Safety engineering is an applied science strongly related to systems engineering and the subset System Safety Engineering. Safety engineering assures that a life-critical system behaves as needed even when pieces fail.

Saltation: The movement of sand or fine sediment by short jumps above the ground or stream bed under the influence of a current too weak to keep it permanently suspended.

Sandblasting: A physical weathering process in which rock is eroded by the impact of sand grains carried by the wind, frequently leading to ventifact formation of pebbles and cobbles.

Sandstone: A detrital sedimentary rock composed of grains from 1/16 to 2 millimeters in diameter, dominated in most sandstones by quartz, feldspar, and rock fragments, bound together by a cement of silica, carbonate, or other minerals or a matrix of clay minerals.

SCALE NODEL:is a representation or copy of an object that is larger or smaller than the actual size of the object . Very often the scale model is smaller than the original and used as a guide to making the object in full size. Scale models are built or collected for many reasons.Engineers who require scale models to test the likely performance of a particular design at an early stage of development without incurring the full expense of a full-sized prototype.

Schist: A metamorphic rock characterized by strong foliation or schistosity.

Schistosity: The parallel arrangement of shaly or prismatic minerals like micas and amphiboles resulting from nonhydrostatic stress in metamorphism.

SCIENCE:refers to any systematic knowledge or practice . In its more usual restricted sense, science refers to a system of acquiring knowledge based on scientific method , as well as to the organized body of knowledge gained through such research.

Scoria: Congealed lava, usually of mafic composition, with a large number of vesicles formed by gases coming out of solution.

Seamount: An isolated tall mountain on the sea floor that may extend more than 1 kilometer from base to peak (see also Guyot).

Sedimentary rock: A rock formed by the accumulation and cementation of mineral grains transported by wind, water, or ice to the site of deposition or chemically precipitated at the depositional site.

Sedimentation: The process of deposition of mineral grains or precipitates in beds or other accumulations. Seif dune: A longitudinal dune that shows the sculpturing effect of cross-winds not parallel to its axis.

Seismicity: The world-wide or local distribution of earthquakes in space and time; a general term for the number of earthquakes in a unit of time.

Stratification: A structure of sedimentary rocks, which have recognizable parallel beds of considerable lateral extent.

Stratigraphy: The science of the description, correlation, and classification of strata in sedimentary rocks, including the interpretation of the depositional environments of those strata.

Stratovolcano: A volcanic cone consisting of both lava and pyroclastic rocks, often conical.

Streak: The fine deposit of mineral dust left on an abrasive surface when a mineral is scraped across it; especially the characteristic color of the dust.

Stromatolite: A fossil form representing the growth habit of an algal mat: concentric spherules, stacked hemispheres, or flat sheets of calcium carbonate and trapped silt encountered in limestones.

Subduction zone: A dipping planar zone descending away from a trench and defined by high seismicity, interpreted as the shear zone between a sinking oceanic plate and an overriding plate.

Sublimation: A phase change from the solid to the gaseous state, without passing through the liquid state.

Submarine canyon: An underwater canyon in the continental shelf.

Subsidence: A gentle epeirogenic movement where a broad area of the crust sinks without appreciable deformation.

Supersaturation: The unstable state of a solution that contains more solute than its solubility allows.

Swash: The landward rush of water from a breaking wave up the slope of the beach.

Swell: An oceanic water wave with a wavelength on the order of 30 meters or more and a height of perhaps 2 meters or less that may travel great distances from its source.

Symbiosis: The interaction of two mutually supporting species that do not compete with or prey upon each other.

Syncline: A large fold whose limbs are higher than its center; a fold with the youngest strata in the center.