Ever wonder why the sky is blue??????
The question Why the sky is blue? is one of the most often asked questions by young and old people alike. To find the answer, we first have to look up into the sky at the earths atmosphere. If the earth had no atmosphere, the sky above would be black like the darkness of space. The earths atmosphere is mainly composed of the gases nitrogen, oxygen and carbon dioxide as well as other materials like water vapour and dust. These are an important factor in making the sky appear blue. They are also half of the answer to this elusive question. Lets look at the other half.
Let there be light.
To better explain this natural phenomenon, It is important to consider light in more detail. Light is made up of a spectrum of colors. All the colours. All the colours in white light are different red light has a longer wavelength (think of a wavelength as how intense or powerful a colour is), while the shortest wavelength are on the violet end of the spectrum.
Sunlight collides with the elements in the atmosphere and the different wavelengths of light scatter throughout the sky. The colours with shorter wavelengths are scattered more, and, since violet and blue are the shortest wavelengths, the sky should appear violet. However, our eyes are more sensitive to blue light than they are to violet light, so we perceive the sky as blue.
Composed of : (phrasal verb) : to be made or formed from several parts, things or people
Elusive : (adj.) : difficult to find , define or achieve
Phenomenon : (n) : a fact or an event in nature or society, especially one that is not fully understood
Spectrum : (n) : a band of coloured light in order of the wavelengths, as seen in a rainbow and into which a ray of light may be separated
Collide : (v) : if two people, vehicles, etc. collide, they crash into each other
Scatter : (v) : to throw or drop things in different directions
Perceive : (v) : to notice or become aware of something
คำศัพท์ ไม่ยากเท่าไรHoneyBee.....เลยไม่แปลให้นะ : Mr.BJ
edit @ 2007/06/16 10:35:03