOSEISMOLOGY
,
OR
R
EADING THE
C
LUES
RA T I ONA L E
By using models, students will learn how geologists apply present
knowledge to understand seismic history.
F OCU S QU E S T I ON S
How do we know about earthquakes that happened long ago?
OB J E C T I V E S
Students will:
1. State and explain several basic geologic principles.
2. Model the procedure geologists use to determine earthquake
recurrence intervals.
length of time. It may be convenient
to do them in sequence. Alterna-
tively, you may want to have half the
class do the first activity and the rest
do the second.
MA T E R I A L S
Q
Transparencies made from Master 2.3d, Sag Pond, 1830 to 1994
Q
Overhead projector
Q
Newspapers for covering desks
Q
Play clay or modeling clay, in red, blue, yellow, and white
Q
Student copies of Master 2.3e, Sag Pond Template
Q
15-cm (6-in) lengths of dowel or other small cylinders for rolling
play dough (
optional
)
Q
Knives for cutting the clay (Plastic picnic knives will do.)
A G U
/
F E M A
69
S
E I S M I C
S
L E U T H S
