When did the world knew that the Atom is the smallest thing in the world?

Answer 1

It isn't

It is comprised of a neutrons, electrons and protons
The existence of atoms was however postulated by the Greek Democritus about 400B.C.

Answer 2

The actual real concept of the atom came into being only in the past century.
In the Days of Einstein =the atoms were not exactly understood.It was realized later that the atom was not indivisible but could actually be split.The atomic bomb was the proof of the pudding.
And at present there are many theories about what material makes up the components of the Atom.
Democritus postulated that there exist a substance which he called atom.The word Atom in Greek means that which cannot be divided. He knew that concrete materials such as stones,wood ,ice etc could be divided.
What he really alluded to as indivisible substance by natural means was not the of mass that we know today as atoms that can be divided,but actually he understood that it was a substance of space.That substance of space was what he called an indivisible particle structures which the Greek word ATOM describes.
So The Idea of the Aether which was primitively postulated by Aristotle ,was really explained by Democritus as being the smalest indivisible granular substance of the Universe.
To day at present scientists call it dark matter.The reason is because its the smallest volume of the Universe which is not visible and cannot be shadowed. This phenomenon is now explained in the Quantron theory of the Universe.

Answer 3

While, as pointed out here, Atomic theory and concepts go back hundres or more in years, it is NOT the smallest thing.

MODERN theories include QUARKS as the smallest building block of the parts of an atom as well as STRINGS making up all things, including QUARKS.

Of course all this is theoretical.

Answer 4

Atom were postulated thousands of years ago.
Modern physics knows that atoms are made up of protons,neutrons and electrons.
These particles are made up of entities known as quarks
Quarks are likely fundamental particles that are the result of the quantum effect on space.
Quarks may have a smaller component but that has not been determined yet.

Answer 5

"Atom" is apparently derived from the Greek "unsplittable", but I don't think that the Greeks understood atoms in any detail and merely used them theoretically as building blocks... or perhaps they didn't know and atom was just a word they had which was later used.

Answer 6

in 1986

Answer 7

The first philosophical statements relating to an idea similar to atoms was developed by Democritus in Greece in the fifth century BCE around 450 BCE. The idea was lost for centuries until scientific interest was rekindled during the Renaissance Period.

Father of modern atomism was a Jesuit priest, Rudjer Boscovich, who based his atomism mostly on classical mechanics (Newtonian mechanics) and published it in 1758. The theory was further developed by Amedeo Avogadro, his brother Johann Avogadro and the developers of the kinetic theory of gases such as James Clerk Maxwell and physicist Ludwig Boltzmann. Boscovich was regarded as the father of modern atomic theory by Faraday, Mendeleev, Maxwell, and Kelvin, who observed that his and the work of others' were "all developments of Boscovich's theory pure and simple."


Various atoms and molecules as depicted in John Dalton's A New System of Chemical Philosophy (1808).In 1803, John Dalton used the concept of atoms to explain why elements always reacted in simple proportions, and why certain gases dissolved better in water than others. He proposed that each element consists of atoms of a single, unique type, and that these atoms could join to each other, to form compound chemicals.

In 1897, JJ Thomson, through his work on cathode rays, discovered the electron and its subatomic nature (i.e., its lightness compared with the mass of atoms), which destroyed the concept of atoms as being indivisible units. Later, Thomson also discovered the existence of isotopes through his work on ionized gases.

Thomson believed that the electrons were distributed evenly throughout the atom, balanced by the presence of a uniform sea of positive charge. However, in 1909, the gold foil experiment was interpreted by Ernest Rutherford as suggesting that the positive charge of an atom and most of its mass was concentrated in a nucleus at the center of the atom (Rutherford model), with the electrons orbiting it like planets around a sun. In 1913, Niels Bohr added quantum mechanics into this model, which now stated that the electrons were locked or confined into clearly defined orbits, and could jump between these, but could not freely spiral inward or outward in intermediate states.

In 1926, Erwin Schrodinger, using Louis DeBroglie's 1924 proposal that all particles behave to an extent like waves, developed a mathematical model of the atom that described the electrons as three-dimensional waveforms, rather than point particles. A consequence of using waveforms to describe electrons, pointed out by Werner Heisenberg a year later, is that it is mathematically impossible to obtain precise values for both the position and momentum of a particle at any point in time; this became known as the uncertainty principle. In this concept, for any given value of position one could only obtain a range of probable values for momentum, and vice versa. Although this model was difficult to visually conceptualize, it was able to explain many observations of atomic behavior that previous models could not, such as certain structural and spectral patterns of atoms bigger than hydrogen. Thus, the planetary model of the atom was discarded in favor of one that described orbital zones around the nucleus where a given electron is most likely to exist.

Answer 8

TheBoxSeat ! has a point.I agree with him.