3. Energy is a fundamental physical quantity, describing the ability of a material body to perform a specific work. The processes in which one kind of energy turns into another (eg when electric heater heats, charges in the spiral may turn into internal energy of surrounding air and the radiator internal energy) is always associated with some sort of interactions describing these forces work impact is equal to the amount of changed energy.

4. Energy has always been and will be needed for people in their lives. Its use may be different, but above all we need it to produce electricity for transportation, heating homes and illumination.

5. Primary energy sources are:  Conventional sources (organic)  fossil fuels (coal, oil, gas)  nuclear fuel,  geothermal energy,  renewable energy sources.

6. For renewable energy sources are included:  solar energy,  water,  wind,  tidal and wave,  and biomass energy.

7.  Thermal energy is part of the internal energy system, which is associated with the chaotic motion of molecules. A measure of thermal energy is temperature.  Processing of thermal energy into electricity is the subject of termoenergetics. The exchange of energy between systems through the chaotic motion of molecules or atoms is called a heat exchange.

8.  Electricity is the energy of electric charges - and its electrodynamic, if they move, or electrostatic, if they are at rest.  In practice, the electrical energy means electrical energy. It can be converted into energy of electromagnetic radiation (light bulb, LED luminescence, Electric heating device), or mechanical energy (electric motors, speakers).

9.  Mechanical energy is the energy associated with the movement of mechanical system as a whole or its individual parts to each other.  Types of mechanical energy:  kinetic energy - which applies to bodies in motion  potential energy - associated with the interaction.

10.  Potential energy called the energy of body, which remains at rest.  There are two types of potential energy:  gravitational potential energy - for example, the body can be exited at any height  and potential energy of elasticity, such as shot clock.

11. Kinetic energy is energy of a body moving in relation to a reference point. The kinetic energy which is held by the body can be converted into other forms of energy, or it can be transferred to another body (eg by collision with him). The kinetic energy can be consumed to perform some work, for example, set in motion another body, or overcome friction.

12. Internal energy of body is the sum of kinetic energy of all its particles which are in chaotic movement and their potential energy resulting from mutual intermolecular force. Inner energy of the body changes while doing work when you overcome the force of friction such as rubbing hands.

13. Nuclear energy is the energy emitted during nuclear transformations. The liberation of nuclear energy is the fission of heavy atomic nucleus, consisting of protons and neutrons into two nuclei of lighter elements, releasing heat due to weight loss and freeing from 0 to 8 neutrons. Emitted neutrons can hit other nuclei, which undergo fission. As a result, more and more free neutrons come into being and more nuclei of heavy atoms are split, which increases the portion of energy.

14.  Binding energy is the energy needed to separate the system to its component parts.  This term is usually used in nuclear physics and relates to the atomic nucleus. Binding energy of atomic nucleus determines the energy required to separate the nucleus of protons and neutrons. Binding energy is an important criterion in determining the stability of the atomic nucleus.

15. Hydropower energy deals with the acquisition of water energy and its processing into the mechanical and electrical energy using water engines (turbines) and hydrogenerators (eg mills) in hydros, and other devices.

16. Solar energy can be direct source of energy through the use of so-called solar cells. Solar cell is a flat plate consisting of two very thin layers. The sun's rays falling on the cell give rise to electric current which is sent to the electric circuits or batteries. Solar cells are constantly being improved. Maybe in the future they will be deployed on vast areas of desert because of its high heat. In this way, the energy obtained in these areas would be sent to recipients in other countries.