Quantum Mechanics: Introduction to Quantum physics.
At Micro level universe do not obey the laws of physics
I already told you about Planks length in part 16 and about size comparison of an atom with that of its nucleus in part 18. And now you already have an idea of the vastness of this universe as well as its smallest things and building blocks. But the problem is that at the macro level all that we see from ourselves to all the various things on earth, and then on an even bigger scale, stars and galaxies, all work under well defined laws. But at micro level on the smallest scale i.e at the elementary particles level the universe is strange. There it do not obey the laws of physics as we know.
Evolution of Atomic theory
The first person who gave the concept of the smallest particle was Democritus in 460 BC. He says cut anything until get very small that you cannot cut more. That he called “atomos” In Greek “a” means “Not” and “tomos” means “Cut” i.e indivisible that you cannot cut more. Then in 1897 J.J.Thomson discovered Electron by cathode rays tubes. Then exactly after 14 years in 1911 Ernest Rutherford with his gold foil experiment passing Alpha particles gave the idea that atoms have their charge concentrated in a tiny nucleus, and electron having a -ve charge around it and thereby pioneered the Rutherford model of the atom.