Spectroscopy how does it work

Sign up for our Newsletter! Mobile Newsletter banner close. Mobile Newsletter chat close. Mobile Newsletter chat dots. Mobile Newsletter chat avatar. Mobile Newsletter chat subscribe. Prev NEXT. Physical Science. By: William Harris. In this simple image of an atom, you can see the electrons existing in separate orbits as Bohr envisioned. An atom absorbs energy in the form of heat, light or electricity.

Electrons may move from a lower-energy orbit to a higher-energy orbit. Cite This! Print Citation. Try Our Crossword Puzzle! What Is the Missing Number? The spectroscopy of optical light produces the familiar rainbow. Spectroscopy is the technique of splitting light or more precisely electromagnetic radiation into its constituent wavelengths a spectrum , in much the same way as a prism splits light into a rainbow of colours.

The energy levels of electrons in atoms and molecules are quantised, and the absorption and emission of electromagnetic radiation only occurs at specific wavelengths. Electrons fall down to lower rungs, emitting light at the specific energy of the difference between the rungs. This allows different atoms to emit different colors of light.

All elements absorb and emit specific wavelengths of light that correspond to those energy levels. An absorption spectrum is a spectrum of light transmitted through a substance, showing dark lines or bands where light has been absorbed by atoms, causing a dip in the spectrum.

An emission spectrum is made by electrons falling down the energy ladder. This heating moves the electrons up the ladder, then when they fall down the ladder some of the light they emit comes to you. This results in bright, colored spikes due to atoms releasing light at those wavelengths. A spectrograph passes light coming into the telescope through a tiny hole or slit in a metal plate to isolate light from a single area or object. This light is bounced off a special grating, which splits the light into its different wavelengths just like a prism makes rainbows.

The split light lands on a detector, which records the spectrum that is formed. Below are examples of the many spectroscopic findings from Hubble. An image tells us what something looks like; a spectrum tells us what it is. What Is a Spectrum? This diagram illustrates how Hubble Space Telescope spectral observations were used to study the chemical makeup of the Southern Crab Nebula.