GLOSSARY - Archaeological Chemistry - page 525

wavelength The distance between successive wave crests or wave valleys in all
forms of waves , whether electromagnetic or sound waves ; see frequency .
waves, electromagnetic A form of energy that propagates through space or matter
in the form of transversal waves resulting from the oscillation of an electric field
and a magnetic field at right angles to one another.
waves, micro Electromagnetic radiation with wavelengths ranging between 1 × 10 −3

and 0.1 m.
waves, radio Electromagnetic radiation having wavelengths longer than 0.1 m.
waves, ultrasound Sound waves of very high frequency that are often used for
imaging and nondestructive resting .
wax One of a number of natural materials of either mineral , vegetable, or animal
origin, such as bitumen , rosin , and beeswax , which are brittle solids at ambient tem-
peratures but soften, become pliable, and can be easily molded when warm.
wax printing See batik , encaustic .
weak acid See acid .
weathering The decay of materials caused by their exposure to the environment ;
weathering may be caused by either physical or chemical processes.
weathering, chemical The weathering of materials into others as a result of chemical
reactions occurring on exposure to the environment ; see decay , diagenesis .
weathering, physical The weathering of solid matter into smaller pieces caused by
eroding fluids, such as air and water and the disrupting effects of climatic changes
such as freezing.
weave The interlacing of warp and weft that forms textile fabrics ; in a plain weave , for
example, each weft yarn passes successively over and under single warp yarns in
alternating rows; see weaving .
weaving The technology of making cloth by interlacing, in a loom , usually two (but
sometimes more) sets of yarn , one known as the weft and the other set known as
the warp , in a direction perpendicular to the weft; see weave .
weft The yarn in woven textile s, also known as woof , that run across the length of
woven fabrics ; see weaving .
welding The process of joining two or more metal parts by applying heat, pressure,
or both, with or without a filler metal ; the parts are thus joined by either fusing or
forging .
welding, forge The process for joining two or more metal parts by striking (ham-
mering) or pressing; when carried out by hammering, the process is also known
as hammer welding .
welding, hammer See welding , forge .
wetland The land of marshes, ponds, wet meadows and bogs , that is inundated by
water for varying periods of time during each year and supports vegetation which
is adapted to saturated soil conditions.