Tar facts for kids
Tar is a sticky, black liquid that looks like thick oil. It can be found naturally, oozing out of the ground in places like the La Brea Tar Pits. Most often, tar is made by heating materials like coal in a special process.
Tar is usually made from coal when producing a fuel called coke. But it can also come from petroleum, peat, or wood. A process called "destructive distillation" of coal can create tar. For example, one ton of coal can produce about 50 litres of tar. In the past, tar was also a product of places called gasworks. Tar made from coal or petroleum can contain substances that are not good for you. However, in very small amounts, tar is sometimes used as a medicine for skin conditions.
Tar kilns are special ovens used to make tar from wood. They are a type of "dry distillation" oven. These kilns were common in Scandinavia and were built near forests. They could be made from limestone or even simple holes in the ground. The bottom of the kiln was sloped with a hole for the tar to flow out. Wood was cut into small pieces and packed tightly inside. Then, the wood was covered with dirt and moss to keep air out. A fire was lit on top. After a few hours, tar would start to drip out and continue for several days.
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What is Tar Used For?
Tar has many different uses. It is used to treat skin problems like psoriasis, especially coal tar. Tar also works as a general cleaner to kill germs. Long ago, around 1000 BC, tar from petroleum was used in ancient Egypt for mummification.
Tar in Roads and Buildings
Tar was a very important part of the first paved roads, known as "tarmac" roads. The city of Baghdad had some of the first streets paved with tar in the 8th century AD. Tar was also used to seal roofs made of shingles. It helped make the hulls of ships and boats waterproof. For thousands of years, wood tar was used to waterproof sails and boats. Today, sails are often made from materials that are already waterproof. However, wood tar is still used to seal traditional wooden boats. It also protects the roofs of old shingle-roofed churches and the outside walls of log buildings.
Tar Paint
You can make tar paint by mixing tar with linseed oil varnish. This paint helps protect wood from bad weather. Tar paint can also be colored with different pigments. This creates see-through colors that still show the wood's natural texture.
Related pages
Images for kids
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Tar kiln at Trollskogen in Öland, Sweden.
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Birch tar.
See also
In Spanish: Brea para niños
