Science terms starting with S

1,372 terms

  1. Steam Fog Fog formed when water vapor is added to air which is much colder than the source of the vapor.
  2. Steam plant A plant in which the prime mover is a steam turbine. The steam used to drive the turbine is produced in a boiler where fossil fuels are burned.
  3. Steam Turbine A device that converts high-pressure steam, produced in a boiler, into mechanical energy that can then be used to produce electricity by forcing blades in…
  4. Steam turbine-generator (STG) A device that uses high-pressure steam, produced in a boiler, to drive the blades of a turbine to produce mechanical energy that can then be used to…
  5. Steel factor See stem cell factor.
  6. Steep slopes Ground surface that rises precipitously above the horizon.
  7. Steepness In marine terms, on a buoy report, wave steepness is the ratio of wave height to wave length and is an indicator of wave stability.
  8. Steering Currents Same as Steering Winds; a prevailing synoptic scale flow which governs the movement of smaller features embedded within it.
  9. Steering flow Steering flow A basic fluid flow which exerts a strong influence upon the direction of movement of disturbances embedded in it.
  10. Steering Winds Same as Steering Currents; A prevailing synoptic scale flow which governs the movement of smaller features embedded within it.
  11. stele The central vascular cylinder, inside the cortex, of roots and stems of higher plants.
  12. stem The main body of the above-ground portion of a tree, shrub, herb or other plant; the ascending axis, whether above or below ground, of a plant.
  13. Stem cell A cell from which other types of cells develop. For example, blood cells develop from blood-forming stem cells.
  14. Stem cell antigen 1 (Sca-1) Cell-surface protein on bone marrow cell, indicative of hematopoietic stem cells and mesenchymal stem cells.
  15. Stem cell factor (SCF) Relatively undifferentiated cell that can continue dividing indefinitely, throwing off daughter cells that can undergo terminal differentiation into…
  16. Stem cells cells that have the ability to divide for indefinite periods in culture and give rise to specialized cells.
  17. Stemming Crushed stone, soil, sand, or drill cuttings used to plug the unloaded portion of a drill hole.
  18. Steppe Habitat dominated by shrubs and grasses.
  19. Stepped Leader A faint, negatively charged channel that emerges from the base of a thunderstorm and propagates toward the ground in a series of steps of about 1…
  20. sterile (STER-il) Unable to produce children. Also means free from germs.
  21. sterile room Dedicated space for the carrying out of activities that require sterile conditions.
  22. sterility Complete or partial failure of an individual to produce functional gametes or viable zygotes under a given set of environmental conditions.
  23. sterilize 1. The elimination of micro-organisms, using heat, irradiation, filtration or chemicals. 2.
  24. Steward bottle Flask developed for the growth of cells and tissues in a liquid medium, in which they can be periodically submerged during rotation.
  25. Stewardship Careful and responsible management to ensure that goals and objectives are being achieved for the benefit of current and future generations.
  26. STFR Stratus Fractus
  27. STG See Steam turbine generator
  28. Sticky end A protruding, single-stranded nucleotide se- quence produced when a restriction endonuclease cleaves off center in its recognition sequence.
  29. Sticky limit The lowest moisture content at which a soil will stick to a metal blade drawn across the surface of the soil mass.
  30. stigma Receptive portion of the style, to which pollen adheres.
  31. Still gas Any form or mixture of gases produced in refineries by distillation, cracking, reforming, and other processes.
  32. Stillage The grains and liquid effluent remaining after distillation.
  33. Stilling Basin Concrete portion downstream from conduit, tunnel, or control structure. A pool, usually lined with reinforced concrete, located below a spillway, gate, or…
  34. Stilling pool A pool located below a spillway, gate, or valve into which the discharge dissipates energy to avoid downstream channel degradation.
  35. Stirling Engine A heat engine of the reciprocating (piston) where the working gas and a heat source are independent.
  36. stirred-tank fermenter A growth vessel in which cells or micro-organisms are mixed by mechanically-driven impellers.
  37. STJ Subtropical Jet - this jet stream is usually found between 20° and 30° latitude at altitudes between 12 and 14 km.
  38. STLT Satellite
  39. STM Stratiform
  40. STNRY Stationary
  41. Stochastic Random.
  42. stock A share of stock that represents ownership in the company that issues it. The price of the stock goes up and down, depending on how the company performs…
  43. stock plant The source plant from which cuttings or explants are obtained. Stock plants should be well maintained to optimize explant and cutting quality.
  44. stock solution Pre-prepared solution of commonly used reagents.
  45. Stockpile A storage pile of materials.
  46. Stoichiometric condition That condition at which the proportion of the air-to-fuel is such that all combustible products will be completely burned with no oxygen remaining in the…
  47. Stoichiometric Ratio The ratio of chemical substances necessary for a reaction to occur completely.
  48. Stoichiometry Chemical reactions, typically associated with combustion processes; the balancing of chemical reactions by providing the exact proportions of reactant…
  49. Stolon A lateral stem that grows horizontally along the ground surface. Used by some plant species as a mechanism for dispersal, since stolon nodes can…
  50. stoma (STOH-muh) A surgically created opening from an area inside the body to the outside.
  51. stomatal complex Includes the stoma, together with its guard cells and, when present, any related subsidiary cells.
  52. stomatal index A measurement of the surface density of stoma ta. This parameter has been found useful in comparing leaves of different sizes.
