What Caused the Tower of Pisa to Lean?
What Caused the Tower of Pisa to Lean? The famous Leaning Tower of Pisa in Italy is the campanile (bell tower) of the cathedral in Pisa. The tower tips so far to one...
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What Metals Are Quarters and Dimes Made Of?
What Metals Are Quarters and Dimes Made Of? U.S. quarters and dimes are made of three layers of metal bonded together. The core is copper, and the outer layers are a...
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What Gives Opals Their Colors?
What Gives Opals Their Colors? The beautiful flashes of color given off by a precious opal as it is turned and viewed from different angles are caused by the various...
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Where Does Natural Gas Come From?
Natural gas is believed to be formed from the remains of ancient plants that lived in the shallow seas that once covered much of the earth. Many layers of the decayed...
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What Is Soil?
Soil is a mixture of very small pieces of rock and rotted materials from plants and animals. This rotting plant and animal material, called humus, gives soil its dark...
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