S wave
a seismic wave that travels only through solids, vibrating at a right angle to its direction of travel; also called secondary wave
salinity
the amount of salt in water
San Andreas Fault
a deep crack in Earth's crust in California, where the North American Plate and the Pacific Plate slide past each other
sand dune
mounds formed in the desert or on beaches from particles of sand that have been deposited by the wind
sandbar
a formation that is formed when waves deposit sand and cause shallow water to be collected
Santa Ana winds
winds that begin with an area of high air pressure to the north and east of Southern California and flow down through the deserts toward low pressure offshore
scanning electron microscope
the most commonly used electron microscope, which can magnify as much as 300,000 times
scavenger
an animal that seeks out and feeds off of the remains of dead animals
sea breeze
a breeze that develops when cooler, high-pressure air over the water moves in to replace the rising warm air above the land
seafloor spreading
the addition of new rock to plates moving apart under the oceans
secondary consumer
an organism that gets its energy by eating primary consumers
sediment
weathered rock particles
seismic wave
a vibration that travels through Earth and is produced by earthquakes and volcanic eruptions
seismically safe
designed to resist collapsing in the event of an earthquake
seismograph
an instrument that detects, measures, and records the energy of earthquake vibrations at a given location
semimolten
almost melted; used to describe mantle rocks below the lithosphere
sepentine
an unusual rock, found in parts of California's soil layer, containing minerals that are harmful to many plants.
shield volcano
a volcano with broad, gently sloping sides formed by the buildup of layers of lava rocks
simple leaf
a leaf with only one blade
smelting
a process used to melt metal, often for the purpose of separating it into its components
smog
thick clouds of smoke and fog that result from pollutants in the atmosphere
solar energy
any form of energy radiated by the Sun
solar radiation
the electromagnetic energy emitted by the Sun, that shines on Earth's surface
sound wave
a wave produced by the vibration of an object
source
the point of origin of a river or a stream; often occurs in the mountains
stem
the part of a plant that supports leaves and flowers and also transports water and other substances between the roots and leaves.
steppes
the grasslands of central Russia; home to many different animals, such as Siberian chipmunks and wild boars.
stomata
tiny pores of the lower epidermis of a leaf through which gases and water pass
strip mining
a process in which layers of topsoil are peeled away, exposing the coal underneath
subduction
a process that occurs when tectonic plates converge and one plate sinks or slides under the other
subsoil
the layer of soil below the topsoil
surface wave
a seismic wave that is trapped near the surface of Earth
sustainability
the idea that people should fulfill present needs without endangering the ability of future generations to fulfill their needs as well
synthetic
a material that is artificial, or man-made
system
a group of things that work together as a unified whole
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