voa.慢速英语 Wor第一篇d 文档

By Dana Demange

2011-10-4

STEVE EMBER: I'm Steve Ember.

BARBARA KLEIN: And I'm Barbara Klein with EXPLORATIONS in VOA Special English. At the Smithsonian American Art Museum in Washington, D.C. you might see two cowboy boots. They are painted with a design of clouds and stars.

They look like boots that you could wear on your feet. But they are really made out of carefully formed clay material. The artist William Wilhelmi made these ceramic pieces. How did he make these colorful boots? Today, we answer that question as we explore the world of clay art.

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Smithsonian American Art Museum

William Wilhelmi made "Cowboy Boots" in 1980.

STEVE EMBER: Clay is one of the most universal materials known to humans. Throughout history and around the world, people have developed the art of forming clay to make ceramic objects, or pottery. Clay is m ade of water and earth. It is formed into different shapes. The n high levels of heat harden it to produce many kinds of ceramics.

Different kinds of clay contain different minerals such as silicon or iron dioxide. The kinds of minerals in clay affect how soft or hard it is to work with. The mineral content of clay also affects the temperature level at which it hardens.

BARBARA KLEIN: Earthenware is one of the earliest kinds of clay used by humans. Earthenware hardens at a lower temperature than another clay called stoneware. Porcelain is yet another kind of clay.

It is very fine and smooth. All these clays need to be fired at high temperatures. Early pottery was heated in the sun or by a fire. Later, potters developed heated devices called kilns to control the necessary firing conditions.

STEVE EMBER: The development of ceramics has had an important effect on human history. Ceramic objects permitted early cultures to make containers that could hold water. This means they could cook foods like vegetables and meats. Improving food production methods meant larger populations could survive. Pottery is an art form that grew out of the daily needs of life.

Ceramics are also important for historians and archeologists. Pieces of ceramics found at archeological areas help tell about ancient cultures. These pieces can last for tens of thousands of years. They help answer questions about cultures we know little about.

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BARBARA KLEIN: There are many different ways to form clay. The earliest methods involved shaping it by hand. People form containers by pressing a ball of clay into a given shape.

Or, they place long thin rolls of clay on top of each other and then make them smooth. Another method is called slab-construction. A ceramist creates several flat pieces of clay that can be joined together to make the sides of the container.

Later, ceramists developed the method of "throwing" clay on a wheel. A ball of clay is placed on a flat wheel device that turns quickly. The potter holds the clay firmly and guides it while the wheel and clay turn. Using different am ounts of upward pressure the potter can build up the sides of a container. This method permits a potter to make similar pieces quickly. But it takes a great deal of skill to become an expert at wheel throwing.