Wave–particle duality operation of chemical reactions. Electricity, first thought to be a fluid, was now understood to consist of particles called electrons. This was first demonstrated by J. J. Thomson in 1897 when, using a cathode ray tube, he found that an electrical charge would travel across a vacuum. Since the vacuum offered no medium for an electric fluid to travel, this discovery could only be explained via a particle carrying a negative charge and moving through the vacuum. This electron flew in the face of classical electrodynamics, which had successfully treated electricity as a fluid for many years (leading to the
Charge (physics) a particular representation of that symmetry; the charge quantum number is then the weight of the representation. Various charge quantum numbers have been introduced by theories of particle physics. These include the charges of the Standard Model: Charges of approximate symmetries: Hypothetical charges of extensions to the Standard Model: In supersymmetry: In conformal field theory: In gravitation: In the formalism of particle theories, charge-like quantum numbers can sometimes be inverted by means of a charge conjugation operator called C. Charge conjugation simply means that a given symmetry group occurs in two inequivalent (but still isomorphic) group representations. It is usually