The height of the water column is given as a function of the contact
angle (θ), radius of the tube (R), density (ρ) and surface tension (σ)
of the liquid as follows:
h
= 2σcosθ / ρgR
For water in contact with a clean glass, the contact angle is zero, hence
the equation reduces to
h = 2σ / ρgR
For water at 30oC, the surface tension and density are 0.0712
N/m and 995.7 kg/m3 respectively, as noted in the theory page.
For a tube with a radius of 1 mm:
h = 2(0.0712)(106)/(995.7)(9.8)(1)
= 14.6 mm
For a tube with a radius of 10 mm:
h = 2(0.0712)(106)/(995.7)(9.8)(10)
= 1.46 mm
Note that the water rise in the capillary tube decreases with an increase
of the radius of the tube.
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