Minggu, 14 Oktober 2012

Why is snow the color white?


Water in the pure form is colorless. If there are any impurities present, the color of the water changes. Snow also can take the color of other objects. For example, in the case of glaciers deep inside the ice block it appears blue in color. But, snow is slightly different from the ice. Snow is the collection of ice crystals that are tiny and attached to one another. The ice crystal is also clear and colorless while the accumulated crystals combine to form snowflakes.

The snow is visible to us due to the presence of light. Snow falls from the above in the atmosphere and reaches the ground. The ice crystals will enable the light falling on them to get reflected on their surface. There are multiple faces for the crystals and hence the light also gets scattered. Visible light has various wavelengths of light that are visualized by us. When light falls on any object some part of the light will be absorbed and the other part will get reflected. The reflected part of light reaches our eyes and makes us to recognize the colors.

The light fallen on the ice crystals also do not pass through the crystals for long distance but tend to change directions. The light also gets reflected at an angle in the interior of the ice. As snow exists as collection of several snowflakes on the ground, the light that falls on them will not have a particular wavelength that is reflected with some regularity. So, most of the light that falls on the snow will almost completely gets reflected back. The light that gets reflected by the snow will remain white most of the time as the total light and not any one wavelength of it is reflected back. Hence, snow is white in color.

CONTOH TEKS EXPLANATION

How Rainbow is Formed
Rainbow is one of  optic phenomena that happens in the atmosphere of the earth naturally. We can see it at mountin range, or  when it is cloudy, or  when it is raining and rising of sun. We have to be the other side for looking.  We  just can see it a half of circle form, but acctually the rainbow is a circle form. We can see it perfectly, if it is seen by standing in the high place. It is real that rainbow is a circle form not like parabola form. On the ground, we can not see perfectly, except if we are in the high place like in the air plane or standing on top of  moutain. When we are looking at rainbow’s colors, we will see them that ordered of red is on the highest order,  and purple is on  the lowest order.
Red is more dominant than another color caused by having biggest wave between others. Therefore the red one is in the highest order  and purple one is in lowest order. How rainbow is formed?  Try to watch it when light of sun concerns a 90-degree angle mirror or a glass prism side, or surface of  soap foam. We can see colors on the light. The light is rayyed to be some  wave lenght of light that it is seen by our eyes as red, bright red, yellow, green, blue and purple. These colors are compnents of light that they are called visible light. The other component is invisible light such as infrared (red is in the right side), and ultraviolet (bright red is in the left side).
So, we can see the beautiful rainbow because there are some processes to be beautiful rainbow that it appears in the sky.

EXPLANATION TEXT

Teks Explanation (Explanation Text)

Posted by Ahmad Fathoni
Explanation text (teks explanation) adalah sebuah teks yang berisi tentang proses-proses yang berhubungan dengan fenomena-fenomena alam, soisal, ilmu pengetahuan, budaya dan lainnya. Sebuah Explanation text biasanya berasal dari pertanyaan penulis terkait ‘why’ dan ‘how’ terhadap suatu fenomena yang ada.




Tujuan Komunikatif Explanation Text

Tujuan komunikatif dari Explanation text adalah untuk menerangkan proses-proses yang terjadi dalam pembentukan atau kegiatan yang terkait dengan fenomena-fenomena alam, sosial, ilmu pengetahuan, budaya, dan lainnya yang bertujuan menjelaskan.

Generic Structur Explanation Text

Terdapat tiga bagian dalam struktur kalimat Explanation Text, yaitu:

1. A general statement
Dalam general statement berisi tentang penjelasan umum tentang fenomena yang akan dibahas, bisa berupa pengenalan fenomena tersebut atau penjelasannya.

2. A squenced of explanation
A squenced of explanation berisi tentang penjelasan proses mengapa fenomena tersebut bisa terjadi atau tercipta. A squenced of explanation berupa jawaban dari pertanyaan ‘why’ dan ‘how’ penulis ketika membuat sebuah Explanation text. Dalam squenced of explanation bisa terdiri lebih dari satu paragrap.

3. Closing
Sebenarnya closing itu tidak tercantum dalam generic structure dari Explanation text, tetapi kebanyakan orang beranggapan bahwa paragrap terakhir dari sebuah Explanation text adalah closing, padahal itu merupakan bagian dari squenced of explantaion yang berisi tentang langkah akhir yang dijelaskan pada bagian squenced of explanation.


Language features Explanation Text

Dalam sebuah explanation text, terdapat ciri-ciri kebahasaan seperti di bawah ini, yaitu:
•    Menggunakan simpel present tense
•    Mengguankan abstract noun (kata benda yang nampak)
•    Mengguanakan Passive voice
•    Menggunakan Action verbs
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