How to find density?
Density is usually called a physicala value that determines the ratio of the mass of an object, substance or liquid to the volume that it occupies in space. Let's talk about what is density, what is the difference between the density of the body and matter and how (with what formula) to find the density in physics.
Types of density
It should be clarified that the density can be divided into several types.
Depending on the object under study:
- The density of a body - for homogeneous bodies - is the direct ratio of the mass of the body to its volume occupied in space.
- Density of matter is the density of bodies consisting offrom this substance. The density of substances is constant. There are special tables where the density of different substances is indicated. For example, the density of aluminum is 2.7 * 103 kg / m3. Knowing the density of aluminum and body weight, whichfrom it is made, we can calculate the volume of this body. Or, knowing that the body is made of aluminum and knowing the volume of this body, we can easily calculate its mass. How to find these quantities, we will consider later, when we derive a formula for calculating the density.
- If the body consists of several substances, then fordetermination of its density, it is necessary to calculate the density of its details for each substance separately. This density is called the average density of the body.
Depending on the porosity of the substance of which the body consists:
- True density is the density that is calculated without taking into account the voids in the body.
- Specific density - or apparent density - is one that is calculated taking into account the voids of a body consisting of a porous or friable substance.
So, how to find the density?
The formula for calculating the density
The formula that helps to find the density of the body is as follows:
- p = m / V, where p is the density of matter, m is the mass of the body, and V is the volume of the body in space.
If we calculate the density of a gas, the formula will look like this:
- p = M / Vm p is the gas density, M is the molar mass of the gas, Vm - molar volume, which under normal conditions is 22.4 liters / mol.
Example: the mass of the substance is 15 kg, it takes 5 liters. What is the density of matter?
Solution: substitute values in the formula
- p = 15/5 = 3 (kg / l)
Answer: the density of the substance is 3 kg / l
Units of density measurement
In addition to knowledge of how to find the density of the body and matter, you need to know and units of density.
- For solids - kg / m3, g / cm3
- For liquids - 1 gr / l or 103 kg / m3
- For gases - 1 gr / l or 103 kg / m3
More information about the density units can be found in our article. What is the density?
How to find the density in the home
In order to find the density of the body or substance at home, you will need:
- Libra;
- A centimeter if the body is solid;
- A vessel, if you want to measure the density of a liquid.
To find the density of the body at home,You need to measure its volume with a centimeter or a vessel, and then put the body on a scale. If you measure the density of the liquid, then do not forget to subtract before weighing the mass of the vessel into which you poured the liquid. The density of gases at home is much more difficult to calculate, we recommend using ready-made tables, in which the densities of various gases are already indicated.
