Search results
Results from the WOW.Com Content Network
The hydrometer probably dates back to the Greek philosopher Archimedes (3rd century BC) who used its principles to find the density of various liquids. [ 1 ] [ 2 ] An early description of a hydrometer comes from a Latin poem, written in the 2nd century AD by Remnius, who compared the use of a hydrometer to the method of fluid displacement used ...
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.
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 ...
The Baumé scale is a pair of hydrometer scales developed by French pharmacist Antoine Baumé in 1768 to measure density of various liquids. The unit of the Baumé scale has been notated variously as degrees Baumé, B°, Bé° and simply Baumé (the accent is not always present). One scale measures the density of liquids heavier than water and ...
Ultrasonic density meters work on various principles to calculate the density. One of the methods is the transit-time principle (also known as the time of flight principle). With this technique, a sensor is typically installed in the pipe, which has an ultrasonic transmitter and an ultrasonic receiver in one construction.
The Huygens–Fresnel principle provides a reasonable basis for understanding and predicting the classical wave propagation of light. However, there are limitations to the principle, namely the same approximations done for deriving the Kirchhoff's diffraction formula and the approximations of near field due to Fresnel. These can be summarized ...
Hydrostatic bubbles, also known as philosophical bubbles, gravity beads, aerometrical beads and hydrometer beads, are a type of hydrometer invented in 1757 by Alexander Wilson of Glasgow. [1] The design was subsequently improved and patented by the glassblower and instrument maker Isabella Lovi [ 2 ] of Edinburgh in 1805. [ 3 ]
The Helmholtz reciprocity principle describes how a ray of light and its reverse ray encounter matched optical adventures, such as reflections, refractions, and absorptions in a passive medium, or at an interface. It does not apply to moving, non-linear, or magnetic media.