**Get out your earbuds or ask the substitute to borrow headphones.  Watch the following VIDEOS that are related to the topics covered in this section.

Normally, water changes into the gaseous state at 212 degrees fahrenheit.   In the case of a geyser, the water is able to become superheated (300 degrees fahrenheit under the ground, but remains liquid).  The reason for this superheated temperature is because the water is under extreme pressure and as a result, the water DOES NOT undergo a phase change.  

Similarly, the layer of the Earth known as the Asthenosphere remains in the solid rock state even though the temperature is approximately 4000 degrees fahrenheit (well above the melting point of the rock).  It remains in this solid state (resisting a phase change) because it is under extreme pressure from the weight of the Lithosphere above it.  

What would happen to the Asthenosphere material if some of the overlying pressure of the Lithosphere is removed???  By watching the geyser videos, you should be able to come up with an answer to that question.

In the remaining time in the class (if there is any), you can review over the notes that you have downloaded into GoodNotes or review the Quizlet flashcards below.