fluence occurs and the pencil has diverged aside. The springs would immediately seek to return a pencil to the former position, i.e. the system starts to operate. Where does it take energy for the actions from? This energy was brought by the external influence in the form of kinetic energy of pushing by a finger which has compressed (stretched) the springs and they have reserved this energy in the form of potential energy of compression (stretching). As soon as external influence (pushing by a finger) has ceased, potential energy of the compressed springs turns to kinetic energy of straightening thereof and it returns a pencil back in the vertical balanced position. External influence enhances internal energy of the system which is used for the performance of the system. The influence causes surplus of internal energy of the system which results in the reciprocal action of the system. In the absence of influence no surplus of the system's internal energy is available which results in the absence of action. External influence brings in the energy in the system which is used to produce reaction to this influence. Functions of springs may be performed by airflows created by fans located on a pencil. In order to "build" airflows surplus of energy of the "fans - pencil" system is used which is also brought in from the outside, but stored for use at the right time (for example, gasoline in the tank or electricity in accumulator). Such system would be active because it will use its internal energy, rather than that of external influence. The difference between airflows and springs consists in that the airflows consist of incidental groups of molecules of air (not systems) moving in one direction. Amongst these elements there are executive elements (SFU, air molecules), but there is no control block which could construct a springs-type system out of them, i.e. provide the existence of airflows as stable, separate and independent bodies (systems). These airflows are continually created by fan propellers and as they have no control block of their own they always collapse by themselves. Suppose that we construct some kind of a system which will ensure prevention of the airflows from collapse, let's say, encase them in rubber cylinders, they then may exist independently of fans. But in this case the system of stabilization of the pencil's vertical position will shift from the active category to the passive. Hence, both active and passive systems consume energy. However, the passive ones consume the external energy brought in by external influence, while the active ones would use their own internal energy. One may argue that internal energy, say, of myocyte is still the external energy brought in to a cell from the outside, eg in the form of glucose. It is true, and moreover, any object contains internal energy which at some stage was external. And we probably may even know the source of this energy, which is the energy of th...
