you need
  • - computer or calculator;
  • - Roulette;
  • - measuring capacity;
  • - line.
As you know, things that are the same volume, but made of different materials have different masses (wood, metal, glass and plastic).Mass bodies made of the same material (without voids), are directly proportional to the volume of treated subjects.In other words, the constant is the ratio of the mass of the object to its volume.This value is called "the density of matter.In the future, it is denoted by the letter d.
Based on the definition, d = m / V, where
m - the mass of the object (kg),
V - its volume (m3).
As can be seen from the formula, the density of matter - is the mass per unit of its volume.
Learn density of the material from which the object is made, it is possible from the table
of densities in the annex to the textbook of physics or website , which shows the density of almostall existing substances.
volume of the object can be calculated by the formula: V = S * h, where
V - volume (m3),
S - area of ​​the base object (m2),
H - the height of the object (m).
If you can not make a measurement with an accuracy of the geometric dimensions of the body, use the law of Archimedes.To do this, take a vessel having a scale (or division) for measuring the volume of liquid in the lower object water (itself vessel equipped divisions).The volume, which will increase the contents of the vessel - is immersed in a volume of the body.
If you know the density d and the volume V of the object, you can always find its mass, using the formula: m = V * d.Before calculating the weights are all the units into a single system, for example, in the international SI system of measurement.
conclusion of the above formula is as follows: to obtain the desired value of the mass, knowing the density and volume, it is necessary to multiply the volume of the body in the density of matter, from which it is made.