Barometers have been used for almost 400 years to measure pressure changes in the atmosphere. The fi rst known barometer was invented by Evangelista Torricelli (1608-1647), a student of Galileo during his final years in Florence, Italy. The height of a liquid in a barometer is directly proportional to the atmospheric pressure, or
P = ρgh
where P is the pressure, ρ is the density of the barometer fluid, and h is the height of the liquid column. For mercury barometers, the density of the fluid is 13,560 kg/m3. On the surface of the earth, the acceleration due to gravity, g , is approximately 9.8 m/s2. Thus, the only variable in the equation is the height of the fluid column, h , which should have the unit of meters.
(a) Create an anonymous function P that finds the pressure if the value of h is provided. The units of your answer will be
kgm/m3s2(m) = kg 1/ms2 = Pa
(b) Create another anonymous function to convert pressure in Pa (Pascals) to pressure in atmospheres (atm). Call the function Pa_to_atm . Note that 1 atm = 101,325 Pa
(c) Use your anonymous functions to fi nd the pressure for fl uid heights from 0.5 m to 1.0 m of mercury.
(d) Save your anonymous functions as .mat files