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Slide 2 Weathering Slide 3 Weathering is the breaking down of rocks and other materials on the earths surface Slide 4 In other words, Weathering is when rocks are broken into soil, sand, and sediment (tiny pieces or particles). Slide 5 Weathering involves two processes that often work together to decompose or break down rocks. Slide 6 What are 2 Types of Weathering? Slide 7 Chemical & Mechanical Weathering Slide 8 Chemical weathering, or decomposition, takes place when some of the rocks minerals are changed into different substances. Slide 9 Chemical processes that cause weathering Dissolution- Soluble compounds such as limestone are dissolved. This often forms caves. Acid dissolves minerals in rocks (examples: carbonic acid, acid rain and plant acid) Acid rain can weaken rocks, corrode metal and even kill trees. Oxygen combines with iron minerals and sulfur minerals changing the composition of the rock and forming rust. This is called oxidation. Slide 10 Chemical processes that cause weathering Dissolution- Soluble compounds such as limestone are dissolved. This often forms caves. Acid dissolves minerals in rocks (examples: carbonic acid, acid rain and plant acid) Acid rain can weaken rocks, corrode metal and even kill trees. Oxygen combines with iron minerals and sulfur minerals changing the composition of the rock and forming rust. This is called oxidation. Slide 11 Plant acid? Slide 12 Lichens such as these growing on the rocks in the picture can produce weak acids that react with the rock. Slide 13 Chemical processes that cause weathering Dissolution- Soluble compounds such as limestone are dissolved. This often forms caves. Acid dissolves minerals in rocks (examples: carbonic acid, acid rain and plant acid) Acid rain can weaken rocks, corrode metal and even kill trees. Oxygen combines with iron minerals and sulfur minerals changing the composition of the rock and forming rust. This is called oxidation. Slide 14 Acid rainwhat is the cause? Slide 15 How acid rain forms Slide 16 Slide 17 What causes it? Slide 18 Slide 19 Slide 20 Slide 21 Slide 22 What are the effects? Slide 23 Slide 24 Slide 25 Slide 26 Acid Rain 1908 to 1969 Acid rain has eaten away this limestone statue. Slide 27 3000 year old Egyptian Obelisk 3000 year old Egyptian Obelisk after 100 years in NY Slide 28 Slide 29 Slide 30 http://www.epa.gov/acidrain/educati on/site_students/acid_anim.html http://www.epa.gov/acidrain/educati on/site_students/acid_anim.html Slide 31 Chemical processes that cause weathering Dissolution- Soluble compounds such as limestone are dissolved. This often forms caves. Acid dissolves minerals in rocks (examples: carbonic acid, acid rain and plant acid) Acid rain can weaken rocks, corrode metal and even kill trees. Oxygen combines with iron minerals and sulfur minerals changing the composition of the rock and forming rust. This is called oxidation. Slide 32 Oxidationwhat is it? Slide 33 Oxidation reactions involve a increase in oxidation state--in other words, the transfer of electrons from a compound that is oxidized to the compound that oxidizes it. Oxygen gas is a major component of Earth's atmosphere and is fairly reactive--so much so, in fact, that it's good at combining with metals and compounds in minerals, oxidizing or "rusting" them. Slide 34 Huh?? Slide 35 the interaction between oxygen molecules and all the different substances they may contact oxygen Slide 36 Oxidization Oxidation turned these rocks in Nevada's Valley of Fire red. Slide 37 Slide 38 Slide 39 Slide 40 Slide 41 Chemical processes that cause weathering Dissolution- Soluble compounds such as limestone are dissolved. This often forms caves. Acid dissolves minerals in rocks (examples: carbonic acid, acid rain and plant acid) Acid rain can weaken rocks, corrode metal and even kill trees. Oxygen combines with iron minerals and sulfur minerals changing the composition of the rock and forming rust. This is called oxidation. Slide 42 Dissolution-forming caves? Slide 43 Easy answerwhen rain water seeps into the ground and dissolves the limestone underneath. Slide 44 Slide 45 Slide 46 Slide 47 Linville Caverns, North Carolina