In the nature there are 4 types of interaction: gravitational, electromagnetic, weak and strong. Strong interaction carries out strong communication of components of a nucleon in an atomic nucleus.
Nucleons and quarks
Nucleons call tiny particles of which the atomic nucleus consists. Carry protons and neutrons to them. A proton - the hydrogen atomic nucleus possessing a positive charge. The neutron has a zero charge. The mass of these two particles are approximately identical (differ for 0.14%). In general atom electrically is neutral. It is provided with a negative charge of the electrons rotating around a kernel. Nucleons participate in strong interaction.
Until recently scientists believed that nucleons are indivisible particles. However this theory failed after opening of kvarkovy model of a kernel and carrying out the experiments confirming its validity. According to it, protons and neutrons consist of smaller particles - quarks.
Each nucleon consists of three quarks. They have specific characteristic - "colour" (has no relation to color in traditional understanding). By this word it is accepted to designate their charge. Quarks carry out strong interaction, exchanging among themselves special quanta - gluons (it is translated as "glue"). Communication between protons and neutrons in a kernel is formed by means of the residual strong interaction called nuclear. It is not among fundamental.
Strong interaction
It is one of four fundamental interactions in the nature. It is carried out only at distances of an order of a femtometr. Strong interaction is one thousand times more powerful than electromagnetic. He sometimes for fun is called the knight with short hands. Quarks do not meet in a free state and are so strongly connected among themselves that they cannot be divided. At least modern science does not know as it can be carried out. The phenomenon of strong interaction is that at increase in distance between quarks, force of interaction between them increases several times. On the contrary, at rapprochement interaction force considerably weakens. Unlike strong, force of nuclear interaction sharply decreases with increase in distance between nucleons. The quantum chromodynamics is engaged in studying kvarkovy interaction. It studies properties of the glyuonny field and also characteristic of quarks (strangeness, a charm, color and others). In standard model only quarks and gluons are capable to carry out strong interaction. In the gravitational theory it is allowed also for leptons.