Download 9-26 Review SFS and CD.notebook

9­26 Review SFS and CD.notebook
October 04, 2011
Good Morning!
October 4, 2011
1. Please paste your Science
Energizer slip into your journal!
2. Answer the question and explain
WHY you chose your answer.
Mary decides to conduct a study of local weather patterns
for school. Mary's teacher wants her to turn in detailed and
accurate notes as well as her results and conclusion. Why
would it be important to include Mary's notes?
A. The conclusion of Mary's study will not make sense
without the notes.
B. Mary's teacher can use the notes to examine Mary's
knowledge of the local weather patterns.
C. The notes provide a way to understand Mary's
hypothesis.
D. Mary's teacher needs the notes to make sure Mary's
study was conducted following the scientific method.
1
9­26 Review SFS and CD.notebook
October 04, 2011
Current Events in Science
Each group will read an
article, answer
questions, and then
share with the class.
1. First, read individually.
2. Answer the questions.
3. Collaborate with your team.
Be prepared
to share!
Class Discussion
Article 1 you lead. Select a person to
be the spokesperson. This person will
talk about the 2 sentences summary
and their questions with answers.
While they are talking,
listening carefully and fill in
the answer the questions
from each article.
You will turn it in when you're
done. This will be a grade.
2
9­26 Review SFS and CD.notebook
October 04, 2011
Reviewing Continental Drift and Sea-Floor Spreading
1. Get out your notes for Continental
Drift and Sea-Floor Spreading.
2. Turn your listening ears on!
3. Ask questions if you are confused.
Alfred Wegener's
hypothesis was that all
the continents were once
joined together in a
single landmass and have
since drifted apart.
continental drift-the hypothesis
that the continents slowly move
across Earth's surface.
3
9­26 Review SFS and CD.notebook
October 04, 2011
Evidence from Land Features
When he pieced
together maps of
Africa and South
America, he
noticed that
mountain ranges on
both continents
line up.
He also noticed that coal
fields in Europe matched
up with similar ones in
North America.
Evidence from Fossils
An example is Glossopteris,
a fernlike plant that lived
250 million years ago.
These fossils have been
found in rocks in Africa,
South America, Australia,
India, and Antarctica.
4
9­26 Review SFS and CD.notebook
October 04, 2011
Other fossil examples include the
fresh water reptiles Mesosaurus
and Lystrosaurus.
These fossils were found in areas
that are now separated by oceans
and neither could have swum great
distances across salt water.
Wegener inferred that these
reptiles had to have lived on one
large land mass.
Evidence from Climate
As a continent moves closer to
the equator it becomes hotter
and as it moves away, colder.
But continents carry with them
the fossils and rocks formed at
the previous locations.
5
9­26 Review SFS and CD.notebook
October 04, 2011
Deep scratches in rocks
showed that continental
glaciers once covered South
Africa.
The climate of South Africa
is too mild today for
continental glaciers to form.
Wegener concluded that
when Pangaea existed, South
Africa was much closer to
the South Pole.
mid-ocean ridge
an undersea
mountain chain
where new ocean
floor is produced,
it is a divergent
plate boundary
divergent boundary
a plate boundary
where two plates
move away from
each other
6
9­26 Review SFS and CD.notebook
October 04, 2011
Harry Hess proposed in 1960 that the movement of the
continents was a result of sea-floor spreading.
Sea-floor spreading
• The sea floor spreads apart along both sides of
a mid-ocean ridge as new crust is added
• As a result, the ocean floors move like conveyor
belts, carrying the continents along with them
7
9­26 Review SFS and CD.notebook
October 04, 2011
1. Sea-floor spreading
begins at a mid-ocean
ridge, which forms
along a crack in the
ocean crust.
2. Along the ridge, molten material that
forms several kilometers beneath the
surface rises and erupts.
3. At the same
time, older rock
moves outward
on both sides of
the ridge.
4. As the molten material cools,
it forms a strip of solid rock in
the center of the ridge.
5. When more molten material
flows into the crack, it forms
a new strip of rock.
8
9­26 Review SFS and CD.notebook
October 04, 2011
What are the pieces of evidence for SeaFloor Spreading?
1. Molten Material
2. Magnetic Stripes
3. Drilling Samples
Evidence from Molten Material
Scientists found rocks that were shaped like pillows or
like toothpaste squeezed from a tube.
These rocks only form when molten material hardens
quickly after erupting under water.
These rocks
showed that
molten material
has erupted
again and again
along the midocean ridge.
9
9­26 Review SFS and CD.notebook
October 04, 2011
Evidence from Magnetic Stripes
Earth's magnetic poles have
reversed themselves many
times during Earth's history.
Scientists discovered that
the rock that makes up the
ocean floor lies in a pattern
of magnetized stripes.
The stripes hold a
record of reversals
in Earth's magnetic
field.
Evidence from Drilling Samples
Rock samples were
collected in 1968 from a
drilling ship called the
Glomar Challenger.
Scientists determined the age of the rocks and
they found that the farther away from a ridge the
samples were taken, the older the rocks were.
The youngest rocks were always in the center of
the ridges.
10
9­26 Review SFS and CD.notebook
October 04, 2011
If new oceanic lithosphere is created at mid-ocean ridges, where does it go?
Subduction
when oceanic crust sinks
beneath a deep-ocean trench
and back into the mantle at a
convergent plate boundary
Continental Drift
Sea-Floor Spreading
11
9­26 Review SFS and CD.notebook
October 04, 2011
Continental Drift
Sea-floor Spreading
12
9­26 Review SFS and CD.notebook
October 04, 2011
13