Thermometer Newton

The atmospheric pressure is measured with an instrument called a barometer, which is also called a closed manometer. When you watch your local weather report, you will often hear the meteorologist discuss the barometric pressure, which is a measure of the force exerted by the atmospheric gases per unit of area. The news often reports pressure in inches of mercury, because a barometer, as are many thermometers, is filled with mercury. The SI unit for pressure is the Pascal, which is derived from Newtons and meters. Other units that are commonly used to measure pressure include the atmosphere (atm), torr, and millimeters of mercury (mm of Hg). You should make sure that you know how to convert between the various units of pressure. The necessary conversion factors are shown here. 

Fahrenheit decided to substitute mercury for the alcohol because its rate of expansion was more constant and could be used over a wider range of temperatures. Fahrenheit, like Isaac Newton before him, realized that it was more accurate to base the thermometer on a substance that changed consistently based on temperature, not simply the hottest or coldest day of the year like the Florentine models. Mercury also had a much wider temperature range than alcohol. This was contrary to the common thought at the time, promoted by Halley as late as 1693, that mercury could not be used for thermometers due to its low coefficient of expansion. 

Figure 3.7 Scatter plot of log-thermometer resistance as a function of temperature and model predicted fit using Eq. (3.83). Starting values were 01 = —5, 02 = 6000, 03 = 344. Model was fit using the Gauss-Newton method within the NLIN procedure in SAS.

Sir Isaac Newton thought the settling [of] the degrees of heat and cold well worth his notice and as he carried everything he meddled [mV] with beyond what anybody had done before him, and generally with a greater than ordinary exactness and precision, so he laid down a method of adjusting thermometers in a more definite way than had been done hitherto. 

Newton used a liquid in glass-thermometer to study heat radiation. Rumford and Leslie used a difierential gas thermometer. Herschel reverted to the liquid thermometer, but this was soon replaced by the thermopile (Melloni [3.4]). Some time later (Langley [3.5]) the first bolometers were used. More recently the use of the gas thermometer, in the shape of the Golay [3.6] and Luft cells has been reintroduced and is now widely used in spectrometers. Another type of thermal detector now widely used is that utilizing the pyroelectric effect. In addition to these, several other detection processes have been suggested, including thermal expansion and changed dielectric properties with temperature. 

German air-raid in the night of 23-4 December 1940, when Joule s barometers and thermometers, a secretaire of Newton s, and a library of 50,000 volumes, were also destroyed. ... 

Torricelli makes the hrst barometer using mercury in a sealed glass tube The Dutch scientist Anton van Feeuwenhoek develops a microscope Isaac Newton invents a reflecting telescope Gabriel Fahrenheit invents an alcohol thermometer (mercury thermometer developed in 1714)... 

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