Science terms starting with S

1,372 terms

S 1) South or 2) Snow
S phase The phase in the cell cycle during which DNA synthesis occurs.
S&E See U.S. Department of Agriculture.
S-Band Radar These were in use as network radars in the National Weather Service prior to the installation of the WSR 88-D radars.
S/W Shortwave - a disturbance in the mid or upper part of the atmosphere which induces upward motion ahead of it.
S/WV Shortwave - a disturbance in the mid or upper part of the atmosphere which induces upward motion ahead of it.
S1 mapping A method to characterise post-transcriptional modifications in RNA (removal of introns etc.
S1 nuclease An enzyme obtained from the filamentous fungus Aspergillus oryzae which specifically degrades RNA or single-stranded DNA into its constituent…
saccharide A simple sugar or a more complex compound that can be hydrolyzed to simple sugar units.
saccharifaction Following liquefaction, the hydrolysis of polysaccharides by glucoamylase to maltose and glucose.
saccharification A conversion process using acids, bases, or enzymes in which long-chain carbohydrates are broken down into their component fermentable sugars.
Sacramento Soil Moisture Accounting Model (SACSMA) A hydrologic model which simulates the movement and occurrence of water in and on top of the ground.
Sacred landscapes Natural places recognized by a cultural group as having spiritual or religious significance.
Sacred site Any specific, discrete, narrowly delineated location on federal land that is identified by an Indian tribe, or Indian individual determined to be an…
Sacrificial Anode A metal rod placed in a water heater tank to protect the tank from corrosion. Anodes of aluminum, magnesium, or zinc are the more frequently metals.
Saddle dam A subsidiary dam of any type constructed across a saddle or low point on the perimeter of a reservoir. See dike.
Safe Drinking Water Act (SDWA) The Safe Drinking Water Act (SDWA) ensures that our tap water is fit to drink. Passed in 1974, SDWA sets national drinking water standards for public…
Safe Drinking Water Act (SWDA) Act authorizing development of maximum contaminant levels for drinking water applicable to public water systems (i.e.
Safe harbor The ability of management to discuss in good faith a company's prospects and financial projections with analysts and investors without fearing litigation.
Safe yield The amount of groundwater that can be withdrawn from a groundwater basin over a period of time without exceeding the long-term recharge of the basin or…
Safety Disconnect An electronic (automatic or manual) switch that disconnects one circuit from another circuit.
Safety Evaluation Earthquake (SEE) The earthquake expressed in terms of magnitude and closest distance from the damsite or in terms of the characteristics of the time history of free-field…
Safety evaluation flood (SEF) The largest flood for which the safety of a dam and appurtenant structure(s) are to be evaluated.
Safety Evaluation of Existing Dams (SEED) examination The onsite examination performed initially and at predetermined intervals (approximately every 6 years).
Safety Evaluation of Existing Dams (SEED) report A compilation of independent technical reports that evaluate the design, construction, and performance of a dam for its structural and hydraulic integrity…
SafetyNET Inmarsat-C SafetyNET is an internationally adopted, automated satellite system for promulgating weather forecasts and warnings, marine navigational…
Saffir-Simpson Hurricane Wind Scale The Saffir-Simpson Hurricane Wind Scale is a 1 to 5 categorization based on the hurricane's intensity at the indicated time.
Saffir-Simpson Scale This scale was developed in an effort to estimate the possible damage a hurricane's sustained winds and storm surge could do to a coastal area.
Sahara a large desert in northern Africa.
Sahel a large savanna in northern Africa.
Saline A solution of salt and water.
saline resistance Synonym for salt tolerance.
Saline sodic land Soil that contains soluble salts in amounts that impair plant growth but not an excess of exchangeable sodium.
Saline water Water that contains more than 1,000 milligrams per liter of dissolved solids.
Salinity A measure of the amount of salt and other mineral substances dissolved in water.
Salinity (SAL) In oceanography, conductivity is measured and converted to salinity by a known functional relationship between the measured electrical conductivity of…
Salivary gland (SA-lih-VAYR-ee gland) A gland in the mouth that produces saliva.
Salmonella A genus of rod-shaped, gram-negative bacteria that are a common cause of food poisoning.
Salmonids Family of fish that includes salmon and steelhead.
Salt flat Low-lying ground where salts collect in the soil because of the evaporation of standing water.
Salt Gradient Solar Ponds Consist of three main layers. The top layer is near ambient and has low salt content.
salt tolerance The ability of a plant in soil or in culture to withstand a concentration of common salt (sodium chloride) which is damaging or lethal to most other…
Saltation The movement of sand or fine sediment by short jumps above a streambed under the influence of a water current too weak to keep it permanently suspended in…
Salvage logging The harvest of dead, dying, damaged or weak trees after a forest fire to prevent the spread of disease or insects and to reduce the risk of high intensity…
SAME (Specific Area Message Encoding) - A tone alert system which allows NOAA Weather Radio receivers equipped with the SAME feature to sound an alert for only…
SAMEX Storm and Mesoscale Ensemble Experiment
Sample error Random variation reflecting the inherent variability within a population being counted.
sampling The process of digitizing analog information to identify relevant information.
sampling frequency The rate at which sensor data is read or sampled.
Sand A rock or mineral fragment of any composition that has a diameter ranging from 0.5 to 2.0 mm. Sand has a gritty feel.
