Spectra-Reunion-FR

  • I- Spectrum

    When the light crosses a surface like  a prism glass, rain , a disk, it's decomposed  in the colors of rainbow (purple, blue, green,yellow,orang,red)

    Prism: the crossing of the light in the prism allows the decoposition of the light

    Rainbow: The water drops of the rain allow the decomposition of the light too

    Spectrum of the light: It's the result of the decomposition of the light

    Disk: We can see the colors because of the reflect of light on the disk

    II-Gaseous spectrum

    A gaseous spectrum allows the indentification of chimicals elements in a gas, it's represented by colors stripes on a black background

      Sodium (Na)

    Mercury(Hg)

     

    III-Absorption spectrum

    An absorption spectrum of a substance is a spectrum got after the crossing  on the substance by the light

    Sodium(Na)

    Mercury(Hg)

    The stripes of gaseous spectra are similar to the stripes of absorption spectrum on a chemical element

    http://www.web-sciences.com/documents/seconde/sedo09/seco09x_fichiers/image014.jpg

    Lithium

    IV-Stars spectrum

    The gaseous and absorptions spectra allow theidentification chimical elements in the star's atmosphere

    Example

    Sun