Science terms starting with W

301 terms

W West
w/v Abbreviation for weight per volume. The relative proportions of solid and liquid in a solution.
WAA Warm Air Advection - the advection (movement) of warm air into a region.
Wafer A thin sheet of semiconductor (photovoltaic material) made by cutting it from a single crystal or ingot.
Wake The region of turbulence immediately to the rear of a solid body caused by the flow of air over or around the body.
Wake effect Enhanced plume dispersion due to mechanical turbulence and zones of turbulent eddies, primarily downwind of a building, which results in increased…
walking See: chromosome walking; primer walking.
Wall A vertical structural element that holds up a roof, encloses part or all of a room, or stands by itself to hold back soil.
Wall Cloud A localized, persistent, often abrupt lowering from a rain-free base. Wall clouds can range from a fraction of a mile up to nearly five miles in diameter…
Wall friction Frictional resistance mobilized between a wall and the soil or rock in contact with the wall.
Wall Orientation The geographical direction that the primary or largest exterior wall of a building faces.
wall pressure Pressure that a cell wall exerts against the turgor of the cell contents. Wall pressure is equal and opposite to the turgor potential.
Warm Advection Transport of warm air into an area by horizontal winds. Low-level warm advection sometimes is referred to (erroneously) as overrunning.
Warm Core Low A low pressure area which is warmer at its center than at its periphery. Tropical cyclones exhibit this temperature pattern.
Warm Front A transition zone between a mass of warm air and the colder air it is replacing.
Warm Occlusion A frontal zone formed when a cold front overtakes a warm front and, finding colder air ahead of the warm front, leaves the ground and rises up and over…
Warm Sector A region of warm surface air between a cold front and a warm front.
Warm-water fishery Generally, water or water system that has an environment suitable for species of fish other than salmonids.
Warning The fourth of five Early Warning System components consisting of the processes (including the media) and equipment necessary to make the public aware of…
Warning stage The depth of water in a river at which the National Weather Service (NWS) reviews basin conditions for potential flooding.
Warning time (WT) The amount of time between detection of failure or incipient failure and arrival of dam failure flood.
Wasatch Wind A strong easterly wind blowing out of the mouths of the canyons of the Wasatch Mountains onto the plains of Utah. Also called canyon wind.
Wash A normally dry stream bed that occasionally fills with water.
Wash load That part of the total sediment discharge which is composed of particle sizes finer than those found in appreciable quantities in the bed material, and is…
wash-out The loss of the slower growing micro-organism when two organisms are being grown together.
Waste Digging, hauling and dumping of valueless material to get it out of the way; or the valueless material itself.
Waste management Procedures, physical attributes, and support services that collectively provide for the identification, containerization, storage, transport, treatment…
Waste minimization Actions, policies, or procedures that collectively serve to reduce the amount of wastes generated as a result of operation of an activity or facility.
Waste streams Unused solid or liquid by- products of a process.
Wastebank A bank made of excess or unstable material excavated from a construction site.
Wastewater Water that typically contains less than 1% concentration of organic hazardous waste materials.
Watch A watch is used when the risk of a hazardous weather or hydrologic event has increased significantly, but its occurrence, location, and/or timing is still…
Watch Box (or simply "Box") - slang for a Severe Thunderstorm Watch or Tornado Watch issued by the SPC.
Watch Cancellation This product will be issued to let the public know when either a Tornado Watch or Severe Thunderstorm Watch has been canceled early.
Watch Redefining Statement This product tells the public which counties/parishes are included in the watch.
Watch Status Reports This product lets the NWFO know of the status of the current severe weather watch (Tornado or Severe Thunderstorm).
Water budget (water balance model) An analytical tool whereby the sum of the system inflows equals the sum of the system outflows.
Water code A type of legislation that is specific to the management of water resources.
Water content See moisture content.
Water conveyance efficiency Ratio of the volume of irrigation water delivered by a distribution system to the water introduced into the system.
Water conveyance structure Any structure that conveys water from one location to another.
Water cycle The movement of water from the air to and below the Earth's surface and back into the air. See hydrologic cycle.
Water delivery system Reservoirs, canals, ditches, pumps, and other facilities to move water.
Water demand Water requirements for a particular purpose, as for irrigation, power, municipal supply, plant transpiration or storage.
Water Equivalent The amount of water, in inches, obtained by melting a snow sample.
Water hammer (hydraulic transient) Refers to pressure fluctuations caused by a sudden increase or decrease in flow velocity, usually associated with a rapid closure or opening of a valve in…
Water holding capacity Amount of soil water available to plants. See available capacity. The smallest value to which the moisture content of a soil can be reduced by gravity…
Water Jacket A heat exchanger element enclosed in a boiler. Water is circulated with a pump through the jacket where it picks up heat from the combustion chamber after…
Water management plan A plan developed during construction to help assure water quality compliance for both point and nonpoint pollution sources.
Water Measurement Manual The Bureau of Reclamation's Water Measurement Manual is available on line at the Water Resources Research Laboratory's website.
