Why was Wegener´s hypothesis rejected? Warm Up! Why was Wegener´s hypothesis rejected?

Why was Wegener´s hypothesis rejected? Warm Up! Why was Wegener´s hypothesis rejected? He could not explain what was pushing or pulling the continents

S4 - Sea-Floor Spreading Big book pgs. 141-147 Small book pgs. 23-29

Was Wegener Right? In the 1950s, scientists used sonar to find the mid-ocean ridge.

Was Wegener Right? In the 1950s, scientists used sonar to find the mid-ocean ridge.

Was Wegener Right? In the 1950s, scientists used sonar to find the mid-ocean ridge.

Sonar

Mid-Ocean Ridge

Harry Hess American Scientist, studied Mid Ocean Ridge Said ocean floors move like conveyor belts. As the ocean floor moves, they carry the continents with them

Harry Hess American Scientist, studied Mid Ocean Ridge Said ocean floors move like conveyor belts. As the ocean floor moves, they carry the continents with them

Mid-Ocean Ridge

TO DO From Section 4: Sea-Floor Spreading define the following key terms: Mid-ocean ridge Sonar Sea-floor spreading Deep-ocean trench Subduction *Use glossary in back of book to help you

Warm Up! Continue defining the following key terms: Mid-ocean ridge Sonar Sea-floor spreading Deep-ocean trench Subduction *Use glossary in back of book to help you

What is Sea Floor Spreading? Magma rises from the mantle and erupts through the Mid Ocean Ridge. The magma pushes older rocks away on both sides of the ridge.

What is Sea Floor Spreading? New crust is being created at the Mid Ocean Ridge

The new crust pushes older crust away on both sides of the ridge.

Evidence 1. Evidence from molten material (magma) 2. Evidence from magnetic stripes 3. Evidence from drilling samples Not necessary to copy

1. Evidence from Molten Material Rocks found that form when magma and water mix

1. Evidence from Molten Material Rocks found that form when magma and water mix

2. Evidence from Magnetic Stripes Pattern in rock shows that iron faces different directions

2. Evidence from Magnetic Stripes Pattern in rock shows that iron faces different directions

Evidence from Magnetic Stripes When Earth’s magnetic field pointed north, the iron in the magma that erupted into the ocean faced north as it hardened. When Earth’s magnetic field reversed, the iron faced south. The magnetic field reversed again. This formed stripes.

3. Evidence from Drilling Samples Newer rock is found near the Mid Ocean Ridge.

3. Evidence form Drilling Samples Newer rock is found near the Mid Ocean Ridge.

To do S4 Assessment Big Book pg. 147 #1,2 Small book pg. 29 #1,2

Warm Up! Who proposed the idea of Sea Floor Spreading?

Warm Up! Who proposed the idea of Sea Floor Spreading? Harry Hess, an American scientist purposed the idea in 1960

What is Sea Floor Spreading?

The new crust pushes older crust away on both sides of the ridge. What is Sea Floor Spreading? The new crust pushes older crust away on both sides of the ridge.

The new crust pushes older crust away on both sides of the ridge. What is Sea Floor Spreading? The new crust pushes older crust away on both sides of the ridge.

Subduction Part of the ocean floor sinks back to the mantle at the deep ocean trench

Subduction Part of the ocean floor sinks back to the mantle at the deep ocean trench

Open Textbooks to: Big book, pg. 148 Small book pg. 30

Modeling Sea Floor Spreading Big book, pg. 148 -149 Small book pg. 30 -31 Can work alone or with a partner (group of 2 for 1 model max) Follow directions under Procedure 3. When finished, Put your names on the model and turn in to back table 5. Complete Section 4 Assessment in Science notebook (Due Friday) 6. Work on Math Packet (Fractions)