Surface Events & Landforms. Mrs. Green

Transcription

1 Surface Events & Landforms Mrs. Green

2 Bell Work 1) Which event MOST likely causes the slowest change to the surface of Earth? a) Earthquake b) Landslide c) Volcano d) Wind 2) When cold weather freezes water in the cracks of rocks, which would MOST likely happen? a) The rocks would become rounded b) The rocks would be used for shelter c) The rocks would be moved by the wind d) The rocks would break into smaller pieces 3) Jagged mountains would MOST likely become rounded hills through which process? a) Erosion b) Deposition c) Volcanic activity d) Chemical change

3 Weathering Weathering = a process that breaks down rock and other substances of Earth s surface. Erosion = removal of rock particles by wind, ice, or gravity Together, weathering and erosion work continuously to wear down the material on Earth s surface. Weather acts slowly, but over time will break down the largest and hardest of rocks: there are two kinds of weather

4 Two types of weathering: 1) Mechanical Weathering: Rock is physically broken down into smaller pieces by processes such as: freezing and thawing, release of pressure, plant growth, actions of animals and abrasion. Or grinding away of rock by rock particles carried by water, ice, wind, or gravity. Water expands when it freezes and acts as a wedge, slowly expanding rocks until pieces break off (a process called Ice wedging).

5 Two types of Weathering: 2) Chemical Weathering: A process that breaks down rocks through chemical changes such as those that include water, oxygen, carbon dioxide, living organisms and acid rain. Water most important cause of chemical weathering, it dissolves rocks over time. Oxygen in the presence of water will combine with iron in a process called Oxidation which produces rust. Carbon Dioxide dissolves in rain water and forms carbonic acid which easily weathers rocks such as marble and limestone. Living Organisms plants have roots that naturally produce weak acids when the grow., slowly dissolving rock around roots Acid rain results of burning fossil fuels which react with water vapor in clouds, forming acid; this causes rapid chemical weathering.

6 Bell work 1) The students watch ocean waves crash on a beach. Which statement describes what will MOST likely happen because of the waves? A) Grass on the beach will grow longer B) Sand from the beach will wash away C) Salt from the ocean will be left on the beach D) Currents in the ocean will become stronger 2) What is happening when rocks are broken down by both physical and chemical changes? A) Weathering B) Deposition C) Condensation D) Decomposing

7 Important factors: These factors determine the rate at which weathering occur; the type of rock and the climate. Climate refers to the average weather conditions in an area; both types of weathering occur faster in wet climates. Type of rock some minerals dissolve faster than others.

8 Water Erosion and Deposition Moving water is a major agent of erosion, especially along streams, rivers, at beaches, and underground. Stream = and active water channel that erodes land and transports sediment River = these form on steep mountain slopes and as it flows forms a variety of features such as: Water falls- which occur where a river meets an area of rock that erodes slowly Flood plains flat, wide area of land along a river that is often covered when the river overflows during a flood.

9 Water Erosion & Deposition Cont. River: Meanders loop-like bend in the course of a river and becomes more curved over time Oxbow lakes meander that has been cut off from sediments being deposited and damming up the ends Delta sediment deposited where a river flows into an ocean or lake and builds up a landform

10 Activity! Mechanical & Chemical Weathering Students will understand that wreathing can occur either through a mechanical or chemical process. Students need to describe each type of weathering as well as find an illustration or picture to show an example of each. Directions: The following chart lists serval causes for chemical and mechanical weathering. Use your notes to describe each type, then cut out the pictures and glue them to the correct box on the chart Finally cut out the full chart and paste into your notebook

11 Bell work: 1) Why should farmers NOT plow a hill? A) Plants will grow too fast B) Wind speed will increase C) Topsoil will erode D) Rain will evaporate too quickly 2) Which statement BEST explains what happens to large rocks under trees over time? A) The tree broke apart the rock B) The rock helped the tree grow C) The rock formed around the tree D) The tree provided support for the rock

