of volume-values see: Orders of magnitude (volume) Angle Circumferentor Cross staff Goniometer Graphometer Inclinometer Mural instrument Protractor Quadrant Reflecting instruments Octant Reflecting circles Sextant Theodolite and total station Orientation in three-dimensional space See also the section about navigation below. Level Level (instrument) Laser line level Spirit level Direction Gyroscope Mechanics This includes basic quantities found in classical- and continuum mechanics; but strives to exclude temperature-related questions or quantities. Mass- or volume flow measurement Gas meter Mass flow meter Metering pump Water meter Speed or velocity (flux of length) Airspeed indicator LIDAR speed gun Radar speed gun, a Doppler radar device, using the Doppler effect for indirect measurement of velocity. Speedometer Tachometer (speed of rotation) Tachymeter Variometer (rate of climb or descent) Velocimetry (measurement of fluid velocity) For the ranges of speed-values see: Orders of magnitude (speed) Acceleration Accelerometer Mass Balance Check weigher measures precise weight of items in a conveyor line, rejecting underweight or overweight objects. Inertial balance Katharometer Mass spectrometers measure the mass-to-charge ratio, not the mass, of ionised particles. Weighing scale For the ranges of mass-values see: Orders of magnitude (mass) Linear momentum Ballistic pendulum Force (flux of linear momentum) Force gauge Spring scale Strain gauge Torsion balance Tribometer Pressure (flux density of linear momentum) Anemometer (measures wind speed) Barometer used to measure the atmospheric pressure. Manometer (see Pressure measurement and Pressure sensor) Pitot tube (measures airspeed) Tire-pressure gauge in industry and mobility For the ranges of pressure-values see: Orders of magnitude (pressure) Angular velocity or rotations per time unit Stroboscope Tachometer For the value-ranges of angular velocity see: Orders of magnitude (angular velocity) For the ranges of frequency see: Orders of magnitude (frequency) Torque Dynamometer Prony brake Torque wrench Energy carried by mechanical quantities, mechanical work Ballistic pendulum, indirectly by calculation and or gauging Electricity, electronics, and electrical engineering Considerations related to electric charge dominate electricity and electronics. Electrical charges interact via a field. That field is called electric field.If the charge doesn't move. If the charge moves, thus realizing an electric current, especially in an electrically neutral conductor, that field is called magnetic. Electricity can be given a quality — a potential. And electricity has a substance-like property, the electric charge. Energy (or power) in elementary electrodynamics is calculated by multiplying the potential by the amount of charge (or current) found at that potential: potential times charge (or current). (See Classical electromagnetism and Covariant formulation of