EARTHS LAYERS ARIZONA STATE SCIENCE STANDARDS GRADE LEVEL

EARTH’S LAYERS ARIZONA STATE SCIENCE STANDARDS: GRADE LEVEL 7 Strand 6: Earth and Space Science Concept 2: Earth’s Processes and Systems • Understand the processes acting on the Earth and their interaction with the Earth systems. PO 3. Analyze the evidence that lithospheric plate movements occur. PO 4. Explain lithospheric plate movement as a result of convection.

EARTH’S LAYERS DAILY OBJECTIVE: Students will be able to recognize and name layers of the Earth

ORIGIN OF THE EARTH • Meteors and Asteroids bombarded the Earth is 4. 6 billion years old

TYPES OF EVIDENCE: Collecting data by measuring seismic waves created by earthquakes from around the world.

EVIDENCE OF INTERNAL STRUCTURE • Density – calculate density of Earth – Speculate on probable compositions • Meteorites – Use composition and age to determine composition and age of Earth • Seismic waves – Travel times and direction give indication of internal structure of Earth Granite Basalt

SEISMIC WAVE • Vibrations that travel through Earth carrying the energy released during an earthquake

TYPES OF SEISMIC WAVES • P waves – Primary waves – Push and pull movement – Travel fastest (~ 6 km/sec) – Travel thru solids and liquids • S waves – Secondary waves – Move side-to-side – Slower (~ 4 km/sec) – Travel thru solids only

SEISMIC WAVES THROUGH EARTH

TYPES OF EVIDENCE: Collecting data by examining rock samples driven to the surface of the Earth.

LAYERS OF THE EARTH: CRUST v. Layer of rock that form Earth’s outer skin v. Thinnest layer of Earth, and least dense v. Includes land forms, soil, water, all life on earth

TWO TYPES OF CRUST ²Oceanic: made of basalt. All of the ocean floors ²Continental: made of granite. Includes all continents and islands

LAYERS OF THE EARTH: MANTLE v Layer of hot, solid rock just below the Earth’s crust v Thickest layer of Earth, and more dense than the crust v Two kinds: v. Lithosphere v. Asthenosphere

TYPES OF MANTLE Lithosphere ²Rigid layer of the upper most part of the mantle and lower part of the crust ²Made up of large and small slabs of tectonic plates

TYPES OF MANTLE Asthenosphere ²Under the lithosphere ²Softer and hotter rock is located here ²Flows slowly like hot tar

EARTH’S INTERIOR • “Litho” comes from the Greek word meaning rock • Asthenosphere – the slushy (partially liquid & solid) in the upper mantle on which the plates “float” • “Asthenes” comes from the Greek word meaning weak • Sphere is the shape of the Earth

LAYERS OF THE EARTH: OUTER CORE ØComposed of liquid iron and nickel ØTemperature, pressure, and density here are lower than in the inner core; that is why this layer is a liquid

LAYERS OF THE EARTH: INNER CORE Ø Solid layer of nickel and iron Ø Highest temperature, pressure, and density

LAYERS OF THE EARTH: VIDEO Core of the Earth Video

LITHOSPHERE & ASTHENOSPHERE

Mantle Lithosphere Crust Inner Core Asthenosphere Outer Core

EARTH’S STRUCTURE