What Is Clay?
Clay is a special kind of earth. It is made up of the smallest particles of rock, tinier than those in most other kinds of soil. The minerals that make up ordinary clay...
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When Was the Pencil Invented?
When Was the Pencil Invented? Did you know that modern pencils owe it all to an ancient Roman writing instrument called a stylus? Scribes used this thin metal rod to...
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What Is Cement Made From?
What Is Cement Made From? Cement is made from a mixture of lime, clay, silica, iron and aluminum minerals. Limestone is the most important source for the calcium, while...
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How Are Bricks Made?
The ordinary bricks a bricklayer uses to construct a brick building are made from clay that is baked in an oven. The clay is mixed with sand and water. This “mud” is...
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What Is Pencil Lead Made of?
The common name “pencil lead” is due to an historic association with the stylus made of lead in ancient Roman times. The ancient Romans used a writing device called a...
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