Wheel that Turns

João Manuel Ribeiro; Illustration: Miriam Reis

«Energy is a complex concept due to the lack of a single object or phenomenon that represents it. The understanding of this concept by each child should go through the construction of their own mental representation, through the recognition of the fundamental properties of energy and its manifestations.

Life is a continuous manifestation of energy exchanges that occur in all our actions. We use energy for everything. The brain, heart, lungs and cells of our body are working continuously, using energy. Since energy is not created, it is necessary to obtain this energy and transform it (in our body). Food provides us with that energy. Animals, like humans, have no ability to use energy from sources other than food. Only plants (and some bacteria) have the ability to get energy directly from the sun (through photosynthesis).

Throughout our existence we have learned to transform the energy existing in the universe. First it was the fire we used to warm ourselves, light us up, and cook ourselves. Then we created machines that worked with the steam produced by heating water (by fire). Later, we replaced wood with other fuels and improved the quality of engines (trains and machines) that started to use the gases produced by combustion to produce movement (instead of the water vapor used by the first machines). Then came electricity, produced by thermoelectric plants (burning fuels), by dams (whose water movement drives turbines) and by other more sophisticated forms, some more environmentally friendly (movement of wind turbines, by the wind) and others more dangerous (nuclear power plants, from transformations involving the nucleus of atoms).»

(Fátima Bento, Cenas & Ciências, University of Minho).

Age: +6