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Weak Acid
Substances capable of donating hydrogen but do not completely ionize in solution.
Weak Anthropic Principle
The conditions necessary for the development of intelligent life will be met only in certain regions that are limited in space and time.
Weak Bases
Substances capable of accepting hydrogen but do not completely ionize in solution.
Weak Electrolyte
A weak electrolyte is a solute that incompletely dissociates into ions in solution.
Weak Force
The force responsible for beta decay. This force occurs through the exchange of the W and Z0 particles.
Weak Inequality
An inequality that permits the equality case. For example, a is less than or equal to b.
Weak Interaction
The interaction responsible for all processes in which flavour changes, hence for the instability of heavy quarks and leptons, and particles that contain them.
Weak Ligand
A ligand that causes a small crystal field splitting which results in a high-spin complex.
Weakly Ionized Plasma
A plasma in which only a small fraction of the atoms are ionized.
Wear
The loss of material from a surface, generally occurring between two surfaces in relative motion, and resulting from mechanical or chemical action or a combination of both.
Wear Debris
Particles that are detached from machine surfaces as a result of wear and corrosion.
Wear Inhibitor
An additive which protects the rubbing surfaces against wear, particularly from scuffing, if the hydrodynamic film is ruptured.
Wear Pattern
A pattern of wear visible at the point where two parts touch.
Weathering
The action of wind, temperature changes, chemicals and water that breaks the surface of rocks into smaller particles.
Weber
The weber is the SI unit of magnetic flux.
Weber-Fechner Law
An approximate psychophysical law relating the degree of response or sensation of a sense organ and the intensity of the stimulus.
Weber′s Theory
A theory of magnetism which assumes that all magnetic material is composed of many tiny magnets.
Weblinks
Lists all the Weblinks referenced in the Encyclopaedia
Week
Traditional unit of time equal to seven days.
Weft
The yarns running perpendicular to the warp in a woven fabric.
Weibull Distribution
A distribution used for random variables which are constrained to be greater or equal to 0.
Weight
The support force needed to maintain an object at rest relative to a reference system.
Weight Flow Rate
Mass flow rate multiplied by gravity.
Weight Percent
To calculate the mass percent or weight percent of a solution, you must divide the mass of the solute by the mass of the solution (both the solute and the solvent).
Weight to Power Ratio
The weight of a machine divided by the output power of the machine.
Weighted Equivalent Continuous Perceived Noise Level
A measure proposed by International civil aviation organization to assess the continuous exposure to long-term noise of multiple aircraft.
Weightlessness
Sometimes termed "zero g", it is the condition when no force (such as weight) is sensed.
Weiss Constant
A characteristic constant dependent on the material, used in calculating the susceptibility of paramagnetic materials.
Weld
Join two pieces of metal together by heating until fusion of material with or without filler metal.
Weld Bead
A weld deposit resulting from a pass.
Weld Gauge
A device designed for checking the shape and size of welds.
Weld Metal
That portion of a weld that has been melted during welding.
Weld Symbol
A picture used to indicate the desired type of weld.
Weldability
The capacity of a material to form a strong bond of adherence under pressure or when solidifying from a liquid.
Welder Certification
Certification in writing that a welder has produced welds meeting prescribed standards.
Welder Performance Qualification
The demonstration of a welders ability to produce welds meeting prescribed standards.
Welding
The process of joining two pieces of metal together by hammering, pressure or fusion.
Welding Pressure
The pressure exerted during the welding operation on the parts being welded.
Welding Rod
Filler metal in wire or rod form, used in gas welding and brazing processes and in those arc welding processes in which the electrode does not provide the filler metal.
Welding Tip
The tip of a gas torch especially adapted to welding.
Welding Torch
A device used in gas welding and torch brazing for mixing and controlling the flow of gases.
Welding Transformer
A device for providing current of the desired voltage.
Weldment
An assembly whose component parts are formed by welding.
Well
A pit or hole sunk into the earth to reach a supply of water.
Wentworth-Udden Particle Scale
A common system of grading the size of grains in a rock or sediment.
Weston Cell
A voltaic cell that is used as a reference emf.
Westwork
In German Romanesque, a monumental entrance to a church consisting of porches and towers, with a chapel above.
Wet
To come in contact with a fluid.
Wet Bulb Depression
The difference between the dry-bulb temperature and the wet bulb temperature.
Wet Bulb Temperature
The temperature at which water, by evaporating into air, can bring the air to saturation at the same temperature.
Wet Bulb Thermometer
A wet wick is placed over a standard thermometer and air is blown across the surface. The temperature depends on how much moisture is in the air.
Wet Clutch
A clutch immersed in a cooling lubricating fluid, which also keeps the surfaces clean and gives smoother performance and longer life.
Wet Layup
The application of resin to dry reinforcement in the mould.
Wet Scrubber
A vessel used for removing pollutants from a gas stream by means of a liquid spray, liquid jet, or liquid layer.
Wet Strength
Breaking strength of paper saturated with water.
Wet Sump
An engine lubrication system where the oil sits in the sump under the crank, is pumped around the engine and drains back to the sump.
Wetting
Covering with a surface with thin film of liquid.
Wetting Agent
A surface-active agent that promotes wetting by decreasing the cohesion within a liquid.