Matter & Energy


Matter is composed of atoms or groups of atoms called molecules. The arrangement of particles in a material depends on the physical state of the substance. In a solid, particles form a compact structure that resists flow. Particles in a liquid have more energy than those in a solid. They can flow past one another, but they remain close. Particles in a gas have the most energy. They move rapidly and are separated from one another by relatively large distances.

Wind Energy

Wind Energy, energy contained in the force of the winds blowing across the earth’s surface. When harnessed, wind energy can be converted into mechanical energy for performing work such as pumping water, grinding grain, and milling lumber. By connecting a spinning rotor (an assembly of blades attached to a hub) to an electric generator, modern wind turbines convert wind energy, which turns the rotor, into electrical energy.

Wind is created when air that has been warmed over sun-heated land rises, leaving a vacuum in the space it once occupied. Cooler surrounding air then rushes in to fill the vacuum. This movement of rushing air is what we know as wind.

Egyptians may have been the first to capture wind energy when they sailed boats up the Nile River beginning around the 4th century bc. For centuries afterward, wind-powered sailing vessels plied the world's seas and oceans, serving as the principal form of commercial transport. Wind energy has been harnessed on land since the first windmill was developed by the ancient Persians in the 7th century ad. Windmills have since been used to mill grain, pump water, saw timber, and provide other forms of mechanical energy.

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