Pitch (resin)

Pitch is a type of polymer. It can be natural or man-made. It can be gotten from petroleum, coal tar, or plants. Pitch made from plants is also called resin. Some things that are made from plant resin are also known as rosin.
Properties.
Pitch is very viscous. It has a viscosity approximately 230 billion times that of water. An experiment was done by the University of Queensland. The experiment is called the pitch drop experiment. In the experiment, pitch was put in a glass funnel and allowed to slowly drip out. Since the pitch was allowed to start dripping in 1930, only nine drops have fallen. The eighth drop fell on 28 November 2000, and the ninth drop fell on 17 April 2014.
Uses.
Pitch was used to help caulk the seams of wooden sailing vessels. It was used to cover earthenware containers to preserve wine. Pitch may also be used to make wooden containers waterproof. It is also used in making torches that use fire.
It is used for polishing high-quality optical lenses and mirrors. Some types of pitch is used in making jewellery.