So we expect that the description of the velocities of molecules in a gas will in fact be the most probable distribution, since we are dealing with particle numbers in the range of Avogadro's number. But this most probable distribution (the Maxwell-Boltzmann distribution) is subject to constraints, namely that the number of particles is constant and that the total energy is constant (conservation of energy).
The oldest rocks are metamorphic gneisses which are to be found on Inishtrahull, several miles off Malin Head in Co. Donegal, and elsewhere in the north-west. They originally formed as igneous rocks 1750-1780 million years ago.
Igneous rocks are formed when melted rock cools and solidifies. Melted rock may come in the form of magma, when it is found underneath the Earthâs surface. It can also come in the form of lava, when it is released unto the Earthâs surface during a volcanic eruption.Some examples of igneous rocks are granite, scoria, pumice, and obsidian.Pumice, for instance, is formed when lava made up of melted rock, water, and trapped gas is ejected from a volcano during a violent eruption.ome examples of igneous rocks are granite, scoria, pumice, and obsidian. Pumice, for instance, is formed when lava made up of melted rock, water, and trapped gas is ejected from a volcano during a violent eruption.