welcome to science 9/13

On your paper, answer the following question of the day: In the Liquid Layers Lab, the coldest liquid was the

most dense. In class you learned that the core is the most dense as well as hottest layer of Earth. Typically the colder a substance, the more dense it is. Why do you think the core is so hot yet is still the most dense layer.

Today’s Schedule1. ? Of the Day

2. Review Liquid Layers Lab3. Reconstructing Pangaea Lab

What was Pangaea?What was Pangaea?•Has the world always looked as it does today?•Continents of the Past. Animation.

What was Pangaea?What was Pangaea?•Pangaea means ‘all

land’ in Greek•245 million years ago

Earth’s continents were joined together to form a supercontinent known as Pangaea.

Reconstructing Pagaea LabReconstructing Pagaea Lab•1. Label the 7 continents, including Greenland

and India, before cutting them out. •2. Outline the edge of each continent with a

different color.•3. When you are cutting, cut as close to the

edge of the continents as possible. Don’t cut out the islands.

•4. Ask Questions if you are confused or need help.

•5. Follow the procedure on the Lab Sheet.

Welcome to Science 9/14

•Immediately find your partner for the Reconstructing Pangaea Lab and continue working on it. You have about 20 minutes to complete the lab.

•Today’s Schedule•1. Conclude Pangaea Lab•2. Begin Ch. 7 Section 2 Notes/Discussion

Evidence from Mountains

Evidence from Glaciers

•Question of the Day•Besides the shape of the continents, what

other evidence shown in the map below supports the Pangaea theory?

Ch. 7 Section 2 Restless Restless ContinentsContinents•What do we mean when we say Restless Restless

ContinentsContinents?•Continental drift- theory that continents can

drift apart and have done so in the past.

I. Drifting ContinentsI. Drifting Continents

•Why did Alfred Wegener believe in continental drift?

•1. continents fit together like a puzzle•2. Fossils of the same species were found on

different continents•3. evidence of rocks and climatic conditions

were found on the same continents.

II. Breakup of PangaeaII. Breakup of Pangaea•What did Wegener infer based on his evidence? •Millions of years ago there was one

supercontinent that over time slowly broke apart

III. Wegener’s Theory III. Wegener’s Theory RejectedRejected

•Why?•Wegener could not conclude how or why the

continents moved.•What discovery provided clues that Wegener

was right?

III. Mid-Ocean RidgeIII. Mid-Ocean Ridge•1960’s underwater worldwide mountain chain

was discovered

•What happens at the mid-ocean ridge that moves the continents?

•Sea-floor spreading

III. What is sea-floor III. What is sea-floor spreading?spreading?

•As plates diverge magma rises up to form a mid-ocean ridge. As more magma continues to rise and harden it spreads the sea-floor apart .

•animation

III. Evidence of Sea-floor III. Evidence of Sea-floor SpreadingSpreading•How do we know sea-floor spreading is

happening? Seafloor Spreading Interactive

•Rock samples taken from the sea-floor show that the oldest rocks are further from mid-ocean ridges.

IV. Magnetic ReversalsIV. Magnetic Reversals•Throughout history Earth’s magnetic fields will

switch. Meaning the north pole goes to the south pole and vice versa.

•Magnetic minerals in magma align with Earth’s magnetic field. When the poles switch this creates stripes or bands that can be seen on the sea-floor.

•animation