CLASSIFICATION OF ROCKS 8.E.2.2

Warm up  What does erosion do?  A. changes rock chemically  B. changes rock particles into different rock  C. it breaks rock down physically  D. it moves pieces of rock

Quiz ( Mechanical or Chemical)  1. Plants wedge their roots in to rocks and push it apart  2. Acid rainwater seeps into seeps into the ground and dissolves limestone rock  3. Rust occurring in rocks that contain iron  4. water freezing and expanding pushing the rock apart  5. Water causing rocks to rub against one another breaking it down

Classification of rocks  Rocks are always forming and changing  Scientists classify rocks based on the way they form  3 types of rock- sedimentary, igneous and metamorphic

Sedimentary rock  Formed from layers of sediment that was deposited at the bottom of rivers, lakes, and oceans  Weight of the layers compact and cement the sediment together to form sedimentary rock  Examples: sandstone, shale, limestone  Many have visible layers

Sedimentary rock

Igneous rock  Igneous rock forms when melted rock cools and hardens  Some forms from magma and other forms from lava  Magma- large, coarse grains  Lava- small, fine grains

Metamorphic rock  Metamorphic rock forms when existing rock is exposed to high heat, pressure or both  Happens deep inside earth Granite changed into Gneisis

Rock cycle  Rock cycle the continual change of rock from one kind to another  Any of the 3 major types can change into one of the other types.

Rock Cycle