Weathering and Erosion Project

By: Evan Donahoe


Weathering is when rocks over time wear off or break down. There are 3 different types of weathering. Physical, chemical, and biological. Physical weathering causes rocks to crumble. Water seeps into cracks and breaks down the rock. Physical weathering is caused by physical changes, such as when the temperature drops low enough, the water will freeze. When water freezes 32F or lower it expands outward. It slowly widens in between the cracks and splits the rock. When ice melts, water performs the act of erosion by carrying away the tiny rock sediments lost in the split.

physical weathering also occurs as the rock heats up and cools down. The changes in temperature causes the rock to expand or get compact. As this happens over and over again, the rock weakens, which then falls apart.

The continuous battering of rock surfaces with dust particles carried by the wind, river water carrying rocks and battering into other rocks, which is why down a river the rocks get to become smaller and rounder from sea wave crashing on the seashore and against cliffs etc. Layers of rocks graduallybreaking off.

Glaciers causes land mass to be seperated and changes the nature. That is why glaciers grind their way through creating lakes or valleys etc..

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Changing Earth: Weathering and Erosion

Chemical weathering

  1. Chemical weathering- chemical reactions break down the bonds holding the rocks together, but then causes the rocks attached to fall apart, by then forming smaller rocks of sediments.
  • Acid rain gradually break up rocks by chemical reactions. when fossil fuels are burned carbon dioxide and sulpher dioxide is escaped into the rain.
  • oxidation is Rusting. Sometimes a change in the color of a rock is an indication that oxidation has occurred. It is when over time oxidation puts the materiel into rust.

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biological weathering

It is the weakening of rock by plants, and animals.

Growing plant roots can cause expansion or pressure on rock. Although the process is physical, the pressure is exerted by a process growing roots. Biological processes can also produce chemical weathering, for example where plant root, breaks down rock minerals by making the rock’s chemical to weathering.

Also for plants they can grow in cracks, such as pavement or in wholes As they grow bigger, the roots push open the cracks and make them wider and deeper. Eventually pieces of rock may fall away. For animals such as rabbits can dig into a crack in a rock, making it bigger and widening the rock. Even people over time change the area. With people walking on landmarks and have material that can change the land.

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Erosion involves the movement of the weathered rock from one place to another. Such as a mud slide carrying a piece of land to a different place. In nature, large things are broken down into smaller things. Boulders become sand. Mountains are rained on and become hills. The pieces of the mountain become smaller pieces and go down the sides of hills. Weathering and erosion always happen in a downhill direction. Erosion is the break down of movement and weathering is the break down physically.

Erosion and Weathering for Kids -Causes and Differences
Weathering and Erosion Song