Wegener also noted that the continents move up and down to maintain equilibrium in a process called isostasy. As an example he cited the sinking of Northern Hemisphere lands under the weight of continental ice sheets in the last ice age, and their rise since the ice melted some 10,000 years ago.
Drill bits are cutting tools used to create cylindrical holes, almost always of circular cross-section. Drill bits come in many sizes and have many uses. Bits are usually connected to a mechanism, often simply referred to as a drill, which rotates them and provides torque and axial force to create the hole.
Drill bit (well) In the oil and gas industry, a drill bit is a tool designed to produce a generally cylindrical hole (wellbore) in the earthâs crust by the rotary drilling method for the discovery and extraction of hydrocarbons such as crude oil and natural gas. This type of tool is alternately referred to as a rock bit, or simply a bit.