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The hydrometer makes use of Archimedes' principle: a solid suspended in a fluid is buoyed by a force equal to the weight of the fluid displaced by the submerged part of the suspended solid. The lower the density of the fluid, the deeper a hydrometer of a given weight sinks; the stem is calibrated to give a numerical reading.
The Fahrenheit hydrometer is a device used to measure the density of a liquid. It was invented by Daniel Gabriel Fahrenheit (1686–1736), better known for his work in thermometry . The Nicholson hydrometer , after William Nicholson (1753-1815), is similar in design, but instead of a weighted bulb at the bottom there is a small container ...
A hygrometer is an instrument which measures the humidity of air or some other gas: that is, how much of it is water vapor. [1] Humidity measurement instruments usually rely on measurements of some other quantities such as temperature, pressure, mass, and mechanical or electrical changes in a substance as moisture is absorbed.
Heat transfer is the natural process of moving energy to or from a system, other than by work or the transfer of matter. In a diathermal system, the internal energy can only be changed by the transfer of energy as heat: Δ U s y s t e m = Q . {\displaystyle \Delta U_{\rm {system}}=Q.}
The operational principles of the ratio pyrometers were developed in the 1920s and 1930s, and they were commercially available in 1939. [ 9 ] As the ratio pyrometer came into popular use, it was determined that many materials, of which metals are an example, do not have the same emissivity at two wavelengths. [ 12 ]
In principle, thermometers made of different material (e.g., coloured alcohol thermometers) might be expected to give different intermediate readings due to different expansion properties; in practice the substances used are chosen to have reasonably linear expansion characteristics as a function of thermodynamic temperature, and so give ...
JOHANNESBURG (Reuters) -U.S. President Donald Trump's attacks on what he alleges is South Africa's mistreatment of its white minority are being met with mockery on social media by some white South ...
A heat meter, thermal energy meter or energy meter is a device which measures thermal energy provided by a source or delivered to a sink, by measuring the flow rate of the heat transfer fluid and the change in its temperature between the outflow and return legs of the system.