Methylphenidate is a commonly prescribed psychostimulant and works by increasing the activity of the central nervous system. It produces such effects as increasing or maintaining alertness, combating fatigue, and improving attention. The short-term benefits and cost effectiveness of methylphenidate are well established.
(image copied from here). 1  Igneous Rocks: form by crystallizing melted material (magma). 2  They can form either on the surface (extrusive igneous rocks), or deep in the crust (intrusive or plutonic igneous rocks).
As these pockets of magma cool slowly they become igneous rocks. Igneous rocks are also formed when volcanoes erupt. Igneous rocks are formed as the lava cools above ground. The upper 16 km of the Earthâs crust is composed of 95% igneous rock.Intrusive igneous rocks are formed from magma that cools and solidifies underground.These rocks are coarse grained.gneous rocks are formed as the lava cools above ground. The upper 16 km of the Earthâs crust is composed of 95% igneous rock. Intrusive igneous rocks are formed from magma that cools and solidifies underground. These rocks are coarse grained.