A substance that dissolves in water with the formation of hydrogen ions and reacts with a base to form a salt and water. It neutralizes alkalis, dissolves some metals, and turns litmus red; typically, a corrosive and sour-tasting liquid.
A substance that dissolves in water with the formation of hydroxyl ions and reacts with an acid to form a salt and water; turns litmus paper blue.
The complete path of an electric current usually including the source of electric energy.
Process by which heat or electricity is transmitted through a material or body without movement of the medium itself.
The rate at which a radioactive isotope disintegrates until a final non-radioactive isotope is formed.
A region associated with a distribution of electric charge or a varying magnetic field, in which forces due to that charge or field, act upon other electric charges.
A kind of radiation including visible light, radio waves, gamma rays and x-rays in which electric and magnetic fields vary simultaneously.
The entire range of wavelengths or frequencies of electromagnetic radiation extending from gamma rays to the longest radio waves and including visible light.
A thermodynamic quantity representing the unavailability of a system's thermal energy for conversion into mechanical work, often interpreted as the degree of disorder or randomness in the system.
Characterized by or formed with liberation of heat.
The splitting of an atomic nucleus resulting in the release of large amounts of energy.
The union of atomic nuclei to form heavier nuclei resulting in the release of enormous quantities of energy.
The gravitational attraction of the mass of the Earth, the moon or a planet for bodies at or near its surface.
Invisible rays just beyond the red end of the visible spectrum. Their waves are longer than those of the spectrum colors but shorter than radio waves, and have a penetrating heating effect; used in cooking and photography.
An atom or group of atoms that carries a positive or negative electric charge as a result of having lost or gained one or more electrons.
Any of two or more species of atoms of a chemical element with the same atomic number and nearly identical chemical behavior, but with differing atomic mass or mass number and different physical properties.
Energy associated with motion.
Combination of a substance with oxygen.
A numerical measure of the acidity or alkalinity of a chemical solution.
The energy that matter has because of its position or because of the arrangement of atoms or parts.
The throwing back by a body or surface of light, heat or sound without absorbing it.
Deflection from a straight path undergone by a light ray or energy wave in passing obliquely from one medium (such as air) into another (such as glass) in which its velocity is different.
The amount of a substance that will dissolve in a given amount of another substance.
Mechanical radiant energy that is transmitted by longitudinal pressure waves in a material medium (such as air) and is the objective cause of hearing.
The rate of change of position and direction with respect to time.
A disturbance or variation that transfers energy progressively from point to point in a medium, and that may take the form of an elastic deformation or of a variation of pressure, electric or magnetic intensity, electric potential, or temperature.