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taxis

(Encyclopedia)taxis tăkˈsĭs [key], movement of animals either toward or away from a stimulus, such as light (phototaxis), heat (thermotaxis), chemicals (chemotaxis), gravity (geotaxis), and touch (thigmotaxis). ...

pendulum

(Encyclopedia)pendulum, a mass, called a bob, suspended from a fixed point so that it can swing in an arc determined by its momentum and the force of gravity. The length of a pendulum is the distance from the point...

tropism

(Encyclopedia)tropism trōpˈĭzəm [key], involuntary response of an organism, or part of an organism, involving orientation toward (positive tropism) or away from (negative tropism) one or more external stimuli. ...

siphon

(Encyclopedia)siphon sīˈfən, –fŏn [key], tube or other enclosed conduit through which a liquid is lifted over an elevation and then emptied at a lower level. The movement of the liquid is driven primarily by ...

standpipe

(Encyclopedia)standpipe, tank or pipe for holding water in an elevated position to create pressure in a water supply system. For a tall building, where the pressure from the mains at street level is insufficient to...

Delaware and Hudson Canal

(Encyclopedia)Delaware and Hudson Canal dĕlˈəwâr, –wər [key], former waterway, 108 mi (174 km) long, between Honesdale, Pa., and Eddyville, N.Y. (now in Kingston), linking the Delaware and Hudson rivers; bui...

Delaware Aqueduct

(Encyclopedia)Delaware Aqueduct dĕlˈəwâr, –wər [key], SE N.Y., 85 mi (137 km) long, carrying water from the Rondout Reservoir, Sullivan co., SE into the New York City water system at the Hillview Reservoir, ...

weight

(Encyclopedia)weight, measure of the force of gravity on a body (see gravitation). Since the weights of different bodies at the same location are proportional to their masses, weight is often used as a measure of m...

free fall

(Encyclopedia)free fall, in physics, the state of a body moving solely under the influence of gravitational forces (see gravitation). A body falling freely toward the surface of the earth undergoes an acceleration ...

equilibrium

(Encyclopedia)CE5 Equilibrium equilibrium, state of balance. When a body or a system is in equilibrium, there is no net tendency to change. In mechanics, equilibrium has to do with the forces acting on a body. ...