Complementary experiments
Encyclopedia
In physics
, two experimental techniques are often called complementary if they investigate the same subject in two different ways such that two different (ideally non-overlapping) properties or aspects can be investigated. For example, X-ray scattering and neutron scattering
experiments are often said to be complementary because the former reveals information about the electron
density of the atoms in the target but gives no information about the nuclei
(because they are too small to affect the X-rays significantly), while the latter allows you to investigate the nuclei of the atoms but cannot tell you anything about their electron hulls (because the neutron
s, being neutral, do not interact with the charged
electrons).
Scattering
experiments are sometimes also called complementary when they investigate the same physical property of a system from two complementary
view points in the sense of Bohr
. For example, time-resolved and energy-resolved experiments are said to be complementary. The former uses a pulse which is well defined in time (its position is well known at a given time). The latter uses a monochromatic pulse well defined in energy (its frequency is well known).
Physics
Physics is a natural science that involves the study of matter and its motion through spacetime, along with related concepts such as energy and force. More broadly, it is the general analysis of nature, conducted in order to understand how the universe behaves.Physics is one of the oldest academic...
, two experimental techniques are often called complementary if they investigate the same subject in two different ways such that two different (ideally non-overlapping) properties or aspects can be investigated. For example, X-ray scattering and neutron scattering
Neutron scattering
Neutron scattering,the scattering of free neutrons by matter,is a physical processand an experimental technique using this processfor the investigation of materials.Neutron scattering as a physical process is of primordial importance...
experiments are often said to be complementary because the former reveals information about the electron
Electron
The electron is a subatomic particle with a negative elementary electric charge. It has no known components or substructure; in other words, it is generally thought to be an elementary particle. An electron has a mass that is approximately 1/1836 that of the proton...
density of the atoms in the target but gives no information about the nuclei
Atomic nucleus
The nucleus is the very dense region consisting of protons and neutrons at the center of an atom. It was discovered in 1911, as a result of Ernest Rutherford's interpretation of the famous 1909 Rutherford experiment performed by Hans Geiger and Ernest Marsden, under the direction of Rutherford. The...
(because they are too small to affect the X-rays significantly), while the latter allows you to investigate the nuclei of the atoms but cannot tell you anything about their electron hulls (because the neutron
Neutron
The neutron is a subatomic hadron particle which has the symbol or , no net electric charge and a mass slightly larger than that of a proton. With the exception of hydrogen, nuclei of atoms consist of protons and neutrons, which are therefore collectively referred to as nucleons. The number of...
s, being neutral, do not interact with the charged
Electric charge
Electric charge is a physical property of matter that causes it to experience a force when near other electrically charged matter. Electric charge comes in two types, called positive and negative. Two positively charged substances, or objects, experience a mutual repulsive force, as do two...
electrons).
Scattering
Scattering
Scattering is a general physical process where some forms of radiation, such as light, sound, or moving particles, are forced to deviate from a straight trajectory by one or more localized non-uniformities in the medium through which they pass. In conventional use, this also includes deviation of...
experiments are sometimes also called complementary when they investigate the same physical property of a system from two complementary
Complementarity (physics)
In physics, complementarity is a basic principle of quantum theory proposed by Niels Bohr, closely identified with the Copenhagen interpretation, and refers to effects such as the wave–particle duality...
view points in the sense of Bohr
Niels Bohr
Niels Henrik David Bohr was a Danish physicist who made foundational contributions to understanding atomic structure and quantum mechanics, for which he received the Nobel Prize in Physics in 1922. Bohr mentored and collaborated with many of the top physicists of the century at his institute in...
. For example, time-resolved and energy-resolved experiments are said to be complementary. The former uses a pulse which is well defined in time (its position is well known at a given time). The latter uses a monochromatic pulse well defined in energy (its frequency is well known).