Plant growth-‐ Plant growth is when a plant grows up into a rock and cracks it. The cause-‐ As the plant gets bigger so do its roots. The larger the roots grow, the more pressure it puts on the rock witch causes it to expand and eventually crack. Plant growth is physical weathering.

Mechanical Weathering through plant growth is the process in which plants break and crack rock exposing leaves and stems. You see this happening in sidewalks and large rock pieces.

There are two main types of weathering: physical and chemical. Physical, or mechanical, weathering happens when rock is broken through the force of another substance on the rock such as ice, running water, wind, rapid heating/cooling, or plant growth.

Plants and animals also cause chemical weathering. As plant roots take in nutrients, they remove elements from the minerals. This causes a chemical change in the rock.

Chemical weathering occurs when water dissolves minerals in a rock, producing new compounds. Hydrolysis occurs, for example, when water comes in contact with granite. Feldspar crystals inside the granite react chemically, forming clay minerals. The clay weakens the rock, making it more likely to break.

These examples illustrate physical weathering:

• Swiftly moving water. Rapidly moving water can lift, for short periods of time, rocks from the stream bottom.
• Ice wedging. Ice wedging causes many rocks to break.
• Plant roots. Plant roots can grow in cracks.

There are different types of chemical weathering processes, such as solution, hydration, hydrolysis, carbonation, oxidation, reduction, and chelation. Some of these reactions occur more easily when the water is slightly acidic.

With chemical weathering of rock, we see a chemical reaction happening between the minerals found in the rock and rainwater. The most common example of hydrolysis is feldspar, which can be found in granite changing to clay. When it rains, water seeps down into the ground and comes in contact with granite rocks.

However, chemical weathering involves a change in the chemical makeup of the rock. Examples of physical weathering include frost wedging, thermal expansion, and exfoliation. These examples of chemical weathering change the chemistry of the rock, or the minerals found in the rocks.

Oxidation is another kind of chemical weathering that occurs when oxygen combines with another substance and creates compounds called oxides. Rust, for example, is iron oxide.

In chemical weathering, the rock reacts with substances in the environment like oxygen, carbon dioxide, and water to produce new substances. For example, iron in rock can react with oxygen and water to form rust, making the rock reddish and crumbly. During mechanical weathering, no new substances are produced.

The primary agents in chemical weathering are water, oxygen, and acids.

Water is the most important agent of chemical weathering. Two other important agents of chemical weathering are carbon dioxide and oxygen.

Chemical weathering does not cause physical damage to rock but rather is a reaction between the chemical composition of the rock and outside chemicals. Chemical weathering can make a rock more vulnerable to physical weathering forces. Iron in rocks can react with oxygen to form iron oxide, or rust.

Types of Chemical Weathering

• Carbonation. When you think of carbonation, think carbon!
• Oxidation. Oxygen causes oxidation.
• Hydration. This isn’t the hydration used in your body, but it’s similar.
• Hydrolysis. Water can add to a material to make a new material, or it can dissolve a material to change it.
• Acidification.

Weathering is the wearing away of the surface of rock, soil, and minerals into smaller pieces. Example of weathering: Wind and water cause small pieces of rock to break off at the side of a mountain. Weathering can occur due to chemical and mechanical processes.

wedging

Water, ice, acids, salts, plants, animals, and changes in temperature are all agents of weathering. Once a rock has been broken down, a process called erosion transports the bits of rock and mineral away. No rock on Earth is hard enough to resist the forces of weathering and erosion.

Factors affecting weathering

• rock strength/hardness.
• mineral and chemical composition.
• colour.
• rock texture.
• rock structure.

Chemical weathering is caused by rain water reacting with the mineral grains in rocks to form new minerals (clays) and soluble salts. These reactions occur particularly when the water is slightly acidic.

Rainfall and temperature can affect the rate in which rocks weather. High temperatures and greater rainfall increase the rate of chemical weathering. 2. Rocks in tropical regions exposed to abundant rainfall and hot temperatures weather much faster than similar rocks residing in cold, dry regions.

Mechanical weathering breaks rocks into smaller pieces without changing their composition. Ice wedging and abrasion are two important processes of mechanical weathering. Chemical weathering breaks down rocks by forming new minerals that are stable at the Earth’s surface.

A physical property is a characteristic of a substance that can be observed or measured without changing the identity of the substance. Physical properties include color, density, hardness, and melting and boiling points. A chemical property describes the ability of a substance to undergo a specific chemical change.

The main difference between mechanical and chemical digestion is that the mechanical breakdown of large food particles into small food particles occur in the mechanical digestion whereas the chemical breakdown of compounds with a high molecular weight into compounds with a low molecular weight occurs in the chemical …

Chemical reactions break down the bonds holding the rocks together, causing them to fall apart into smaller and smaller pieces. Weathering causes erosion, the process of these rock particles being carried away and deposited in other level places.

Chemical weathering is the weakening and subsequent disintegration of rock by chemical reactions. These reactions include oxidation, hydrolysis, and carbonation. These processes either form or destroy minerals, thus altering the nature of the rock’s mineral composition.