1. Chapter 2 Earth Layers and Seismic Waves 8-3.1 Summarize the three layers of Earth – crust, mantle, and core – on the basis of relative position, density, and composition. 8-3.2 Explain how scientists use seismic waves – primary, secondary, and surface waves – and Earth’s magnetic fields to determine the internal structure of Earth.

2. Earth Layers Today, You Will…. 1.Create a foldable of Earth and its layers. Glue into your ISN. 2.Copy notes located at your table inside your ISN. 3.Receive a chart of relative position, density and composition of Earth’s Layers to glue inside your ISN.

3. Seismic Waves Today, You Will… 1.Receive a chart of relative position, density and composition of Earth’s Layers to glue inside your ISN. 2.Copy notes into your ISN on Seismic Waves 3.Receive your Study Guide for your Test on February 2 nd.

4. Recall that…. 1. Waves transmit energy but not matter. 2.Mechanical waves require the particles of the medium to vibrate in order for energy to be transferred. Electromagnetic waves are waves that can travel through matter or empty space where matter is not present. 3.Basic properties of waves are influenced by several factors including frequency, amplitude, wavelength and speed.

5. Seismic Waves Earthquakes produce three types of waves with different behaviors as they travel through materials. 1.Primary Waves (P Waves) 2.Secondary Waves (S Waves) 3.Surface Waves (L Waves)

6. Seismic Waves: Primary (P) waves Move out from the earthquake focus, the point where the energy is released. Travel the fastest of the three waves. Move through solid and liquid layers of Earth. Push and pull rock creating a back-and-forth motion in the direction the wave is moving (longitudinal wave).

7. Seismic Waves: Secondary (S) waves Move out from the earthquake focus. Move slower than primary waves. Can only move through solid rock. Move at right angles to primary waves causing rocks to move up and down and side to side (transverse wave).

8. Seismic Waves: Surface (L) waves Form when P and S waves reach the surface. Can cause the ground to shake making rock sway from side to side and roll like an ocean wave.

9. Seismic Waves Scientists use the principle that the speed and direction of a seismic wave depends on the material it travels through. 1. Because of the behavior of these different waves, scientists have indirect evidence for the solid inner core and liquid outer core of Earth; 2. Because earthquake waves travel faster through the mantle than through the crust, scientists know that the mantle is denser than the crust.

10. Magnetic Field 1.The movement of materials in the outer core of Earth is inferred to be the cause of Earth’s magnetic field. 2.A compass needle will align with the lines of force of Earth’s magnetic field. 3.Iron and nickel are metals that easily magnetize, and are inferred to be the metals in Earth’s core.

11. View Website: https://www.khanacademy.org/science/cosmolog y-and-astronomy/earth-history-topic/seismic- waves-tutorial/v/seismic-waves