Earth’s History

Earth’s HistoryMs. Yewande 8th Grade Science

Warm-up:Write questions and answers in notebook.

1. What is the first thing a student should do if an accident happens during a science experiment?A. Report to the teacherB. Clean the laboratory stationC. Locate the nearest exitD. Put on safety goggles

Warm-up:Write questions and answers in notebook.

1. Which device is used to determine the volume of a liquid?A. AnemometerB. Graduated cylinderC. Test tubeD. Thermometer

Lab Safety

Safety Rules: 1. Always wear safety goggles whenever you are working with chemicals

or other substances that might get into your eyes.2. Never reach across a flame.3. Immediately notify your teacher if any chemical gets on your skin or

clothing to find out what to do to clean it off.4. Never look directly into a test tube when mixing or heating chemicals. 5. Always point a test tube away from you and others when heating it

over a flame or other heat source.

Lab SafetySafety Rules:

1. Never smell a chemical directly from the container. Wave your hand over the opening of the container and “waft” the fumes towards your nose.

2. Never taste a chemical unless you are instructed by your teacher to do so.3. Always clean up your work area and equipment after an experiment is

completed. Equipment must be returned to its proper place.4. Read and follow all directions exactly as they are written. If in doubt, ask

your teacher for help! 5. Never mix chemicals (or perform tests) without your teacher’s permission.

Lab Safety

Safety Rules: 1. Never mix chemicals without your teacher’s permission. 2. Never run (or push someone else) in the lab. ( this rule applies

at all times!)3. Keep lids on bottles and containers when not in use.4. Never use broken or chipped glassware.5. Keep your work area clean and keep all materials (clothing, hair,

papers, etc.) away from a flame or heat source.

Lab Safety

Safety Rules: 1. Always clean up your work area and equipment after an

experiment is completed Equipment must be returned to its proper place.

2. Immediately notify your teacher if you get cut or have another injury when performing an experiment.

3. Wash your hands before and after each experiment.

Classwork

• Complete the classwork in notebooks

Lesson

• November 4, 2013

Plate Tectonics

Earth’s LayersThe Earth's rocky outer crust solidified billions of years ago, soon after the Earth formed.

This crust is not a solid shell; it is broken up into huge, thick plates that drift atop the soft, underlying mantle.

The Crust

• Outermost layer• 5 – 100 km thick• Made of Oxygen, Silicon, Aluminum

The Mantle• Layer of Earth between

the crust and the core• Contains most of the

Earth’s mass• Has more magnesium

and less aluminum and silicon than the crust

• Is denser than the crust

The Core• Below the mantle

and to the center of the Earth

• Believed to be mostly Iron, smaller amounts of Nickel, almost no Oxygen, Silicon, Aluminum, or Magnesium

Tectonic Plates

Plate Tectonics

• Greek – “tektonikos” of a builder• Pieces of the lithosphere that move around• Each plate has a name• Fit together like jigsaw puzzles• Float on top of mantle similar to ice cubes

in a bowl of water

Continental Drift

http://members.enchantedlearning.com/subjects/astronomy/planets/earth/Continents.shtml

Alfred Wegener 1900’sContinents were once a single land mass that drifted apart.

Fossils of the same plants and animals are found on different continents

Called this supercontinent Pangea, Greek for “all Earth”

245 Million years ago

Split again – Laurasia & Gondwana 180 million years ago

Evidence of Pangea

Sea Floor Spreading

Sea Floor Spreading

• Mid Ocean Ridges – underwater mountain chains that run through the Earth’s Basins

• Magma rises to the surface and solidifies and new crust forms

• Older Crust is pushedfarther away from the ridge

How Plates Move

http://pubs.usgs.gov/gip/dynamic/unanswered.html

Different Types of Boundaries

http://pubs.usgs.gov/gip/dynamic/understanding.html

Divergent Boundary – Arabian and African Plates

Arabian Plate

African PlateRed Sea

Divergent Boundary – Iceland

http://pubs.usgs.gov/gip/dynamic/understanding.html

Divergent Boundary - Oceanic

http://www.geology.com

Divergent Boundary - Continental

http://www.geology.com

Convergent Boundary – Indian and Eurasian Plates

Indian Plate

Eurasian Plate

Convergent Boundary – Oceanic & Continental

http://pubs.usgs.gov/gip/dynamic/understanding.html & http://www.geology.com

Convergent Boundary – Oceanic & Oceanic

http://pubs.usgs.gov/gip/dynamic/understanding.html & http://www.geology.com

NOTE – PLATES ARE REVERSED

Convergent Boundaries - Continental

http://pubs.usgs.gov/gip/dynamic/understanding.html & http://www.geology.com

Transform Boundary – San Andreas Fault

www.geology.com

Review

• Name the 3 main layers of the Earth• What is a tectonic plate?• What was Pangea?• What is Sea-Floor spreading?• Name the three different types of plate boundaries and one

location on Earth for each one