Minggu, 29 Januari 2012

what is the explanation text????

An explanation is a set of statements constructed to describe a set of facts which clarifies the causes, context, and consequences of those facts.This description may establish rules or laws, and may clarify the existing ones in relation to any objects, or phenomena examined. The components of an explanation can be implicit, and be interwoven with one another.
An explanation is often underpinned by an understanding that is represented by different media such as music, text, and graphics. Thus, an explanation is subjected to interpretation, and discussion.In scientific research, explanation is one of the purposes of research, e.g., exploration and description. Explanation is a way to uncover new knowledge, and to report relationships among different aspects of studied phenomena.
Explanation
Explanation texts explain how or why things happen eg how acid soil affects farm productivity. Explanation begins by identifying the phenomenon (thing) that will be explained. (Phenomenon identification.) Then there is an explanation sequence which explains how things work. Example of an explanation: shows the structure and language features.
Writing explanations When writing explanations use:
• general nouns eg nutrients. • technical terms (often used) eg pH, acid
• present tense eg provide
• words that show cause and effect eg if.

Use the sample explanation text to answer these questions.
1 List some general nouns that are used in the text.
2 There are other technical terms used in the text. List some of these.
3 List some of the words (or phrases) that have been used to show cause and effect.

Explanation: example This sample explanation is labelled to show you the structure and language features of an explanation text.

title:The effects of acid soil

phenomenon identification : Soils with a pH of less than 7.0 are acid. The lower the pH, the more acid the soil. When soil pH falls below 5.5, plant growth is affected. Crop yields decrease, reducing productivity.

explanation sequence : Soils provide water and nutrients for plant growth and development. Essential plant nutrients include phosphorus, nitrogen, potassium and sulfur. Plants require other elements such as molybdenum, in smaller quantities. Some elements eg aluminium and manganese, are toxic to plants.
Nutrients become available to plants when they are dissolved in water. Plants are able to take up phosphate, nitrate, potassium and sulfate ions in solution.
The solubility of nitients changes with pH. In acid soils (low pH), molybdenum becomes less soluble and aluminium becomes more soluble. Therefore, plant growth may be affected by either a deficiency of molybdenum or too much aluminium.
Both crop and pasture plants are affected by acid soils. there may be a range of symptoms. Crops and pastures may be poorly established resulting in patchy and uneven growth. Plant leaves may go yellow and die at the tips. The root system of the plant may be stunted. Crops may yield less.Plants vary in their sensitivity to low pH. Canola and lucerne are very sensitive to acid soils so do not grow well. Lupins and triticale are tolerant to soils of low pH so they still perform well.Land can become unproductive if acid soil is left untreated. Incorporating lime into the soil raises the pH. Therefore, liming soil can reverse the effects of acid soil on plants and return a paddock to productivity.

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