Question

Nutrients dissolved in water are carried to upper parts of plants by tiny tubes partlybecause of the capillary effect. determine how high the water solution will rise in atree in a 0.0026-mm-diameter tube as a result of the capillary effect. treat the solutionas water at 20◦c with a contact angle of 15◦c.

Answer 1

The formula for the capillary rise is

h = 2λcosθ/ρgR
where
λ = 0.0728 N/m (surface tension of water)
θ = 15°
ρ = 1000 kg/m³ (density of water)
g = 9.81 m/s²
R = (0.0026 mm/2)(1m/1000 mm) = 1.3×10⁻⁶ m

h = 2(0.0728 N/m)cos15°/(1000 kg/m³)(9.81 m/s²)(1.3×10⁻⁶ m)
h = 11.03 m