Balance
The calibration of a spring balance depends on the force of gravity that acts on the object, by that they must be calibrated in the use place. ew York City. They are used if is not required high accuracy. 2. Balance of sliding weight. It has two well-known masses that they are possible to be moved on scales one with a graduation macro and the other with a micro graduation ; when placing a substance of mass unknown on the tray, determines its weight sliding the masses on the mentioned scales until the balance position is obtained. At this moment one takes the reading adding the amounts indicated by the position from the masses on the mentioned scales. 3. Analytical balance.
It works by means of the comparison of masses of weight known with the mass of a substance of unknown weight. A bar or symmetrical handle is constructed with base in that leans by means of a support type blade in a central point denominated fulcrum. In their ends stirrups or sockets exist that also are supported by means of blades that allow them to oscillate smoothly. they are suspended two subjects of gossip there. In one the certified masses or weights and in the other those are placed that it is necessary to analyze. All the set has a system of securing or blockade that allows the main handle to rest of stable form when it is not used or when they are required to modify the counterbalances. It has an external box that it protects the balance of the interferences, like airflows, that could appear in the place where it is installed. At present, it is considered that an analytical balance is that one that can weigh ten thousandth of gram (0.0001 g) or one hundred thousandth of gram (0.00001 g); they have a capacity that reaches generally to the 200 grams.