Energy and kids

Energy history

Energy has a long history. Beginning back before people could read and write, fire was discovered to be good for cooking, heating and scaring wild animals away. Fire was civilization's first great energy invention, and wood was the main fuel for a long time.

Energy is essential to life. Living creatures draw on energy flowing through the environment and convert it to forms they can use. The most fundamental energy flow for living creatures is the energy of sunlight, and the most important conversion is the act of biological primary production, in which plants and sea-dwelling phytoplankton convert sunlight into biomass by photosynthesis. The Earth's web of life, including human beings, rests on this foundation.

Over millennia, humans have found ways to extend and expand their energy harvest, first by harnessing draft animals and later by inventing machines to tap the power of wind and water. Industrialization, the watershed social and economic development of the modern world, was enabled by the widespread and intensive use of fossil fuels. This development freed human society from the limitations of natural energy flows by unlocking the Earth's vast stores of coal, oil, and natural gas. Tapping these ancient, concentrated deposits of solar energy enormously multiplied the rate at which energy could be poured into the human economy.

The result was one of the most profound social transformations in history. The new river of energy wrought astonishing changes and did so with unprecedented speed. The energy transformations experienced by traditional societies--from human labor alone to animal muscle power and later windmills and watermills--were very slow, and their consequences were equally slow to take effect. In contrast, industrialization and its associated socioeconomic changes took place in the space of a few generations.

Prehistoric Era
Horse Animated Before the Industrial Revolution of the 1890s, human beings had only a moderate need for energy. Man mostly relied on the energy from brute animal strength to do work.

Man first learn to control fire around 1 million BC. Man has used fire to cook food and to warm his shelters ever since. Fire also served as protection against animals.

Thousands of years ago, human beings also learned how to use wind as an energy source. Wind is produced by an uneven heating by the sun on the surface of the earth because of the different specific heats of land and water. Hot air has lower pressure than cold air and since high pressure tries to equalize with low pressure the current called wind is produced. Around 1200 BC, in Polynesia, people learned to use this wind energy as a propulsive force for their boats by using a sail.

About 5 thousand years ago, magnetic energy was discovered in China. Magnetic force pulled iron objects and it also provided useful information to navigators since it always pointed North because of the Earth's magnetic field.

Electric energy was discovered by a Greek philosopher named Thales, about 2500 years ago. Thales found that, when rubbing fur against a piece of amber, a static force that would attract dust and other particles to the amber was produced which now we know as the "electrostatic force".

Around 1000 BC, the Chinese found coal and started using it as a fuel. It burned slower and longer than wood and gave off more heat. It served as an excellent fuel and continued to be used for centuries thereafter. When Marco Polo returned to Italy after an exploration to China in 1275, he introduce coal to the Western world.

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