Presentation on theme: "Lesson 1 - Now 1.Once a rock forms as part of a mountain, it does not change. 2.Some rocks, when exposed on Earth’s surface, undergo weathering and erosion."— Presentation transcript:
Lesson 1 - Now 1.Once a rock forms as part of a mountain, it does not change. 2.Some rocks, when exposed on Earth’s surface, undergo weathering and erosion. Do you agree or disagree?
Lesson 2 Reading Guide - KC How do igneous rocks form? What are the common types of igneous rocks? Igneous Rocks
Lesson 2 Reading Guide - Vocab extrusive rock volcanic glass intrusive rock Igneous Rocks
Lesson 2-1 When volcanic material erupts and cools and crystallizes on Earth’s surface, it forms a type of igneous rock called extrusive rock. extrusive rock Volcanic glass is rock that forms when lava cools too quickly to form crystals.Volcanic glass Among the most noticeable features of some extrusive igneous rocks are holes that are left after gas escapes. Igneous Rock Formation
Lesson 2-1 Igneous Rock Formation (cont.) intrusive from Latin intrudere, means “to push in” Igneous rocks that form as magma cools underground are called intrusive rocks.intrusive rocks
Lesson 2-2 How do igneous rocks form? Igneous Rock Formation (cont.)
Lesson 2-2 Geologists determine whether an igneous rock is extrusive or intrusive by studying the rock’s texture.
Lesson 2-2 If the crystals are small, the rock is extrusive. If all the crystals are large enough to see and have an interlocking texture, the rock is intrusive. Igneous Rock Identification
Lesson 2-2 Igneous rocks are also classified, in part, by magma composition, such as silica content. Magma composition, the location where the lava or magma cools and crystallizes, and the cooling rate determine the type of igneous rock that forms. Igneous Rock Identification (cont.)
Lesson 2-2 Igneous Rock Identification (cont.) How are extrusive and intrusive rocks different?
Lesson 2 - VS An extrusive igneous rock cools and crystallizes from volcanic material erupted on Earth’s surface. When lava cools fast, volcanic glass forms. An intrusive igneous rock forms as magma cools and crystallizes deep inside Earth.
Lesson 2 – LR1 A.sediment B.volcanic glass C.pumice D.magma What erupts onto Earth’s surface during a volcanic eruption?
Lesson 2 – LR2 A.extrusive rock B.intrusive rock C.volcanic glass D.magma Which of these forms when lava cools too quickly to form crystals?
Lesson 2 – LR3 A.intrusive B.extrusive C.crystallized D.mineral What kind of rock forms when magma cools underground?
Lesson 2 - Now 3.Large crystals form when lava cools quickly on Earth’s surface. 4.Igneous rocks form when cooling magma crystallizes. Do you agree or disagree?