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A measuring cup, a common instrument used to measure volume. Buoyant weight (solids) Eudiometer, pneumatic trough (gases) Flow measurement devices (liquids) Graduated cylinder (liquids) Measuring cup (grained solids, liquids) Overflow trough (solids) Pipette (liquids) If the mass density of a solid is known, weighing allows to calculate the volume.
The hourglass is often used as a symbol representing the passage of time. Clocks; a watch-maker seated at his workbench. Chronometry [a] or horology [b] (lit. ' the study of time ') is the science studying the measurement of time and timekeeping. [3]
Ascent rate times ascent time yields the ceiling height. A disdrometer is an instrument used to measure the drop size distribution and velocity of falling hydrometeors. Rain gauges are used to measure the precipitation which falls at any point on the Earth's landmass.
The idea of using atomic transitions to measure time was first suggested by the British scientist Lord Kelvin in 1879, [204] although it was only in the 1930s with the development of magnetic resonance that there was a practical method for measuring time in this way. [205] A prototype ammonia maser device was built in 1948 at NIST. Although ...
In the International System of Units (SI), the unit of time is the second (symbol: s). It has been defined since 1967 as "the duration of 9 192 631 770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium 133 atom", and is an SI base unit. [12]
Instruments come in three main varieties: short period, long period and broadband. The short and long period measure velocity and are very sensitive, however they 'clip' the signal or go off-scale for ground motion that is strong enough to be felt by people. A 24-bit analog-to-digital conversion channel is commonplace.
A nephoscope is a 19th-century instrument for measuring the altitude, direction, and velocity of clouds, using transit-time measurement. This is different from a nephometer, which is an instrument used in measuring the amount of cloudiness.
Historically, the definition of a scientific instrument has varied, based on usage, laws, and historical time period. [1] [2] [3] Before the mid-nineteenth century such tools were referred to as "natural philosophical" or "philosophical" apparatus and instruments, and older tools from antiquity to the Middle Ages (such as the astrolabe and pendulum clock) defy a more modern definition of "a ...