Sand backfill Material which has a particle size which varies from a No. 4 sieve to a No. 200 sieve and is used for refilling an excavation.
Sand boil A sand boil is sand and water that come out onto the ground surface during an earthquake as a result of liquefaction at shallow depth.
Sand dune An elongated mound (hill or ridge) of sand accumulated and sorted by the action of wind or water.
Sand dune obligate species Plant or animal species found only in sand dune habitats.
Sandstone Sedimentary rock composed of sand-sized grains (usually quartz) cemented together.
Sandstorm Particles of sand carried aloft by strong wind. The sand particles are mostly confined to the lowest ten feet, and rarely rise more than fifty feet above…
Sanger sequencing A widely used method of determining the order of bases in DNA. See also: sequencing, shotgun sequencing
Sanitary waste Nonhazardous, nonradioactive liquid and solid waste generated by normal housekeeping activities.
Sanitary wastewater Wastewater (includes toilet, sink, shower, and kitchen flows) generated by normal housekeeping activities.
Santa Ana Wind In southern California, a weather condition in which strong, hot, dust-bearing winds descend to the Pacific Coast around Los Angeles from inland desert…
SAP Fluid content of the xylem and phloem cells of plants. Fluid content of the vacuole generally referred to as cell sap.
saprophyte An organism (generally a fungus) that depends on dead plant or animal tissue for its source of nutrition and metabolic energy.
SARA Title III Superfund Amendments and Reauthorization Act of 1986 known as the Emergency Planning and Community Right-to-Know Act of 1986.
Sastrugi Ridges of snow formed on a snow field by the action of the wind.
SAT 1. Satellite (imagery) 2. Saturday
satellite A chromosomal segment that branches off from the rest of the chromosome but is still connected by a thin filament or stalk.
satellite DNA Highly repetitive DNA in plant and animal genomes, consisting of millions of copies of sequences typically in the range 5-500 bp long.
Satellite Hydrology Program A NOHRSC program that uses satellite data to generate areal extent of snow cover data over large areas of the western United States.
satellite RNA A small, self-splicing RNA molecule that accompanies several plant viruses, including tobacco ringspot virus. Synonym: viroid.
Satellite RNA (viroids) A small, self-splicing RNA molecule that accompanies several plant viruses, including tobacco ringspot virus.
SATL Satellite
Saturated steam Steam at the temperature that corresponds to its boiling temperature at the same pressure.
Saturated unit weight The wet unit weight of soil when saturated. See unit weight.
Saturated zone A zone in which all voids are filled with water. The area below the water table where all open spaces are filled with water. See ground water.
Saturation Saturation The condition in which the partial pressure of any fluid constituent (water in the atmospheric air) is equal to its maximum possible partial…
Saturation (and internal vibration) A method of compacting soil using water added to soil and internal vibrators (such as a concrete vibrator) are worked down through the depth of soil…
Saturation Vapor Pressure The vapor pressure of a system, at a given temperature, wherein the vapor of a substance is in equilibrium with a plane surface of that substance's pure…
Savanna A flat grassland of tropical and subtropical regions usually having distinct periods of dry and wet weather.
Sawlog A log meeting minimum commercial requirements of diameter, length, and defect. The usual commercial requirements are a minimum of 8´ long with an inside…
SAWRS Supplementary Aviation Reporting Station - the SAWRS program addresses the concerns of users who depend on weather observations for air operations.
Sawtimber Live trees of commercial species containing at least one 12´ sawlog or two noncontiguous 8´ logs.
SBCAPE Surface Based CAPE; CAPE calculated using a Surface based parcel.
SBND Southbound
SBSD Subside
SC Abbreviation for synaptonemal complex.
SCA Abbreviation for specific combining ability.
Scaffold The central protein aceous core structure of condensed eukaryotic chromosomes. The scaffold is composed of non-histone chromosomal protein s.
Scalar A constant number. 1, -16, .3534, 7346 are all scalars.
Scale Ratio of map distance to Earth distance. Thus, in a 1:24,000 scale map, one centimeter, inch, or foot equals 24,000 centimeters, inches, or feet on the…
Scale Up Conversion of a process, such as fermentation of a micro-organism, from a small laboratory scale to a larger industrial scale.
Scaled sale A type of timber sale contract that specifies measuring or scaling of the included timber after removal.
Scaler An electronic instrument for counting radiation induced pulses from radiation detectors such as a Geiger-Muller tube.
Scaling Prying loose pieces of rock off a face or roof to avoid danger of their falling unexpectedly.
scanning electron microscope (Abbreviation: SEM). An electron-beam-based microscope used to examine, in a three dimensional screen image, the surface structure of prepared specimens.
SCAR Abbreviation for sequence characterized amplified region.
scarification The chemical or physical treatment given to certain seed s having hard, impermeable seed coats in order to puncture or weaken the seed coat sufficiently…
Scarify Loosening topsoil or breaking up the forest floor to improve conditions for seed germination or tree planting.
Scarp See Escarpment
Scatter When refering to photons and light, scattering describes the phenomenon of a source absorbing, and then emanating light in all directions.
Scattered When used to describe precipitation (for example: "scattered showers") - Area coverage of convective weather affecting 30 percent to 50 percent of a…