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.

Tektite

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Tektite, any of a class of small, usually dark colored glassy objects found scattered in an S-shaped belt over a large area of the earth's surface. The belt stretches from Australia, through southeastern Asia, eastern Europe, the western coast of Africa, and South America, to Georgia and Texas. Despite their chemical similarity to some igneous and sedimentary rocks found on the earth, tektites do not belong to the rock groups in which they occur. This fact has given rise to various theories about their origin, based mainly on their shape and distribution.

The glassy composition and irregular shapes of tektites strongly suggest an extraterrestrial origin; the molten rounded shapes were probably acquired in flight through the atmosphere at very high speed. The theories proposed include: (1) the tektites represent lunar material thrown off the moon's surface following meteorite collisions; (2) they were formed by a meteorite crashing onto the earth, forcing a great deal of debris into the atmosphere; (3) they are the fragments of an exploding planet or meteorite passing through the atmosphere of the earth.