surface shaping activity of external forces

external forces

weather elements, water, living world

weather elements

rain, wind, humidity

water

rivers, glaciers, seawater

living world

animals, human activity

driving force of internal forces

internal heat

driving force of external forces

solar radiation

speed/rate of internal forces

fast

speed/rate of external forces

slow

outcome of internal forces

make surface “uneven” “up and down”

outcome of external forces

make surface “even”-weathering

types of weathering

physical and chemical weathering

physical weathering

only physical/mechanical changes occur—>NO CHEMICAL REACTION, only the particle size changes

example of physical weathering

cliff-rocks-stones-pebbles-sand

reasons for weathering

temperature fluctuation, freeze-thaw action(frost action) “biological weathering”

temperature fluctuation how

shrinks and expands unevenly-cracks-fall apart, in desertes(Daily), arctic areas(seasonally), high mountains(seasonally)

freeze-thaw action(frost action) how

rock with tiny cracks-water gets in cracks, freezes, ice +9% in volume-repeat-fall apart, in arctic areas, high mountains

biological weathering

plants roots grow-crack rocks-fall apart

chemical weathering

chemical raction/chemical changes occur

example of chemical weathering

karst formation, biological weathering

karst formation

limestone(CaCOˇ3)-dissolved by rain that is slightly acidic, it seeps into limestones and makes caves, sinkholes, dolinas

boilogical way of chemical weatehring

root acids, lichen acids- same thing but small scale

factors affecting the rate of weathering

type of rock, temperature, total annual precipitation

rate of weathering based on rock type

sedimentary rock faster than metamorphic rocks and igneous rocks

rate of weatehring based on temperature

high T faster than low T - mainly affects chemical weatehring bc molecules move faster in high T

rate of weatehring based on total annual precipitation

high faster than low

fastest rate of weathering where

in equatorial climate