Transcript Rocks Get Stressed 10/9/09

Rocks Get Stressed 10/12/15
7-4a pg. 181
IN:
How do you think this
mountain was created?
Cause of changes in rocks.
– amount of force per
unit area that is put on a given
material.
 Stress
Stress and Rocks
– when rock layers
change their shape due to stress.
 Deformation
Two types:
1.Elastic
2.Plastic
What is deformation?
 Elastic-
 Return to their original shape after
the stress is removed.
What is deformation?
 Plastic-
 Once stress is removed, the deformation
remains.
The Sinai Massif
 Once
this limit is passed, the rock will
break – fault is produced.
Types of Stress
Compression
 Tension
 Shearing

What is compression?
– type of stress that
occurs when an object is squeezed.
 Compression
What is tension?
– the type of stress that
occurs when forces act to stretch an
object.
 Tension
What is shearing?
– type of stress that occurs
when objects slide opposite each
other.
 Shearing
Animation of stress

http://scign.jpl.nasa.gov/learn/plate5.htm
OUT:
Summarize the 3
types of rock stress.
(You can do this in 7 words)