Weathering Notes

Weathering 1

Weathering is when rocks break down into the environment near earth surface. When looking at a mountain you will see piles of loose rocks from landslides weathering that has loosened them from the solid rock of the mountain. When you dig in the farm the soil you dig is the natural product of slow gradual weathering of rocks. There are two classes of weathering. Mechanical weathering: this method tear apart rocks by breaking them down. Physical fracture or pull rocks a part. Chemical weathering: this breaks down rocks atom by atom through chemical reaction. When you hit a rock into pieces by smashing it is mechanical weathering. This tear rocks apart by cracking them and they make them even smaller. Water expands when it freezes. When the temperature drops below freezing the upper surface freezes because of the air. Each freezing may wedge open just a tiny amount. Exfoliation is a term that describes peeling of layers like your skin. But for weathering it will peel of sheet of rocks. Crystals are rocks also expand and contract as they hear a cool. It does not expand that far.Rocks are poor conductors of heat. If the rock cannot take the heat it tends to break. Salt crystals grow in rock fracture or in small pores between sedimentary grains can cause rocks to lessen up and break. This happens when salty water gets into the rock of the water produces. Weathering for crystal growth is fairly restrictive there must be ready source of salt water. Ant other wedging is caused by tree roots. They are tiny and penetrate easily into fine fractures of rocks. The roots will grow anywhere. Abrasion is the mechanism of rocks breaking. The rocks will fall off the cliffs and will be left under the ground. Nearly all types of sediments. This could be in cold and wet environments. It need to be in a high elevation. 

Weathering 2

Rock will always wear away. When that happens it is called weathering. There are actually 3 different types of weathering physical, chemical and biological.

Physical Weathering

This weathering is caused by physical changes. So are when changes in temperature, freezing and thawing and the effects of wind and rain. When the rock gets hot it will expand a little when the rock gets cold it will contracts a little. Wind and rain can cause weathering.  The water expands slightly when it freezes into ice.

Biological Weathering

Animals and plants can wear away rocks. When this happens it is called biological weathering. When an animal digs into the ground also known as burrowing it will leave a crack in the rock making it split. When you see weeds grow in a crack of the rock that is because of plant roots. Plant roots can grow in side cracks. They will keep growing and the crack will keep getting bigger and bigger.

Chemical Weathering

The rocks weathered by chemicals is called chemical weathering.  Rainwater is naturally slightly acidic because of carbon dioxide. Minerals may react to rain water and cause the rock to be weathered.