This week we wrapped up Earthquakes.  We learned that seismic waves are broken into 3 types. The instrument that is used to record the ground movement during an earthquake is called a seismograph.  The first wave to arrive is called the P wave or primary wave.  It arrives first and moves like a slinky for it compresses solids and liquids in a back and forth motion.  The second wave to arrive to called the S wave or secondary wave and it goes through solids only by cutting through rock at right angles (side to side and up and down).  The last wave to arrive is called the surface wave.  It is the most destructive type of wave because it moves along the surface of the land.  With this knowledge, students made a seismogram by shaking their table to create seismic waves for a weak and strong earthquake.  Students observed the the STRONGER the earthquake the BIGGER the wave.

Using their knowledge of P and S waves, students realized that the longer the dead time is between the P and S wave arrival, then the farther the earthquake was from the epicenter (the directly on earth’s surface above the focus or the point underground where the earth originates.  The last part of the puzzle was for students to realize how scientist find the epicenter of an earthquake.  Students realized that using 3 seismographs students can find the epicenter by finding where all 3 seismographs intersect.  Students had a enjoyable time being seismologist on their Earthquake Webquest.

Lastly, we discussed how scientist predict and analyze earthquake strength and damage. The Mercalli Scale (which measures the dollar amount of damage), The Richter Scale which measures the size of the seismic waves), and the Moment Magnitude Scale (which measures the amount of energy an earthquake releases). Also new to students will be the instruments used to monitor faults. We will be discussing Creep Meters (which measure ground movements in opposite directions), Tiltmeters (which show how much the crust is tilting) and GPS satellites. Before our test on Friday, students checked their Volcano and Earthquake packet and  played a Partner Challenge Crossword Puzzle as we reviewed Volcanoes and Earthquakes

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