Science and Technology I Mid-Year Exam 2012 A Whole Lotta Shakin’ Going On Review

The Earth has three main layers: –Crust (outer layer) –Mantle (middle layer) –Core (inner layer) Inner core Outer core EARTH’S STRUCTURE

The lithosphere is made up of the crust and upper mantle. The lithosphere is broken into pieces called tectonic plates. TECTONIC PLATES

The tectonic plates are constantly moving because the mantle flows since it is partially melted. This moves the continents. Alfred Wegener developed the theory after making two observations: 1. The continents looked like they fit together 2. Fossils of land animals found on both sides of the ocean on different continents. CONTINENTAL DRIFT

The tectonic plates move in different directions: moving together moving apart sliding past each other MOVEMENTS

Orogenesis means mountain formation Mountains occur at convergence zones, when the tectonic plates have about the same weight. Erosion changes the mountain over time. OROGENESIS

Usually occur at transform boundaries. As the plates try to push past each other, they get stuck. When they finally manage to break free, a lot of energy is released and the ground shakes. That is an earthquake. The location where the earthquake began is called the epicenter. EARTHQUAKES

Seismologists (people who study earthquakes) use a machine called a seismograph to detect and record earthquakes. Earthquakes are measured on the Richter scale, which ranges from 0-10 (10 is the worst possible earthquake). EARTHQUAKES

Volcanoes usually occur at convergent or divergent boundaries. At a convergent boundary, one tectonic plate is heavier than another, and so it slips underneath, melts, and the pressure inside the earth forces the magma to come out. When the melted mantle is inside the Earth, it is called magma. When it is outside, it is called lava. VOLCANOES

The Ring of Fire is an area in the Pacific Ocean where the majority of volcanoes occur. VOLCANOES

The word tsunami means giant wave. Tsunamis are caused by an underwater earthquake or volcano, which makes waves. As the waves approach land, the become bigger and more powerful. TSUNAMIS

A tsunami measures the intensity and duration of an earthquake. The ones we made in class looked like this: SEISMOGRAPHS

To make our seismographs, we used: –A cereal box –A cup –String –Sand –Paper –Pen SEISMOGRAPHS

When we simulated an earthquake, the box shook, but the sand kept the cup and the pen steady. We pulled the paper through the slit in the box and saw how the pen made earthquake lines. SEISMOGRAPHS

A teacher could use this type of seismograph in class to demonstrate how a real seismograph works. SEISMOGRAPHS