Why is the sky blue?

  1. 👍
  2. 👎
  3. 👁
  1. The sky is blue because shorter-wavelngth blue radiation is scattered more by the air than other colors.

    1. 👍
    2. 👎
  2. The sky is blue because light from the sun, which contains all colors, is scattered by the air. It turns out that blue light is scattered more than other colors. If there were no scattering, the sky would be black.

    The molecules in the air scatter all colors of light, but tend to scatter shorter wavelengths more than longer wavelengths. Light is a wave, and the color of the light corresponds to different wavelengths. A rainbow separates light according to wavelength: red, orange, yellow, green, blue, violet. Air molecules are very small, so they scatter light this way, as do very small dust particles and water droplets. This is called Rayleigh scattering, named
    after the physicist John Strutt (Lord Rayleigh) who first explained why the sky is blue.

    Rayleigh scattering is the scattering of a wave from a particle whose diameter is much smaller than the wavelength of the wave. If the wave is a light wave, and the particle is a very small dust particle or water droplet, this condition is satisfied. (It is also satisfied by random density fluctuations in the air, so that the local air acts like the surrounding air with the extra air acting like a particle.)

    You can imagine the electric field in the light wave causing charges in the particle to oscillate. Those oscillating charges radiate light at the same wavelength, but in all directions. This radiated light adds to the light originally passing through. Rayleigh showed that the net effect is the re-radiation of light at "sideways" angles.

    Moreover, he showed that shorter wavelengths (shorter, but still large compared to the molecules) are scattered more strongly. The scattering strength is proportional 1/{fourth power of the wavelength}. This strong wavelength dependence arises from the nature of electric dipole radiation. The wavelength dependence means, for example, that blue light scatters about ten times as strongly as red light.

    Large particles scatter all colors equally well; that is why clouds are white. They consist of large water drops or ice crystals. Likewise, when the sky is hazy, it is white because the particles in the air (aerosols, not molecules) are large and scatter light as clouds do.

    This was originally written by a recent associate whose name I forget.

    1. 👍
    2. 👎

Respond to this Question

First Name

Your Response

Similar Questions

  1. Science

    1.)Why is Earth’s temperature just right for life? (1 point) A.)Earth’s core is hot enough to heat Earth’s surface. B.)Earth’s magnetic field creates suitable temperatures on Earth’s surface. C.)Earth’s crust is warmed

  2. Language Arts

    The Sky Is Low, the Clouds Are Mean This is the poem The sky is low, the clouds are mean, A traveling flake of snow Across a barn or through a rut Debates if it will go. A narrow wind complains all day How some one treated him;

  3. Science

    The sky is mostly blue, with some high, thin, feathery clouds. Which type of weather is most likely to occur? A. Light drizzle,**** B. Heavy precipitation, C. fair weather D. thunderstorm I say A. because the sky is mostly blue.

  4. Language Arts

    "The Sky Is Low, the Clouds Are Mean This is the poem: The sky is low, the clouds are mean, A traveling flake of snow Across a barn or through a rut Debates if it will go. A narrow wind complains all day How some one treated him;

  1. Language arts

    Which of the following lines contains the best examples of alliteration? A)Down he drove into the dreary, Dismal Dungeon B)He forgot to tie his shoes C)A blue moon loomed in a darker blue sky D)He went in the tent and met a friend

  2. Lagarts

    1. There was sky, plenty of sky, all the sky you could want. 2. Day after day it hung like a swath of blue silk, and at night like a black velvet cloak studded with cold jewels. 3. It gave little warmth. 4. And barely any

  3. english

    "Tonight I Can Write" 1. Read the following lines from "Tonight I Can Write." Write, for example, The night is starry and the stars are blue and shiver in the distance. The night wind revolves in the sky and sings. Which of the

  4. English

    Which excerpt from "Foreign Lands" contains hyperbole? A. I saw the next-door garden lie, Adorned with flowers, before my eye, B. Up into the cherry tree Who should climb but little me? C. I held the trunk with both my hands And

  1. english

    In the story told by Outa Karel in “The Little Red Tortoise,” why is the little red tortoise considered a dynamic character? Select all that apply. The Little Red Tortoise 1.He shows different emotions, from being brave to


    The following acid-base indicators are available to follow the titration. Which of them would be most appropriate for signaling the endpoint of the titration? EXPLAIN ------- COLOR CHANGE ------ INDICATOR Acid form Base Form pH

  3. English

    Which of the following phrases from the poem is an example of imagery? A. a poet’s heart B. keep walking C. eight blocks D. blue-gray sky

  4. College Algebra

    A sky diver jumps from a reasonable height above the ground. The air resistance she experiences is proportional to her velocity, and the constant of proportionality is 0.23. It can be shown that the downward velocity of the sky

You can view more similar questions or ask a new question.