Energy Types, Heat Transfer and Electrical Charge

Electrical Charge and Magnetic Field

Electrical charge is a property of matter related to the proportion of protons and electrons in its atoms. Positive electrical charge: this is produced when atoms lose some of their electrons. Negative electrical charge: this is produced when atoms gain some of their electrons. A magnet forms around itself a magnetic field, which is the area in space where its force can be felt.

Energy: Definitions and Internal Energy

Energy is the capacity bodies have to produce changes in themselves and other bodies. Electrical energy is produced by the movement of charges in and through a conductor. Electromagnetic energy is transported by electrical and magnetic waves. Chemical energy is produced during chemical processes. Nuclear energy is stored in an atom's nucleus. Nuclear fission energy: is created by the reactions which are reproduced in a controlled way in nuclear power stations. Nuclear fusion energy: is created by the reactions which take place in the stars. The internal energy of a body is the sum of all the kinetic and potential energies of the particles which form it. Thermal energy: we only take into account the kinetic energy of these particles and not the potential energy. An energy resource allows us to produce energy directly or through some transformation. Renewable energy sources: these are easily regenerated and are inexhaustible. Non-renewable energy sources: these are consumed at a faster rate than they are generated in nature.

Renewable and Non-Renewable Energy Sources

Hydraulic energy comes from the potential energy of water stored at a height. Wind energy is the energy produced by wind and is clean. Solar energy comes to the Earth in the form of radiation from the Sun. It is clean, inexhaustible, free and high-quality energy. Geothermal energy originates from inside the Earth in the form of heat. It is only used in places where there are thermal reserves. Biomass combustion can be used in the form of thermal or electrical energy. Tidal energy uses the movement of the waves and tides to produce electrical energy by moving generators.

Heat, Temperature, and Thermal Equilibrium

Heat is the transfer of thermal energy from one body to another when both bodies have different temperatures. Temperature is a magnitude which measures the degree of movement of the particles. Thermal equilibrium is the state which is reached when the temperatures of two bodies, which were initially different, become the same.

Modes of Heat Transfer

Conduction: is the way in which heat propagates between two points of a body, generally solid, which are different temperatures, without a movement of matter. Convection: is the way in which heat is propagated in fluids (liquids and gases). Heat is propagated in the form of currents. Convection currents: are produced until the temperature is the same throughout the liquid. Radiation: is the only form of energy transmission which is produced from the surface of bodies through a vacuum or material medium in the form of electromagnetic waves.