statistical error is then

Residual

while residual is

hat over the letter ε indicates an observable estimate of an unobservable quantity called ε.

The cgs physical unit for dynamic viscosity is the poise (P), more commonly expressed, particularly in ASTM standards, as centipoise (cP)

Viscosity describes a fluid’s internal resistance to flow and may be thought of as a measure of fluid friction. See Newton’ expression: the constant μ is known as the coefficient of viscosity, the viscosity, the dynamic viscosity, or the Newtonian viscosity.

centrifugal-IFT equilibrium

Interfacial tension of any liquid that gives a shape very close to a cylinder at the equilibrium point, can be estimated using Vonnegut’s expression:

ω : angular velocity; (radians per second, degrees per second, revolutions per second)

Δρ : difference between two fluid: the less-dense and the dense

Since the rotation of the horizontal tube creates a centrifugal force towards the tube walls, the liquid drop starts to be elongated and this elongation stops when the interfacial tension and centrifugal forces are balanced. Values obtained at this equilibrium point are used to estimate surface tension of the particular liquid by using appropriate correlations. A device called “spinning drop tensiometer” is generally utilized for this purpose.

osculating circle

radius of curvature of a curve at a point is the radius of the osculating circle at that point.

how spectrophotometer works

There are two major classes of devices: (1) single beam and (2) double beam. A double beam spectrophotometer compares the light intensity between two light paths, one path containing a reference sample and the other the test sample.

Wikipedia File:Spetrophotometer-en.svg

In short, the sequence of events in a spectrophotometer is as follows:

1. The light source shines into a monochromator.
2. A particular output wavelength is selected and beamed at the sample.
3. The sample absorbs light.

intensity of that particular wavelength (I vs nm) is recorded.