Types of rocks and how we use them Lessons 22-23

Learning Objectives (9Ec-d p ) Give examples of how the properties of rocks (sedimentary, metamorphic, igneous) inform our choices when building things. Describe the processes in the rock cycle which change the physical or chemical structure of rocks. heat and pressure, melting, cementing, chemical and physical weathering Erosion, deposition,

Igneous Rock formed from magma (underground) or lava (above ground)

Igneous Rock Granite- slow cooling pockets of magma (underground)- crystals and patterns are formed Obsidian is actually volcanic glass made by cooling quickly Pumice- full of holes and will float- comes from exploding lava

Properties that are useful Not porous Very hard Pleasing to the eye

Metamorphic Igneous and sedimentary rocks that have changed due to heat and pressure over millions of years shist and gneiss marble

Properties that are useful Not porous Slate roof Very hard Floor tiles

Sedimentary Made from particles of sand and rock deposited and then pressed together and cemented over time with heat and pressure

Common Sedimentary Rocks Limestone- used in cement Shale- formed from clay used to make bricks Gypsum- soft, used for plastering walls and decorations Sandstone- easy to shape, used for walls, buildings

Properties that are useful Porous let’s water through Soft Easy to cut

Which are the best for building Choice depends on what you want to use it for- sandstone is soft and easy to use but erodes faster than granite

Rock Cycle (page 20 in booklet, page 170 in text)

Chemical weathering Natural rain water is acidic (pH 5.6) reaction of acid rain on rocks with CaCO3 is the chemical reaction that forms CaSO4, CO2 and H2O

Physical weathering Rain, wind and ice

Erosion-water and wind

Deposition Heavy and small particles of mud and rock fall out of the river water at different places depending on the speed of the water

Assessment Tasks Booklet pages Pages 20-21: read and complete A3 mind-map or poster: (start this class and complete in next) Use page 22, your notes and textbook (page 170) to; Draw the rock cycle (10 marks) Gives examples of how the properties of rocks inform our choices when building things. (1 per type – 3 marks) Describes the processes in the rock cycle which change the physical or chemical structure of rocks. (7 marks- 1 per definition) heat and pressure, melting, cementing, chemical and physical weathering Erosion, deposition