How to calculate the specific gravity

Any substance has characteristics. And the main of the characteristics of any substance - weight, or rather - the specific weight, the ratio of the weight of a specific body and the volume occupied by this body. This indicator follows from the mechanical definition of matter. It is through him that we are making a transition to the sphere of qualitative determinations. Matter for us is no longer an amorphous mass, striving for its center of gravity. Well, for example - the solar system - all its bodies are different in terms of specific gravity (how to calculate the specific gravity - a little lower), because they have their own weight and volume. If we take our Earth and its shells (lithosphere, hydrosphere, atmosphere) separately, it turns out that they also have their specific gravity, different and individual.

Similarly, individual chemical elementshave their own weight, only the atomic one. This is also an expression of specific gravity. By the way, there are only a few elements that can be represented in pure form, and all the rest-compounds, as a rule, are stable and bearing the name of simple substances. In the lithosphere of our planet there are more than five hundred, each with its specific gravity. How to calculate the specific gravity? And in general, can this be done?

Of course. Right now, and consider how to calculate the specific weight. It is better to do this on specific examples to make it clearer.

1. For example, you are the head of a woodworking shop and want to know how to calculate the specific weight of selling specific goods or working material in this case. Must be known: the magnitude of the sale of a particular product and the total volume. Suppose we have: a product type - a board, revenue - 15500 (rub), weight specific - 81.6%; product type - timber, revenue - 30000 (rub), specific weight 15.8%; product type - croaker, revenue - 190000 (rub), specific weight 2.6%. Total: revenue - 190,000, and specific weight (total), respectively, 100%. How to calculate the specific weight of the board? We divide 155,000 by 190,000 and multiply by one hundred. We get 81.6%. This is the specific weight of the board.

2. How to calculate the specific gravity of any substance?

Specific weight for some reason is often confused withdensity, although the concepts are completely different. The specific gravity does not refer to the physicochemical characteristics and differs from the density, say, by weight from weight.

2.1.) Density is the ratio of mass to volume, and the specific gravity is the ratio of weight to volume, this formula can be represented as follows: γ = mg / V. And if the density is the mass ratio of a given body to the volume of this body, then we write the formula for finding the specific weight, in this form: γ = ρg.

2.2.) If desired, you can find the specific gravity through volume and mass, or by the experimental method, by comparing the pressure values. Here the hydrostatics equation will be used: P = Po + γh. But this method is applicable only in the case when all the measured quantities are known without exception. In this case, the formula for finding the specific weight will take the following form: γ = P-Po / h. This equation is usually used to describe communicating vessels and their action. On the basis of experimental data, the conclusion will be that each substance in the vessels communicating will have its own height and its own spreading velocity along the walls of the vessel in which this substance is located.

2.3.) In order to calculate (calculate) the specific gravity, we can apply one more formula (Archimedes' force). Do you remember school lessons in physics? Perhaps, only a few will answer in the affirmative. Therefore, we refresh the memory: the force of Archimedes-sila is pushing. Let's say that we have a cargo with a certain mass (we will designate this load as "m"), which is kept on water. At this moment, two forces act on the load, the first is the gravity force, and the second is Archimedes (the force is pushing, and the direction is back to the vector mg). In the formula, Archimedes' strength looks like this: Fapx = ρgV. Knowing that ρg equals the specific fluid weight, we obtain the following equation: Fapx = yV, and from this we derive: y = Fapx / V.

Complicated? Then simplify: in order to calculate the specific gravity, divide the weight by volume.