The_Cambridge_Handbook_of_Physics_Formulas

88 Dynamics and mechanics
Surface tension
surface energy
σ lv = (3.335) σ
area
lv surface tension
surface
Definition
(liquid/vapour
surface tension
= (3.336) interface)
length
R 2
(
R 1
Laplace’s
1
formula a ∆p = σ lv + 1 )
∆p pressure difference
over surface
(3.337)
R 1 R 2 R i principal radii of
curvature
( )
Capillary
1/2 2σlv
constant c c =
(3.338)
gρ
Capillary rise
(circular tube)
h = 2σ lv cosθ
ρga
(3.339)
c c
ρ
g
h
θ
a
capillary constant
liquid density
gravitational
acceleration
rise height
contact angle
tube radius
Contact angle cosθ = σ σ wv wall/vapour surface
wv −σ wl
tension
(3.340)
σ lv σ wl wall/liquid surface
tension
a For a spherical bubble in a liquid ∆p =2σ lv /R. For a soap bubble (two surfaces) ∆p =4σ lv /R.
h
a
σ wv
σ wl
θ
θ
σ lv