2 The Effects of Weathering Weathering is the process that breaks down rock and other substances on Earth's surface.What contributes to weathering?HeatColdWaterIce
3 The Effects of Weathering Forces of weathering break rock into smaller pieces.Erosion carries the pieces away.Erosion is the movement of rock particles by wind, water, ice, or gravityThere are two kinds of weathering:Mechanical weatheringChemical weathering
4 Mechanical Weathering Weathering where rock is physically broken into smaller pieces is called mechanical weathering.smaller pieces have the same composition as the original rockMechanical weathering breaks rock byFreezing and thawing (Ice wedging)PressureGrowth of plantsActions of animalsAbrasionAbrasion is the grinding away of rock, by rock particles carried by water, ice, wind, or gravity.
7 Chemical WeatheringChemical weathering is the process that breaks down rock through chemical changes.The agents of chemical weathering include:WaterOxygenCarbon dioxideLiving organismsAcid precipitation (acid rain)Chemical weathering produces rock particles that have a different mineral makeup from the rock they came from.
9 Chemical and Mechanical Weathering Chemical and mechanical weathering often work together.11. As mechanical weathering breaks rock into pieces, more surface area becomes exposed to chemical weathering.
10 Water and weathering How does water contribute to weathering? 12. Water is the most important agent of chemical weathering.Water weathers rock by dissolving it.Over time, many rocks will dissolve in water.
11 Water and weathering13. Water can also freeze, expand in rock and break it apart. (Ice wedging)
12 Oxygen How does oxygen contribute to weathering? The oxygen in the air is an important cause of chemical weathering.Think of a Bicycle or metal tool left outside in the rainIron combines with oxygen in the presence of water in a process called oxidation.The product of oxidation is rust.Rust makes rock and metal soft and crumbly
14 Living Organisms How do living organisms contribute to weathering? Weak acids around the roots slowly dissolve rock chemically.
15 Acid Rain How does acid rain contribute to weathering? Over the past 150 years, people have been burning large amounts of fossil fuels (coal, oil, and gas) for energy.Burning these fuels can pollute the air.These fuels react chemically with the water vapor in clouds, forming acids.These acids mix with raindrops and fall as acid rain.Acid rain causes very rapid chemical weathering like the picture seen before…..
17 Rate of WeatheringThe most important factors that determine the rate at which weathering occurs areType of rockSedimentary, Igneous, MetamorphicClimate
18 Permeable Rocks Some rock weathers easily because it is permeable. Permeable means that a material is full of tiny, connected air spaces that allow water to seep through it.Permeable rock weathers chemically at a fast rate
19 Climate How does climate contribute to weathering? Climate refers to the average weather conditions in an area.It’s not the same thing as weather.Both chemical and mechanical weathering occur faster in wet climates.Chemical reactions occur faster at higher temperatures.