Water Pollution The alteration of the constituents of a body of water by man to such a degree that the water loses its value as a natural resource.
water potential The pressure gradient that induces the flow of water, particularly with reference to plant water uptake from the soil, comprising the net effects of…
Water purveyor An agency or person that supplies water.
Water quality A term used to describe the chemical, physical, and biological characteristics of water, usually with respect to its suitability for a particular purpose.
Water right A legal entitlement of an individual or entity to extract water from a water source (surface water or groundwater) and to use it for a beneficial use (e.g.
Water saturation That point at which a material will no longer absorb water.
Water sky Water sky The dark appearance of the underside of a cloud layer when it is over a surface of open water.
water soaked See: vitrified.
Water Source Heat Pump A type of (geothermal) heat pump that uses well (ground) or surface water as a heat source.
water stress Occurs when plants are unable to absorb enough water to replace that lost by transpiration. Short-term water stress leads to turgor loss (wilting).
Water supplier A person who owns or operates a public water system.
Water Supply Outlook A seasonal volume forecast, generally for a period centered around the time of spring snowmelt (e.g., April-July).
Water Supply Outlook (ESS) Product A public product issued by a Forecast Office which contains narrative and numeric information on current and extended water supply conditions.
Water surface elevation (stage) The elevation of a water surface above or below an established reference level, such as sea level. See datum.
Water Table The upper level of ground water; the level below which soil and rock are saturated with water.
Water transfers Selling or exchanging water or water rights among individuals or agencies. Artificial conveyance of water from one area to another.
Water Turbine A turbine that uses water pressure to rotate its blades; the primary types are the Pelton wheel, for high heads (pressure); the Francis turbine, for low…
Water user Any individual, district, association, government agency, or other entity that uses water supplied from a Reclamation project.
Water Vapor The most abundant greenhouse gas, it is the water present in the atmosphere in gaseous form.
water vapor path A measure of the total amount of water vapor present in the column. A retrieved quantity from the microwave radiometer.
Water Vapor Plume This appears in the water vapor satellite imagery. It is a plume-like object that extends from the Intertropical Convergence Zone (ITCZ) northward or…
Water Wall An interior wall made of water filled containers for absorbing and storing solar energy.
Water Wheel A wheel that is designed to use the weight and/or force of moving water to turn it, primarily to operate machinery or grind grain.
Water Year The time period form October 1 through September 30.
Water year (WY) Period of time beginning October 1 of one year and ending September 30 of the following year and designated by the calendar year in which it ends.
Water-cooled vibrating grate A boiler grate made up of a tuyere grate surface mounted on a grid of water tubes interconnected with the boiler circulation system for positive cooling.
Watercourse Any surface flow such as a river, stream, or tributary.
Watermaster In Oregon, an official of the Water Resources Department who allocates available surface or groundwater in the state.
Watershed All land area from which run-off water may enter a pond or lake.
Watershed (drainage area) Surface drainage area above a specified point on a stream. Area which drains into or past a point.
Watershed divide The divide or boundary between catchment areas (or drainage areas).
Waterspout In general, a tornado occurring over water. Specifically, it normally refers to a small, relatively weak rotating column of air over water beneath a Cb or…
Waterstage recorder A motor-driven (spring wound or electric) instrument for monitoring water surface elevation.
Waterstop A strip of metal, rubber or other material used to prevent leakage through joints between adjacent sections of concrete.
Waterstop (water bar) A continuous strip of waterproof material placed at concrete joints designed to control cracking and limit moisture penetration.
Watt The rate of energy transfer equivalent to one ampere under an electrical pressure of one volt. One watt equals 1/746 horsepower, or one joule per second.
Watt (W) The unit of electrical power equal to 1 ampere under a pressure of one volt. A Watt is equal to 1/746 horsepower.
Watt hour(Wh) An electrical energy unit of measure equal to one watt of power supplied to, or taken from, an electrical circuit steadily for one hour.
Watt-hour A unit of electricity consumption of one Watt over the period of one hour.
Watthour (Wh) The electrical energy unit of measure equal to 1 watt of power supplied to, or taken from, an electric circuit steadily for one hour.
Wattmeter A device for measuring power consumption.
Wave Crest The highest part of a wave
Wave Form The shape of the phase power at a certain frequency and amplitude.
Wave Height Distance from wave trough to wave crest.
Wave Period Time, in seconds, between the passage of consecutive wave crests past a fixed point.
Wave Power The concept of capturing and converting the energy available in the motion of ocean waves to energy.
Wave runup Vertical height above the sill water level to which water from a specific wave will run up the face of a structure or embankment.
Wave Spectrum The distribution of wave energy with respect to wave frequency or period. Wave spectra assist in differentiating between wind waves and swell.
Wave Steepness The ratio of wave height to wavelength and is an indicator of wave stability. When wave steepness exceeds a 1/7 ratio; the wave typically becomes unstable…
Wave Trough The lowest part of the wave.