Kamis, 15 September 2011

Contoh Teks Explanation

The Process of Rain

How a Spider’s Web Forms
This is how a web is formed.
Venus Flytrap
The Picher of Death
How It Works
Frogs are delightful creatures. Our country is home to more than 220 named species and they can be found in almost any Australian landscape. Most frogs lay eggs on land or in the water. Then, after the eggs hatch,
Tadpoles enter the water for two weeks to six months, depending on the temperature, before emerging as froglet (baby frog). Not all frogs do this. The hip~ pocket frog is a very interesting example of parental care. After the female hip-pocket frog has spawned, the male will lie on her eggs and about eight tadpoles wriggle up into each pocket where they grow into baby frogs. Australia’s two species of gastric brooding frogs are even more amazing. They swallow their fertilised eggs and hatch the tadpoles in their stomachs. Six weeks later the _froglets emerge from their mother’s mouth.
Petroleum products, such as gasoline, kerosene, home heating oil, residual fuel oil and lubricating oils, come from one source - crude oil found below the earth’s surface, as well as under large bodies of water, from a few hundred feet below the surface to as deep as 25,000 feet into the earth’s interior. Sometimes crude oil is secured by drilling a hole through the earth, but more dry holes are drilled than those producing oil. Pressure at the source or pumping forces crude oil to the surface.
Crude oil welts flow at varying rates, from ten to thousands of barrels per hour. Petroleum products vary greatly in physical appearance: thin, thick, transparent, or opaque. Their chemical composition is made up of only two elements: carbon and hydrogen, which form compounds called hydrocarbons. Other chemical elements found in union with the hydrocarbons are few and are classified as impurities. Trace elements are also found, but these are of such minute quantities that they are disregarded. The combination of carbon and hydrogen forms many thousands of compounds, which are possible because of the various positions, and varied joining of these two atoms in the hydrocarbon molecule.
The various petroleum products are refined from the crude oil by heating and condensing the vapours. These products are the so-chatted tight oils, such as gasoline, kerosene and distillate oil. The residue remaining after the tight oils are distilled is known as heavy or residual fuel oil and is used mostly for burning under boilers. Additional complicated refining processes rearrange the chemical structure of the hydrocarbons to produce other products, some of which are used to upgrade and increase the octane rating of various types of gasoline.
Early Dams

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