Something about building materials

Thursday, June 16, 2011

In some parts of the world there are few materials to build with. Snow, driftwood, walrus skin, and sod, for instance, are about all an Eskimo can find for building. But in the United States and many other countries, too, there are numerous materi­als to choose from. We can choose from more than a dozen materials for the outside walls. Many other materials can be used for roofs and floors and inside walls, for pipes and gutters and built-in furniture.

Stone is a natural building material. It has only to be cut into the shape wanted. There are dozens of kinds of stone. Those used most in building are limestone, marble, granite, sandstone, and slate. Sometimes the stone is not even cut into shape. Rounded stones called field stones make attractive walls.

Wood is another natural building mate­rial. There are many kinds of wood to choose from. Fine and oak are common.

Snow, grass, palm leaves, and mud are natural building materials, too. No one had to invent them.
But many of our building materials are manmade. They had to be invented. Brick, steel, glass, concrete, plywood, fiber board, and plaster are a few of them.

Some of the materials used in our buildings do not show after the buildings are finished. In many walls, for instance, rock wool is used to shut heat in during the winter and keep heat out during the summer. It does not show. In the same way, no one would guess to look at the great Empire State Building in New York City that a framework made of 57,000 tons of steel is hidden in its walls.

What is a depressant?

A depressant is a drug that reduces the activity of various body functions. Some depressants such as anesthetics, sedatives, antiepileptics, narcotics analgesics, and some muscle relaxants, slow nervous and muscular activity by acting on the central nervous system. Tranquilizers are depressants that affect only part of the nervous system. They induce relaxation without causing total depression.

Facts about birthstones

Facts about birthstones
Did you know? The current assignation of stones to months was established in 1912