Rotating Capillary Tube Experiment
Capillary tube with mercury, ruler, plumb line, metre ruler and clamp stand.
1. Measure the length of the air column,(in mm) as a function offrom= 0 to= 180 .can be found by measuring (with the aid of a metre rule and the plumbline)and as defined in the diagram above (Do not use a protractor).
2. Measure the length of the mercury index, a (in mm) .
3. Draw a graph of(in)againstand hence use it to find the atmospheric
pressure(in mm of mercury). (See below for theory).
4. Compare the value of atmospheric pressure found by using this method with the value measured using the Fortin barometer in the corridor.
Theory : From Boyle's Lawwithmm of mercury
Boyle's law become[is another constant]
Compare this with the equation of a straight line
Measure (or calculate) the gradient,and the- intercept,
And so findwhere