Physics is an incredibly fascinating science, once you figure out what's what. And the formulas in it reflect real physical processes, only in numbers. And if you understand why the formula is the way it is, then it will be much easier to learn. But it’s impossible to tell everything at once, and today we’ll figure out how to find mass through density and volume.
Before you begin to study the formulas for mass, density and volume, you should clarify some details:
- Firstly, the volume of a substance depends on temperature . When heated, a solid expands, and at low temperatures it contracts. There are also special issues, as in the case of liquid hydrogen. It cannot exist at high temperatures because it will turn into gas.
- Secondly, different organizations and countries have their own standards for the conditions under which measurements are taken . In other words, the numerical density of the same substance will differ in different countries. Therefore, before asserting that the indicators are incorrect or correct, it is necessary to clarify the conditions under which these indicators were obtained.
- Thirdly, in addition to temperature, the volume factor can also be influenced by indicators such as atmospheric pressure . It is especially important when measuring the density of gases, since it has practically no effect on solids.
The formula and the amazing history of its origin
The most common formula for most cases is: m = pV, where m is the mass of the body, p and V are the density of the substance and its volume occupied in space, respectively. You can, of course, not bother and calculate everything on online resources, but knowing the formula is still useful. Accordingly, V = m/p, p = m/V.
The most interesting thing is that the formula was found by a man who ran naked down the street and was at the same time a friend of the king. Interesting? Then the next three paragraphs are for you.
There was such a tyrant king in Ancient Greece as Hiero II. He began to suspect that his crown was not made of pure gold and that the jewelers had cheated him. But Hiero did not know how to prove this. Then he turned to the smartest man of that time - Archimedes. Having received an order to deal with matters of national importance, Archimedes day after day began to look for a solution to the issue.
Oh, and the scientist had a difficult task. After all, at that time there were neither the necessary formulas , nor modern devices, nor Google to quickly find a solution. And then one day, having come to the bathhouse and immersed himself in it, Archimedes noticed that the pouring water was equal in volume to what was immersed in the water.
Eureka! – Archimedes shouted and hurried naked to his laboratory to conduct experiments. The scientist put all the data in his head and later did the following experiment: he took the crown and lowered it into the water. Then he took a piece of gold of the same weight and lowered it into the water. The volume of displaced water turned out to be different. If the crown were made of pure gold, then its volume and the volume of the ingot would match. This proved that the jewelers had deceived the king. Who would have thought that one of the greatest discoveries came about thanks to deceivers, a tyrant and a scientist.