12 Water Erosion & Deposition Cont. Groundwater = underground water that can cause erosion through a process of chemical weathering forming caves. Two types of rock formation can be made from this: Stalactite formed from deposits in dripping groundwater that hang on the roof of a cave Stalagmite formed though deposits that build up a cone-shape on the cave floor

13 Water Erosion & Deposition Cont. Waves = these shape the coastline through erosion by breaking down rock and transporting sand and other sediment onto the beach. Beach an area of deposited sediment that was carried in by waves

14 Wind erosion & deposition Wind- causes erosion by deflation or the process by which wind removes surface materials and abrasion. Two common types of wind-blown deposits are dunes, piles of wind blown sand and loess, or a crumbly, wind blown deposit of silt and clay. Deposition = the laying down or settling of eroded material

15 Activity! Water Erosion Directions: Cut out the following land features created by water below. Fold each like a matchbook and the solid lines Write a description of each diagram on the inside of each matchbook Take each matchbook and glue into your notebook

16 Bell work 1) what MOST likely caused a sinkhole to form? a) Wind blew away the soil b) Animals dug into the soil c) Water eroded underground rock d) Heavy objects crushed the ground 2) A canyon was MOST likely created by which? a) A glacier moving through a valley b) An earthquake in a desert c) A volcanic eruption on an island d) A river cutting through rock

17 Mass movement & Glaciers Remember: weathering, erosion and deposition work in a continuous process that wears down and builds up earth s surface. Remember: forces that cause erosion include gravity, running water, glaciers, waves and wind. Mass wasting = downhill movement of a large mass of rocks or soil because of the pull of gravity. Example: landslides, mudslides, slump and creep.

18 Mass movement & Glaciers Glacier = large mass of ice that formed on land and moves slowly across Earth s surface; they form in areas where the amount of snowfall is greater than the amount of snowmelt. Two types of glacier: Continental glacier (or ice sheets) covers large areas of land and move outward from central location; these exist today on Antarctica and Greenland. Valley glacier (alpine) long narrow glacier that forms when snow and ice build up high in a mountain valley

19 Activity! Glaciers Student will identity land and water features created by erosion and deposition by a glacier. Directions: Write the letter of each glacial landform that matches with its description below. Color the letter of each landform made by erosion YELLOW Color the letter of each landform created by deposition BLUE Finally cut out the completed diagram and descriptions below and paste into your Science notebook Mrs. Green will come around and check everyone s work and check for the correct answers

20 Bell work 1) Which of these is MOST likely caused by the action of water, wind and animals? a) Mountains b) Erosion c) Earthquake d) Volcanic eruptions 2) Deposition of sediment during floods makes the land neat some rivers? a) Acidic b) Fertile c) Hilly d) unstable

21 Two process by which glaciers erode the land: Plucking as a glacier flows over the land, it picks up rocks and large boulders dragging them across the land. Abrasions this is caused by plucking or gouges and scratches in the bedrock

22 Two process by which glaciers erode the land: When a glacier melts, it deposits the eroded sediment creating various landforms which include: Till a mixture of sediment that is deposited directly on the surface Moraine a ridge formed from till deposited at the edge of glaciers Kettle a small depression that forms when a chunk of ice is left in till then eventually melts

23 Bell work 1) Flooding rivers can help or harm the environment. Which of these would be a helpful effect from a flood? a) Eroded riverbanks b) More fertile soils c) Fewer trees near rivers d) Less habitat for aquatic animals 2) Which land feature is MOST likely the result of a glacier? a) Large, arid desert b) Deep, bowl-shaped lake c) Long crack in the ground d) Volcanic mountain range

24 Bell work Find your assigned seat please Get your notebook out and a pen or pencil Today we are completing the study gudie for the test!

25 Test Day! I will be handing out the post-test My expectations are: Once the test is handed out every one is absolutely quite and respect other students who are still taking the test. No writing on my class set of the test! The purpose of a pre-test is to see what information you know and don t know about this unit. Once you have completely the test raise your hand and I will come get the test. Please sit quietly while you wait! You may color or read a book if you have one. Once everyone has finished we will start are new lesson