Grade 7 Science

1. Melanie Giambattista Grade 7 Science Earth and Space Science: Earth’s Crust and resources (EC)

2. Lesson 4a

3. Table of Contents 4. Three Main Types of Rocks 5. Warm-up 6. Igneous Rock 7. Igneous Rock 8. Types of Igneous Rock

4. Three Main Types of Rocks • Sedimentary • Igneous • Metamorphic Table of Contents

5. Warm-up - Igneous • Comes from the Latin word, ignis, meaning “fire” • In your science journal, write what you think the word ignite means • Compare your definition with a classmate • Compare your definition with a dictionary definition Table of Contents

6. Igneous Rock • What does igneous mean? • Made from fire or heat • How do they form? • Igneous rock forms when molten lava (magma) cools and turns to solid rock. • Their formation depends on the minerals that are in the molten rock and how fast it cools • Magma is melted rock found below Earth’s crust, where temperatures and pressures are high. Any rock heated at great depths can melt into magma. • Lava – magma that breaks through Earth’s surface, in the form of avolcanic eruption. Table of Contents

7. Igneous Rock • How is igneous rock classified? • Igneous rock is classified based on whether it was formed above or below the Earth’s surface • Igneous rocks are formed when molten rock cools. There are five different types of igneous rocks: granite, diorite, gabbro, periodotite, and pegmatite. • Intrusive rock - when magma cools and hardens below the surface • Ex) Granite • Extrusive rock – rock that forms when lava cools on earth’s surface • Ex) Obsidian Table of Contents

8. Types of Igneous rock: • Obsidian: is glassy and smooth, it forms when lava cools quickly on the surface • Pumice: is full of air pockets that were trapped when the lava cooled, it is the only rock that floats • Granite: is generally light coloured, the slow cooling at depth in the Earth produces larger crystals (coarse grained) that can easily be seen • Can you identify what rock (picture) corresponds to each description? Table of Contents