Transcript Weathering
Weathering Bell ringer 10/27/14 Title the next page in your science notebook: “Weathering notes” & Copy the following questions into your science notebook: • What is the difference between weathering and erosion? • What is the difference between mechanical and chemical weathering? • How do water, air, and organisms cause chemical weathering? • How do mechanical and chemical weathering work together to speed up the weathering process? Bell ringer: Wed. 10/28/14 • Open book to page 30, and use that chapter to write out 3 examples of chemical weathering, and • We will be exploring several different resources, including videos, reading, games and labs to answer the questions you copied into your science notebook for today’s bell ringer. MECHANICAL & PHYSICAL WEATHERING are the same thing Video: “A Look at Sinkholes: Florida's Most Common Natural Disaster” 1. In groups: Name 2 examples of physical weathering and one example of chemical weathering? 2. Whole class; Are there substances that are not chemicals? If so, what are some examples? After the video, you will answer the above questions in a group, then share your answers in class. Title: “Florida sinkhole video” 1. During the video, write down one example of a mechanical weathering. & 1 ex of chemical weathering SIGNS OF CHEMICAL: Bell ringer: copy these questions Compare & contrast the causes of cave formation and sinkhole formation. WRITE: “Earth’s cellar” 1. How are caves & sinkholes similar? 2. How are they different? 3. Which processes are physical ones and which are chemical? Read, “Earth’s cellar” Compare & contrast the causes of cave formation and sinkhole formation. 1. How are they similar? -both made from limestone & from water dissolving, both form via a chemical process 2. How are they different? Sink holes form when earth’s surface collapses; caves are often larger; caves usually have a ceiling, the inside of a cave is made of rock, while a sink hole is usually soil 3. Which processes are physical ones and which are chemical? Acidic water dissolving is a chemical process; when dirt and rock collapses in and slams into other rocks, soil, etc, that is physical weathering DEFINITIONS WEATHERING Brainstorm: 1) What is it? 2) What can cause it? 3) How does weathering change the surface of the Earth? Possible Causes: Chemical Weathering Examples 1. oxidation- when iron or other metal deposits in rocks rust, they change color 1. Water and oxygen WEATHERING • Weathering= the breaking down of rock into smaller and smaller pieces. Is weathering constructive, destructive, or both? Why? -Weathering is destructive- it “tears down” rocks and landforms. 2 Types of Weathering Brainstorm 1) What can cause each type of weatheri ng? WEATHERING 1) Mechanical 2) Chemical Breaking down rocks by physical means Chemical breakdown of rock and minerals into new substances Possible causes: Possible causes: MECHANICAL WEATHERING 1. ANIMALS Little animals also help weathering by burrowing and digging through the ground. MECHANICAL WEATHERING 2. Ice Wedging – when water gets into cracks of a rock, freezes & thaws over & over again & splits the rock MECHANICAL WEATHERING Ice MECHANICAL WEATHERING 3. PLANT GROWTH • Roots of plants also push into the rocks and break them apart. They act like wedges and push the rocks apart. 4. Abrasion by Water WATER - rubs fragments against each other and wears away the surface of the rock by abrasion. – The faster the water, the greater the erosion MECHANICAL WEATHERING NONLIVING CAUSES . Abrasion- sediments carried by wind, water, or ice wear away rock by hitting & scraping against other rock Abrasion Wind • sandstone shapes eroded by coastal winds Sandblasting Abrasion WATER - rubs fragments against each other and wears away the surface of the rock by abrasion. – The faster the water, the greater the erosion Abrasion • Ice- Glaciers –The glacier gouges out chunks of rock and leaves scratches on the rock called striations CHEMICAL WEATHERING • CHEMICAL WEATHERING the chemical breakdown of rock and minerals into new substances CHEMICAL WEATHERING Water is considered to be the universal solvent. It dissolves many things – including rock • Over time, water can break down even hard rock like granite CHEMICAL WEATHERING 2) Oxygen Oxidation (rust) is a chemical reaction in which an iron combines with oxygen. CHEMICAL WEATHERING 3) Carbon Dioxide (CO2) -CO2 mixing with water creates Carbonic Acid that slowly dissolves limestone. (Acid in groundwater) -Caves CHEMICAL WEATHERING 4) Living Organisms Acids from decaying plants or fungi such as lichens breaks down rocks CHEMICAL WEATHERING 5. ACID PRECIPITATION is rain or snow that contains more acids than normal due to air pollution. The acid “dissolves” and “eats away” the rock WEATHERING How does weathering change the surface of the Earth? Mechanical Weathering Living Plant Animal Nonliving Roots of plants also push into the rocks and break them apart burrowing and digging through the ground -water gets into cracks of a rock, freezes Ice (glacie & thaws over & over again & splits the rock rs) -scratches on the rock called striations Wind wears away the surface of the rock by abrasion Water rubs fragments against each other and wears away the surface of the rock by abrasion. Chemical Weathering Living Plants Acids from decaying plants or fungi such as lichens breaks down rocks Nonliving Water universal solvent. It dissolves many things – including rock Acid rain rain or snow that contains more acids than normal due to air pollution. -acid “dissolves” or “eats away” the rock CO2 mixing with water creates Carbonic acid that slowly dissolves limestone Groundwater Oxidation chemical reaction in which an element combines with oxygen to form an oxide FORCES THAT CAUSE Weathering 1) Mechanical Living Plants Nonliving Ice - (Glaciers) 2) Chemical Living Plants Nonliving Water Wind Acid rain Groundwater Water Oxidation Animals Interactive Weathering • How are materials from the earth broken down?