What's In You learned earlier how all matter in the universe is made from tiny building
blocks called atoms. All modern scientists accept the concept of the atom, but
when the concept of the atom was first proposed about 2,500 years ago, ancient
philosophers laughed at and opposed the idea. It has always been difficult to
convince people about the existence of things that are too small to be seen. We
will spend some time considering the evidence (observations) that helped
convince scientists of the existence of atoms.
Do you have any idea how the different elements on the periodic table were
formed, known and identified? Let's have a short review.
There is what we call Big Bang Theory that has some key stages: Singularity,
Inflation, Nucleosynthesis and Recombination: Let us differentiate them.
Singularity is a one-dimensional point which contains a huge mass in an
infinitely small space, where density and gravity become infinite and space-time
curves infinitely, and where the laws of physics as we know them cease to
operate. The basic homogeneity in distribution of matter in the universe was
established as a consequence of the first phase of inflacion. Nucleosynthesis
was the nuclear fusion and the formation of new nuclei actions in the early
stages of development of the universe. Recombination - the formation of the
capture of free electrons by the cations in a plasma.​

Mantle convection  is the slow  creepingmotion of earth's solid silicate  mantle  caused by  convection  currents carrying  heat from the interior  to the planet's surface.[1][2]  the earth's surface  lithosphere, which rides atop the  asthenosphere  (the two components of the  upper mantle), is divided into a number of  plates  that are continuously being created and consumed at their opposite  plate boundaries. accretion occurs as mantle is added to the growing edges of a plate, associated with  seafloor spreading. this hot added material cools down by  conduction  and  convection  of heat. at the consumption edges of the plate, the material has thermally contracted to become dense, and it sinks under its own weight in the process of  subduction  usually at an  ocean trench.[3]this subducted material sinks through the earth's interior. some subducted material appears to reach the lower mantle,[4]  while in other regions, this material is impeded from sinking further, possibly due to a phase transition from  spinel  to  silicate perovskiteand  magnesiowustite, an  endothermic reaction.[5]the subducted oceanic crust triggers  volcanism, although the basic mechanisms are varied. volcanism may occur due to processes that add buoyancy to partially melted mantle causing an upward flow due to a decrease in density of the partial melt.secondary forms of convection that may result in surface volcanism are postulated to occur as a consequence of intraplate extension[6]  and  mantle plumes.[7]it is because the mantle can convect that the  tectonic plates  are able to move around the earth's surface.[8]mantle convection seems to have been much more active during the  hadean  period, resulting in gravitational sorting of heavier molten  iron, and  nickel  elements and  sulphides  in the core, and lighter  silicate minerals  in the  mantle.

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