  53. Stone A concretion of earthy or mineral matter; rock.
  54. Stoney gate The fundamental difference between Stoney and fixed-wheel gates is that a moving train of rollers is substituted for the fixed wheels.
  55. Stop codon See Termination codon.
  56. Stoping An upward erosion/piping action into an embankment or foundation (possibly leading to a breach).
  57. Stoplogs Large logs, planks, cut timbers, steel or concrete beams placed on top of each other with their ends held in guides between walls or piers to close an…
  58. Storage The retention of water or delay of runoff either by planned operation, as in a reservoir, or by temporary filling of overflow areas, as in the progression…
  59. Storage Capacity The amount of energy an energy storage device or system can store.
  60. Storage Equation The equation for the conservation of mass.
  61. Storage Hydropower A hydropower facility that stores water in a reservoir during high-inflow periods to augment water during low-inflow periods.
  62. Storage Tank The tank of a water heater.
  63. Storage Water Heater A water heater that releases hot water from the top of the tank when a hot water tap is opened.
  64. Storm Any disturbed state of the atmosphere, especially affecting the Earth's surface, and strongly implying destructive and otherwise unpleasant weather.
  65. Storm Data This National Climatic Data Center (NCDC) monthly publication documents a chronological listing, by states, of occurrences of storms and unusual weather…
  66. Storm Door An exterior door that protects the primary door.
  67. Storm Hydrograph A hydrograph representing the total flow or discharge past a point.
  68. Storm Motion The speed and direction at which a thunderstorm travels.
  69. Storm Relative Measured relative to a moving thunderstorm, usually referring to winds, wind shear, or helicity.
  70. Storm Relative Mean Radial Velocity Map (SRM): This WSR-88D radar product depicts a full 360º sweep of radial velocity data with the average motion of all identified storms subtracted out.
  71. Storm Relative Mean Radial Velocity Regi (SRR): This WSR-88D radar product depicts a 27 nm by 27 nm region of storm relative mean radial velocity centered on a point which the operator can…
  72. Storm Scale Referring to weather systems with sizes on the order of individual thunderstorms. See synoptic scale and mesoscale.
  73. Storm Surge An abnormal rise in sea level accompanying a hurricane or other intense storm, whose height is the difference between the observed level of the sea…
  74. Storm Tide The actual level of sea water resulting from the astronomic tide combined with the storm surge.
  75. Storm Total Precipitation This radar image is an estimate of accumulated rainfall since the last time there was a one-hour, or more, break in precipitation.
  76. Storm Tracking Information This WSR-88D radar product displays the previous, current, and projected locations of storm centroids (forecast and past positions are limited to one hour…
  77. Storm Warning A warning of sustained surface winds, or frequent gusts, in the range of 48 knots (55 mph) to 63 knots (73 mph) inclusive, either predicted or occurring…
  78. Storm Windows Glass, plastic panels, or plastic sheets that reduce air infiltration and some heat loss when attached to either the interior or exterior of existing…
  79. Stormwater Discharge Precipitation that does not infiltrate into the ground or evaporate due to impervious land surfaces but instead flows onto adjacent land or water areas…
  80. stover The dried stalks and leaves of a crop remaining after the grain has been harvested.
  81. STR Strength
  82. Straight-Line Hodograph The name pretty well describes what it looks like on the hodograph. What causes this shape is a steady increase of winds with height (vertical wind shear).
  83. Straight-line Winds Generally, any wind that is not associated with rotation, used mainly to differentiate them from tornadic winds.
  84. Strain A genetic variant within a species.
  85. Stranded Investment (Costs and Benefits) An investment in a power plant or demand side management measures or programs, that become uneconomical due to increased competition in the electric power…
  86. Strata Single, distinct layers of sediment or sedimentary rock.
  87. Strata (stratum) Distinct layers of stratified rock. A layer of sedimentary rock, visually separable from other layers above and below. Layers of rock.
  88. Strategic plan A written plan outlining a government agency's framework for management.
  89. Stratification Layering of a lake, by temperature, during warmer seasons.
  90. Stratified reservoir A reservoir with several thermal layers of water.
  91. Stratiform Having extensive horizontal development, as opposed to the more vertical development characteristic of convection.
  92. Stratiform Rings and Bands These occur between the active convective bands of a hurricane outside of the eye wall.
  93. Stratigraphy Geology that deals with the origin, composition, distribution, and succession of strata. Study or description of layered or stratified rocks.
  94. Stratigraphy (stratigraphic) Layers of sediments and rocks that reflect the geologic history of an area. With respect to cultural resources and archaeological sites, the relative…
  95. Stratocumulus Low-level clouds, existing in a relatively flat layer but having individual elements. Elements often are arranged in rows, bands, or waves.
  96. Stratopause The boundary between the stratosphere and mesosphere.
  97. Stratosphere The region of the atmosphere extending from the top of the troposphere to the base of the mesosphere, an important area for monitoring stratospheric ozone.
  98. Stratospheric Ozone In the stratosphere, ozone has beneficial properties where it forms an ozone shield that prevents dangerous radiation from reaching the Earth's surface.
  99. Stratus A low, generally gray cloud layer with a fairly uniform base. Stratus may appear in the form of ragged patches, but otherwise does not exhibit individual…
  100. stream A body of running water.