Berzelius tried to bridge this gap in 1809 by formulating the Vital Force Theory which stated that organic compounds can never be synthesised starting with inorganic components, i.e. a vital force was required for the synthesis of organic compounds which is absent in other molecules.
After nearly two decades, the death blow came of the vital force theory came. Friedrich Wohler in 1828 synthesised urea from inorganic potassium cyanate and ammonium nitrate.
4. LUMINIFEROUS ETHER
This theory was established in the 19th century by scientists (Robert Boyle was prominent among them) due to the firm belief that waves can transmit only through material medium. The argument could not explain the transmission of light waves from Sun to Earth which are separated by emptiness (vacuum). So they devised the existence of the medium ether which occupied all volume devoid of other media.
The ether theory withered away with the advancements of electromagnetic wave theory; which proved the possibility of transmission of EM waves even in vacuum. This removed the significance of Ether’s existence and since no proofs supporting its existence were ever found, it was game over for Ether.
3. PHLOGISTON THEORY
Phlogiston theory was introduced by Johann Joachim Becher in 1667. It stated the existence of phlogiston, a tasteless, odourless, mass less entity contained in matter that enables its combustion. Though seemingly foolish now, the theory held firm for nearly a century, until it was disproved by Mikhail Lomonosov.
The theory states that phlogisticated substance burns in air to become dephlogisticated to yield residue calx and this in turn makes the air phlogisticated. This model is opposite to the role of oxygen in the modern oxidation theory. The fact that burning of a substance in a closed container ceases after sometime is explained in the Phlogiston theory by proposing that the air in the container gets saturated with phlogiston by that time.
Lomonosov disproved the theory by providing some experimental and theoretical proofs, among which the simplest is the fact that burned metals gains in weight which contradicts the removal of phlogistons from the metal. The Phlogiston’s defence to this by assuming negative mass was short lived.
In many ancient civilisations it was believed that the Earth was the centre of the universe and the Sun, Moon and other celestial bodies revolved around it (Geocentric Model). This theory was devised from the fact that for an Earth bound observer, Earth seems to be at rest and the heavenly bodies seem to move in circles around it. The prominent persons to support Geocentrism include Aristotle and Ptolemy.
Geocentrism faced its first challenge from Coppernicus, who firmly believed in a heliocentric model of the universe (with the sun at the centre). This model did not gain public support in the Renaissance and was forgotten until Galilio gave evidence to support it with his telescope in 1611. This gave solid foundation to heliocentrism which then displaced geocentrism
1. STEADY STATE THEORY
Steady state theory was proposed by Fred Hoyle, Thomas Gold and Hermann Bondi in 1948 as an alternative to the Big Bang theory. It supported the Big Bang view of matter being created continuously in the universe keeping the average mass density roughly constant; but it states that the universe had no beginning and end contradicting the Big Bang.
Well, am not going into the details of the two models as that will include mentioning formation of baryon per cubic megaparsec and dark matters which are a teeny weeny bit difficult to understand.
As the two models contradicted each other, only one could survive. The findings of many satellites in recent times, give evidence supporting the Big Bang and the theory is accepted widely in the scientific community, leading to the demise of the steady state theory
COME AGAIN TOMORROW
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