WHAT IS ENERGY?
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WHAT IS ENERGY?
The origins of energy. Energy through the ages. Definition of energy. Physical and chemical changes. The discovery of fire: calorific energy. The invention of machines. Actual energy source: petroleum. Transformation of energy: windmills, photosynthesis, mechanical, electrical and luminous energies. The Sun, Earth’s principal source of energy. Sources of energy. Energy reserves. Summary.
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INTRODUCTION
- All bodies constantly modify their features. Each one of those changes needs energy.
- Heat, light, electricity, movement, sound and nuclear forces are all different aspects of the same thing: energy!
- Man has understood the true importance of energy in Nature.
- Man uses energy in all his activities.
ENERGY
- Definition of energy
- Physical and chemical changes
- Nuclear changes
- The tools. Energy and the animals. Fire, wood, coal and fuel.
TRANSFORMATION OF ENERGY
- Man has managed to transfor different sources of energy into others. The water-mill.
- Plants use the Sun’s energy in photosynthesis.
- Energy might appear in different forms, but it is always energy. Different kinds of energy are distinguished by the type of change which takes place in which they intervene: mechanical energy, calorific energy, electrical energy, luminary energy, etc.
- In order to create a certain type of energy, it’s necessary to transform an earlier, available kind.
- The biggest source of energy which we count upon on this planet is the Sun.
- Kinetic energy
ENERGY SOURCES
- The Earth receives only half of one 10 millionth part of the energy radiated by the Sun. But in just a few days, receives as much light and heat as it would be produced by our consuming all available petrol, coal and wood on the entire planet.
- Evaporation and rainfall
- Photosysthesis
- Crude-oil
- Sea tides
- Our planet has an enormous amount of energy available through natural radioactivity and the Earth’s rotation. We can also depend on its internal heat.
- Nuclear energy
SUMMARY |
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