Where do corks come from?

The corks that seal the wine bottles come from the bark of the cork oak, which grows in Spain, Portugal and North Africa. This elastic bark contains a waxy substance that keeps moisture from passing through the wood.

About half of each cork is composed of empty space. A piece of cork barely one cm³ contains about 200 million cells filled with air. It is those air cells that allow a cork to float and be compressed to fit in a bottle. Once in the neck of the bottle, the cork expands to fill the opening, leaving out the air and moisture.

More than 340 thousand tons of cork are produced each year, with Portugal as the maximum producer. But due to the many bottles of wine that come on the market around the world, there are just enough corks to cover the demand.

The longest flight of a cork shot out of a bottle of champagne is about 31 meters!

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Where does Asphalt Come from?

In paving a street men often use a black, tarlike ma­terial. The material is asphalt. Asphalt is also used in the making of roofing paper, shingles, tiles for flooring, and paints.

Asphalt is found in places where there is or used to be petroleum. It may flow slowly out of the ground and collect in pools. The asphalt that comes from the ground is called natural asphalt. Asphalt can also be made from petroleum.

When asphalt stands, it changes from a thick liquid to a soft solid. Chunks of as­phalt are often found floating on the Dead Sea. In early times much asphalt was mined near this sea. Farther north. in Mesopotamia, the land between the Tigris and Euphrates rivers, there were many as­phalt springs, too. The people in that región long ago cemented bricks together with as­phalt to make pavements. They also sealed jars with asphalt.

The famous tar pits of California are pools of asphalt. In these pools scientists have found many wonderful fossils of mammoths, sabertooths, vultures, and other animals of the great Ice Age. So many fossils have been found in these pools that sometimes they are called "the deathtrap tar pools."

It is not hard to see how the deathtraps worked. After a rain, water covered the asphalt. Animals that waded out to get a drink became caught in the sticky substance and began to sink. Meat eaters—wolves and sabertooths—saw them and sprang on them. Then the meat eaters were caught, too.