1. BELL RINGER 5-3-10 1. What is it called when waves bend as they go from one type of medium to the other?  What is it called when waves bend around a corner or through an opening?  What is it called when waves bounce back from a surface because they are unable to travel through it?  Write an example of reflection.  Write an example of refraction.

2. Chapter 15 Section 4 Seismic Waves

3. Seismic Waves  These waves travel through rock, and provide an effective way to "see" events and structures deep in the Earth.  The word seismic comes from the Greek word “seismos” which means earthquake.  Seismic Wave = Earthquake Wave

4. Three basic types: 1. P-waves 2. S-waves 3. Surface waves

5. 1. P waves  P-waves, or Primary waves, travel the fastest and are longitudinal waves. They are made up of compressions and rarefactions.  They can move through both liquids and solids.

6. 2. S waves  S-waves or secondary waves, are transverse waves that travel slower than P-waves.  They can travel through solids but not liquids.

7. 3. Surface waves  Surface waves travel along the outer surface of the earth at slower speeds than P and S waves.  Particles move in rocks like waves would move in water, in a circular motion.  They cause most of the destruction during an earthquake. These waves consist of longitudinal and transverse waves (side-to-side and up- and-down motions).

8.  The 3 types of seismic waves The 3 types of seismic waves The 3 types of seismic waves

9.  A seismograph is an instrument scientists use to detect earthquakes.  A seismograph records the ground movements caused by seismic waves as they move through Earth.

10.  A tsunami is an underwater earthquake.

11. Current News  Video - Breaking News Videos from CNN.com (Oil Spill) Video - Breaking News Videos from CNN.com Video - Breaking News Videos from CNN.com  Flooding leaves at least 15 dead in Southeast - CNN.com Flooding leaves at least 15 dead in Southeast - CNN.com Flooding leaves at least 15 dead in Southeast - CNN.com

12. Earthquakes and Tornadoes HowStuffWorks Videos "Hurricanes and Tornadoes: Air Pressure“ HowStuffWorks Videos "Hurricanes and Tornadoes: Air Pressure“ HowStuffWorks Videos "What Are the Odds? Earthquake" HowStuffWorks Videos "What Are the Odds? Earthquake"

13. Tsunamis HowStuffWorks Videos "How Tsunamis Work“ HowStuffWorks Videos "How Tsunamis Work“ HowStuffWorks Videos "Tsunami" HowStuffWorks Videos "Tsunami"