Zeeman, << ZAY mahn, >> effect is an influence that magnetism has on light. The effect changes the color of the light emitted (sent out) by atoms. Scientists can use the light to measure the strength of the magnetism. The Dutch physicist Pieter Zeeman first observed the effect in 1896.
The parts of an atom that actually emit light are negatively charged particles called electrons. An electron emits light when it jumps from a higher energy level to a lower energy level. The color of the light depends on the difference between the levels. The atoms in a substance will emit light when they are given enough energy—for example, by heating the substance.
You can study the light emitted by a particular kind of atom by using a prism to break the light into different colors. The colors appear as bright lines called spectral lines. The Zeeman effect is the splitting of a single spectral line into two or more lines. This effect occurs when a substance emitting light is placed in a magnetic field. A magnetic field is the influence that a magnet or electric current creates in the region around it.
The Zeeman effect occurs because electrons have magnetism resulting from their charge and motion. The effect occurs when the magnetic fields created by electrons of a particular kind of atom interact with the external magnetic field. Depending on how an electron is oriented, this interaction may increase or decrease the electron’s energy slightly. Each new energy level makes a different spectral line. In this way, a single spectral line splits into two more lines when atoms are in a magnetic field.
