Description: This is
a VOA Special English Technology Report.
See text below
Text:
Clay is found almost everywhere in the world. It is
formed by the action of wind and water on rocks over
thousands of years. The rocks change in both
chemical and physical ways. Chemically, elements
like potassium and aluminum are added and taken
away. Physically, the rocks break down into smaller
and smaller pieces. After a long time, some of the
rock changes to clay.
Clay is important because it is used around the
world to make containers of all kinds. Potters add
water to soften the clay. This makes it easier to
form into shapes by hand or by machine. Then it is
fired in an extremely hot stove. The result is a
container with a hard surface that will last for
many years.
In many countries, clay was formed from volcanoes.
This kind of clay usually contains many minerals. So
the fires to make containers from volcanic clay must
be hotter than those used for non-volcanic clay. The
fires may be as hot as one thousand four hundred
degrees Celsius.
It is also important to dry the clay containers
slowly. This means that the highest temperature
should not be reached too fast. You can add
materials to clay to gain desired results. For
example, you can add sand to prevent tiny breaks or
lines from forming in the finished product. But you
should not use sand from the coasts of oceans.
Instead, you should use sand from rivers or from
other areas of land that are not near the sea.
You can usually find good clay in low areas of
islands or land, especially if volcanoes helped form
the land. Clay often exists in fields covered with
some water. The clay will be found about one meter
below the ground. River banks also have clay about
one meter or less under the surface.
You can recognize clay because it is very shiny when
it is wet. You can also perform a test. Take some of
the material and add enough water to it to make it
seem like you are making bread. Then press it in
your hand until it is about the size of an egg. It
is probably clay if it holds together instead of
falling apart when you stop pressing.
And that's the VOA Special English Development
Report. Guides to working with clay and other
materials can be found on the EnterpriseWorks/VITA
list of publications. These publications can be
ordered for a charge. The list is available at
enterpriseworks.org. Transcripts, MP3 and archives
of our reports are at voaspecialenglish.com.
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Hi. I
personally reviewed this video and found it appropriate for
the news section of English Global Group. This
is a Voice of America video which covers an interesting
topic in Special English. I would appreciate some feedback from both
students and teachers about this video. You can comment in
the window below using any of a number of different services
including Facebook, Yahoo, AOL, and Hotmail.
