Spectroscopy Demonstrations

Activity:
Students are given spectroscopes or gratings and shown various emission spectra

Science Standards:
Nature of Science, Energy & Matter, and Scientific Models (Conceptual)

Objectives:

  • The student will observe that electrically charged, rarefied gas emits photons.
  • The student will observe the light can be separated into a spectrum.
  • The student will identify the composition of gases using a spectrum chart.
  • Materials:

  • Various vacuum gas spectral tubes
  • spectral tube power supplies
  • student spectroscopes or gratings
  • emission spectrum charts



  • Introduction:
    The only information that astronomers receive from the stars is that light that we passively receive. This light carries an enormous amount of information regarding the star's temperature, composition, magnetic fields, and motion. This information is decoded by splitting the light into a spectrum using a spectroscope. As electrons change energy levels, the emit (or absorb) photons of particular and predictable frequencies. The bright line spectrum that results is often called an emission spectrum or a characteristic spectrum. Every atom has an individual and characteristic spectrum, much like every student has a personal fingerprint, that is identifiable.

    Directions:
    1. Demonstrate a hydrogen spectrum, note the colors and positions of lines.
    2. Demonstrate a helium spectrum, it is more complex because of more electrons.
    3. Demonstrate other rarefied gases and identify using a spectral chart.