assumption that in nature everything is made of tiny particles, expressed even by the ancient Greek philosophers.This hypothesis has long remained unproven.All study of the world and the behavior of physical bodies based on a macroscopic approach.However, over time, the accumulated results of studies on the nature and substance no longer fit into the existing theoretical concepts, and then the scientists had created molecular-kinetic theory (ICB).
MKT explain thermal phenomena and the intrinsic properties of physical bodies on the basis of the movement and interaction of ions, molecules, and atoms of which are constructed and these bodies.In other words, the theory tries to explain macroscopic phenomena from the standpoint of the microscopic approach.The main provisions of the molecular-kinetic theory of the following:
- substance consists of individual particles - ions, atoms, molecules.
- all the particles move randomly and continuously.
- particles are always at each other, attract and repel.
first postulate, which is based on molecular-kinetic theory can be confirmed by simple observation in the electron microscope.Its features allow you to directly see atoms and molecules.These "building blocks", which consists of a substance do not fill all the available space - they are spaced from each other.Another confirmation of the postulate may be an increase in body size during heating.Here, too, it is clear - by heating the distance between individual particles is increased and the size of the body increases.
In the second position, the ILC states chaotic and continuous movement.This position can be confirmed by the phenomenon of Brownian motion and diffusion.The reason is Brownian motion collisions between individual particles, and it is moving chaotically.And it can be regarded as further evidence of the first position (the existence of atoms and molecules).
phenomenon of diffusion is in the mutual penetration of substances into each other.This happens because of the chaotic motion of particles of matter.By increasing the interaction time of the penetration depth increases.It also depends on temperature and pressure.
As evidence of the third position can be taken MKT elastic bodies.When stretched, the body of the distance between the individual particles of matter increase and begin to dominate the forces of gravity, tend to return everything to its original position.During compression, on the contrary, is dominated by the repulsive force.
Well argument confirming this are the various states in which the substance may be.The change of state of matter due to the change of the forces acting between individual particles.While the particles thus remain unchanged.
If we return to the question of occurrence of the ILC, we can say that the basis of the molecular-kinetic theory were laid in the works of MV Lomonosov.They were given an explanation of the basic properties of natural gas and heat.His assumptions were proved and confirmed at the end of the tenth century, I X.
Works theoretical physicists at the time has been set for the gas connection of macroscopic parameters (temperature, pressure, volume) with microscopic (number, mass and velocity of the molecules).Hence the name - the molecular-kinetic theory.It should be noted that the development of this theory did not stop, continuing to this day.Now it is called statistical mechanics, and describes the behavior of large amounts of atoms and molecules.
above given explanation of what the molecular-kinetic theory.The basic position and it sets out the facts confirm the hypothesis.