Unit D Studay Guide



Study Guide for Unit D:  Plate Tectonics

 Activity 38: Beneath Earth’s Surface Key Points

1.        The earth is made up of several  layers. 

These layers are:

The crust (solid)

The mantle (top part is solid, bottom is liquid)

The outer core (liquid)

The inner core(solid)


2.       As you go down deeper into the earth, it gets hotter and there is more pressure.  The temperature at the inner core is over 6000 degrees Celsius!  (10,832 degree Farenheit!)

3.       The lithosphere is the solid part of the earth (the crust, and the upper part of the mantle)

4.       Magma is molten rock (rock that is so hot it has melted!) that is under the earth’s surface.

5.       Lava is what magma is called once it has erupted from a volcano and is on the surface of the earth.

6.       The force of a volcanic eruption is affected by the amount of gas in the lava.  The more gassy the lava is, the more powerful the eruption.


7.       There are three main types of volcanoes:

a.        Shield volcanoes (have less gassy lava and less explosive eruptions)

b.      Cinder cone volcanoes (are the smallest and most common)


c.       Composite volcanoes (have more gassy lava and are more explosive, like Mt. Saint Helens)

  Activity 37 Volcanic landforms

How were the eruptions of the less gassy and more gassy  volcanoes different?

          Activity 39-Earth Time 

Key ideas and terms

1.        Paleontologists  are scientists who use evidence from rocks and fossils to understand when events happened over the course of time.  (They are often associated with dinosaurs)

2.       They record time in periods of thousands, millions, and billions of years ago as geological time.  (Remember that geologists study they history of the earth.  Paleontologists study one specific part)