Thermodynamics

Thermodynamics States About Energy Conversion Thermodynamics is the branch of science that embodies the principles of energy transformation in macroscopic systems. The general restrictions which experience has shown to apply to all such transformations are known as the laws of thermodynamics. These laws are primitive; they cannot be derived from anything more basic. The first law of thermodynamics states that energy is conserved; that, although it can be altered in form and transferred from one place to another, the total quantity remains constant. Thus, the first law of thermodynamics depends on the concept of energy; but, conversely, energy is an essential thermodynamic function because it allows the first law to be formulated. This coupling is characteristic of the primitive concepts of thermodynamics. The words system and surroundings are similarly coupled. A system is taken to be any object, any quantity of matter, any region, and so on, selected for study and set apart (men...

Analytical Balance

A weighing machine, commercially known as scales, is an appliance for comparison of weighs, for measurement of forces and torque. Its elementary principle is establishing equilibrium between two forces.

Most commonly used elements of scales are, (i) the layer (ii) the pendulum (iii) the spring and (iv) the hydrostatic plunger. Of these (i) and (iii) are frequently used while (ii) and (iv) are used for specific purposes.

Weighing instruments with levers are predominant and their forms are almost unchanges for over a few thousand years. Balance is an example of this type with the beam forming the lever.

The requisites of a good balance are:
  1. Truth: when unloaded or loaded with equal masses on the two knife edges, the beam must be horizontal at rest.
  2. Stability: if the beam is deflected from its position of equilibrium it must return to its original position of rest.
  3. Sensitivity: a small difference between the loads must cause an appreciable deviation of the beam from the position of equilibrium.

A balance is said to be true when (i) the moments of the weights of the arms of the beam about the fulcrum measured from their respective centre of gravity (ii) the scale pans with their attachment are of equal weigh and (iii) the distance between the knife edges and the fulcrum are equal.

The balance is stable when fulcrum is above the center of gravity of the entire beam. When they are coincide, the balance is neutral or conditionally stable, while for the lying above the fulcrum, the beam is unstable and slightest displacement of it from the center gravity horizontal position will overturn it.