The movement of the body thrown at an angle to the horizon is described in two coordinates. One characterizes flying range, another – height. Time of flight depends on the maximum height which is reached by a body.

The world of science dazzles with terms which sometimes begin to use also in everyday life. However using any given word, people not always correctly understand its value. So it happened also to the concept "verification".

The allotropy is an ability of chemical elements to be in a type of two and more simple substances. It is connected with various number of atoms in a molecule or with the structure of a crystal lattice.

Carrying power of the aircraft which is lighter than air, is defined by its volume and also density of the gas filling it. The last, in turn, depend on its structure and temperature. Some balloons fill with hot air, and others - light gases. Also it is necessary to consider the mass of the cylinder.