Energy

What is energy

All organisms need energy to live. Energy is connected to all human activities: whenever we think or move, we use the energy that is stored in our body and all the objects that we use or that surround us need energy to work or needed energy when they were built. Energy illuminates us and warms our houses, allows us to move, feeds the tools we use to produce food, and so on. All that produces energy is “an energy source”. The Sun is the main source of energy for the Earth. The Earth receives from the Sun an uninterrupted flow of energy that, as well as supplying all vital processes (both vegetal and animal), melts the ice and supplies the water cycle between the sea and the atmosphere; it produces the wind, favours the growth of those plants that during millions of years have transformed, together with animal remains, into fossil fuels, coal and natural gas. In general, all the energy available on our planet derives, directly or indirectly, from the Sun: water energy, wind energy, chemical energy of fossil fuels (coal, oil and natural gas) and biomass (i.e. wood); even waves energy. Tides energy derives from the gravitational fields of the Sun, Moon and Earth. Geothermal and nuclear energy do not derive from the subsequent transformations of solar energy, but are related to the Earth formation.