Grade 8 Changing Earth's Surface PDF

Grade 8 Changing Earth's Surface Chapter 3 Section 2 Instructions - Copy the notes into your notebook. - Leave a line or two in between each entry in case you want to add something later. - Answer all review questions in your notebook, you may need to refer to your textbook for some questio...

Grade 8 Changing Earth's Surface Chapter 3 Section 2 Instructions - Copy the notes into your notebook. - Leave a line or two in between each entry in case you want to add something later. - Answer all review questions in your notebook, you may need to refer to your textbook for some questions. - Watch all videos, there is important information in each one. You do not need to take notes on them but feel free to write down of interesting info. (Hint: You may change the speed while viewing or watch more than once) Essential Questions What is the difference between physical and chemical weathering? How do water, ice, and wind change Earth's surface? Breaking Down Earth Materials Processes that wear away and break down mountains are often so slow that it is difficult to see changes in the mountains during a human’s lifetime. Breaking Down Earth Materials The mechanical and chemical processes that change Earth’s surface over time are referred to as weathering. Breaking Down Earth Materials The material formed from rocks broken down by weathering is sediment. Breaking Down Earth Materials Sediment produced by weathering can be rock fragments, sand, silt, or clay. Breaking Down Earth Materials The process of breaking down rock without changing the composition of the rock is called physical weathering. Breaking Down Earth Materials Rocks can break as a result of plate motion or when a boulder rolls off a cliff. Breaking Down Earth Materials Water seeping into cracks in rocks can freeze and shatter the rock. Breaking Down Earth Materials The force from plant roots growing in cracks in rocks can pry the rock open. Breaking Down Earth Materials The process that changes the composition of rocks is called chemical weathering. Breaking Down Earth Materials Some minerals, such as calcite, can dissolve in slightly acidic water, such as rainwater. Breaking Down Earth Materials Other minerals react with carbon dioxide or oxygen in the air to form new minerals. Breaking Down Earth Materials Abundant water and higher temperatures speed up chemical weathering. Moving Earth Materials The term erosion is used to describe the moving of weathered material, or sediment, from one location to another. Moving Earth Materials The laying down or settling of eroded material is deposition. Moving Earth Materials The downhill movement of a large mass of rocks or soil due to gravity is called mass wasting Moving Earth Materials On tall mountains or steep slopes, the force of gravity can create a type of mass wasting called a(n) landslide. Moving Earth Materials The energy needed to move rocks and soil can come from gravity, flowing water, wind, and moving ice. Moving Earth Materials Most erosion and transport of sediment is carried out by flowing water. Moving Earth Materials Faster water can carry larger pieces of sediment than slower water. Moving Earth Materials When water slows, the sediment in the water is deposited on the sides of the river. Moving Earth Materials When rivers enter oceans or lakes, sediment also is deposited, forming land features called deltas. Moving Earth Materials Erosion by wind can be the most important process that changes landforms in deserts. Moving Earth Materials Examples of landforms made by wind include sand dunes and ripples. Arches N.P. Ice In cold climates, such as high mountains or near the poles, large masses of ice, formed by snow accumulation on land, that move slowly across Earth’s surface are called glaciers. Ice The force of gravity causes glaciers to flow and slide downhill, weathering the rocks over which the ice moves. Ice Glaciers can pick up sediment and then deposit it when they melt. Glaciers and Cape Cod What about Yosemite? Plate tectonics explains many of Earth’s surface features and the processes that occur on it. Climate, or the average weather in a region over a long period of time, affects the processes that move Earth material. Review Questions 1. How is weathering related to sediment? 2. What processes can break rock into smaller pieces? 3. What is the difference between chemical and physical weathering? 4. What provides the forces that can cause rock to move down hill? 5. What causes most erosion on Earth? The End