tar

📅 Updated:2018-09-03

🕒 Created:2018-09-03

🆔 ID:21103

Description

Tar is a thick, flammable substance used in waterproofing. It can be produced from pine trees by heating (but not burning) them in a kiln, from fermented sap in swamps, or from petroleum oil. Petroleum tar occurs naturally in certain areas, creating tar pits, which are a sinking hazard.