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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 1 - Now. Igneous Rocks. How do igneous rocks form? What are the common types of igneous rocks?.
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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 1 - Now
Igneous Rocks • How do igneous rocks form? • What are the common types of igneous rocks? Lesson 2 Reading Guide - KC
Igneous Rocks • extrusive rock • volcanic glass • intrusive rock Lesson 2 Reading Guide - Vocab
Igneous Rock Formation • When volcanic material erupts and cools and crystallizes on Earth’s surface, it forms a type of igneous rock called extrusive rock. • Volcanic glass is rock that forms when lava cools too quickly to form crystals. • Among the most noticeable features of some extrusive igneous rocks are holes that are left after gas escapes. Lesson 2-1
Igneous Rock Formation(cont.) Igneous rocks that form as magma cools underground are called intrusive rocks. intrusive from Latin intrudere, means “to push in” Lesson 2-1
Intrusive and Extrusive Rocks Lesson 2-1
Igneous Rock Formation(cont.) How do igneous rocks form? Lesson 2-2
Geologists determine whether an igneous rock is extrusive or intrusive by studying the rock’s texture. Lesson 2-2
Igneous Rock Identification • 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. Lesson 2-2
Igneous Rock Identification(cont.) • 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. Lesson 2-2
Igneous Rock Identification(cont.) How are extrusive and intrusive rocks different? Lesson 2-2
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 - VS
What erupts onto Earth’s surface during a volcanic eruption? A. sediment B. volcanic glass C. pumice D. magma Lesson 2 – LR1
Which of these forms when lava cools too quickly to form crystals? A. extrusive rock B. intrusive rock C. volcanic glass D. magma Lesson 2 – LR2
What kind of rock forms when magma cools underground? A. intrusive B. extrusive C. crystallized D. mineral Lesson 2 – LR3
Do you agree or disagree? 3. Large crystals form when lava cools quickly on Earth’s surface. 4. Igneous rocks form when cooling magma crystallizes. Lesson 2 - Now