Rabu, 21 November 2012

contoh teks explanation

he Process of Rain

Water in the earth is kept in many places like the ocean, the ocean, the river and the lake. But don't be wrong, the plants leaves and the land also kept water.

Each day, this water will evaporate with help of the sun. The process where water evaporates from plants is called transpiration. Afterwards the vapour will experience the process of condensation where the vapour will condense and turn into a cloud. The form of the cloud always changes according to weather conditions.

The clouds will move to different locations with the help of wind that bellows vertically or horizontally. The movement of the vertical wind results in the cloud forming big 'lumps'. After that, the wind increases the size of the cloud and each cloud will overlap. Finally the cloud will reach the atmosphere that has a lower temperature. Here the particles of water and ice is formed.

Eventually, the wind can not support the weight of the cloud and so the cloud that is full with water will experience a process called precipitation or the process where rain or hail falls to earth. 

How a Spider’s Web Forms

A Spider web looks delicate but it is very strong. It can hold 4000 times a spider’s weight. But how does it form.

First the spider spins a thread of silk. The thread gets blown over to a branch by teh wind. Then she makes another two threads and makes a Y shape. Next she makes more threads and they look like spokes off a wheel. Then the spider goes in a spiral, out and back in, sits in the middle and waits for food. 

This is how a web is formed.

 

Venus Flytrap

The Venus Flytrap is an extraordinary plant. It is a carnivorous (flesh eating) plant which can digest flies and other insects.

When the ‘trap’ is open, it looks like a large seashell with sharp, spiky ‘teeth’. It has bright colours and a beautiful scent.

Insects are attracted to the plant because of its vibrant colours and its sweet-scented nectar. The insects land on small ‘trigger’ hairs of the trap and this pressure causes the trap to close. If the insect is too small, the chamber will not close, because there is not enough pressure. Once the trap has swallowed an insect it takes ten days to diggest it.

The Venus Flytrap prefers tropical weather and so it is found in places like South America. It is often used by people to catch the annoying insects that fly around their houses. In my opinion it’s very useful plant!

Early Dams

Dams have been built on rivers and streams all over the world for thousands of years. In the Egyptian desert cast of the Nile River are the remains of a masonry dam that probably dates back to 2500 BC. Other ancient darns have been found in present day Iraq, Syria, and Arabia. Most of these dams were used for collecting and storing water for irrigating the fields in the dry desert regions.

Early dams were built with rocks, earth, and wood. These dams worked fairly well unless the pressure of the water became too great, or they were overtopped by high flows of water; Then the dam would be washed away. Gradually men learned how to design dams that could withstand great pressure. New materials were added ’to strengthen the darns.

 

 

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