Hello everyone, I am Dr. Ujwalkumar Trivedi, Head of Biotechnology Department at Marwadi University Rajkot. I teach Molecular Biology to the students of M.Sc. Microbiology and Biotechnology.
The current presentation is like a history book of various discoveries that led to the development of quantum mechanics. The presentation also tries to address the debate between the radicals (supporters of quantum theory) and classical (supporters of Newtonian physics).
Labelling Requirements and Label Claims for Dietary Supplements and Recommend...
Origin of Quantum Mechanics: Scratching the back of quantum world
1. Presented by
Dr. Ujwalkumar Trivedi, Ph.D., FICS
Head
Department of Biotechnology
Marwadi University
Rajkot (Gujarat)
Scratching the Back of the Quantum
World
Date: 20/04/2020
Quarantine Classes Course 3:
Fundamentals of Thermodynamics and its Implications in Biochemistry
3. Democritus (400 BC)
His theory: Matter could
not be divided into smaller
and smaller pieces forever,
eventually the smallest
possible piece would be
obtained.
This piece would be
indivisible.
He named the smallest
piece of matter “atomos,”
meaning “not to be cut.”
10. Two thousand years
later a British chemist
and schoolteacher
brings back
Democritus’s idea of
the atom
He performed many
experiments to study
how elements join
together to form new
substances
He found that they
combine in specific
ratios (remember the
electrolysis of water)
and he supposed it was
because the elements
are made of atoms.
11. 1. Elements are composed of extremely small
particles called atoms. All atoms of a given
element are identical, having the same size,
mass and chemical properties. The atoms of one
element are different from the atoms of all other
elements.
2. Compounds are composed of atoms of more
than one element. The relative number of atoms
of each element in a given compound is always
the same.
3. Chemical reactions only involve the rearrangement
of atoms. Atoms are not created or destroyed in
chemical reactions.
2.1
12. Although the lower versions of so called steam engines were already invented in late 16th century and
early 17th century, the proper engineering took about 150 years for its efficient use in industries in
railways. Engineering worked very fine although the laws governing the motion of steam engine were
very elusive. This was specially because no one knew or even was convinced regarding the existence
of atoms. Scientific world was in a comfort zone of deterministic science i.e. to believe only what they
can see and of course atoms cannot be seen.
13. He postulated that thermal motions like the one that can be seen in
steam engines are due to random motions of particles (atoms). He
formulated the laws governing thermal motions of steam engine using
mathematics (statistical thermodynamics).
Scientific giants of those days
discarded the Boltzmann’s idea
by saying that he was just
creating fiction out of
mathematics. Scientific world
depended more on the objective
reality which was deterministic.
Ludwig Boltzmann suffered from
depression for a very long time
due to rejection of his ideas and
committed suicide in 1906. But
this was the year, scientific
world was going to change
forever.
14. Albert Einstein worked as a patent clerk in Bern where he got a lot of time to think and
ponder. This free time led him to the development of General and Special theories of
relativity. He was sadden by the news of Ludwig Boltzmann. Coincidently he stumbled
upon an 1830 paper by Scottish Botanist Robert Brown which remained largely ignored by
the scientific world.
15. In 1830, Robert Brown observed the jiggling of pollens in still water under a microscope. Although
the water was still, he could not understand what made these pollens jiggle and coined the term
“Brownian Motion/Movement”.
16. By measuring the magnitude of the jiggling and using complex
mathematics, Einstein was also able to predict the size of the
particles to a great precision.
19. Max Plank was approached by some industry people to optimize the efficiency of light bulb. He wanted
to figure out how to reduce or demolish other wavelengths (ones which are not in the visible regions)
and to enhance the visible spectrum. While thinking over this he stumbled upon the UV-Catastrophe.
Although, the intensity is
increasing with temperature
but light is not becoming
any bluer.
22. Photoelectric effect was only
possible with photons acting
as Quanta (Particles).
Previously, light was
described as wave and now
as particle and hence dual
nature of light.
23. J.J. Thomson (Discovery of
Electron)
What particle did Thomson discover?
J.J. Thomson discovered that atoms
are made of smaller negatively-
charged particles called electrons.
Thomson’s discovery was the result
of doing experiments with “cathode
ray tubes”
24. J.J. Thomson, measured mass/charge of e-
(1906 Nobel Prize in Physics)
Cathode Ray Tube Experiment
25. Thomson’s Plum Pudding Model of
Atom
Thomson did not know
how the electrons in an
atom were arranged. He
believed they were mixed
throughout an atom.
He proposed that the atom
was a sphere of positively
charged material. Spread
throughout the atom were
the negatively charged
electrons similar to plums
in a pudding or chocolate
chips in ice cream.
28. Awarded the Nobel Prize in
Chemistry for his discovery of
alpha particles, positively charged
particles emitted from radioactive
elements
Was a student of J.J. Thomson but
disagreed with the “Plum Pudding
Model”
Devised an experiment to
investigate the structure of
positive and negative charges in
the atom.
Ernest Rutherford Discovery of
Proton
30. 1. atoms positive charge is concentrated in the nucleus
2. proton (p) has opposite (+) charge of electron (-)
3. mass of p is 1840 x mass of e- (1.67 x 10-24 g)
particle velocity ~ 1.4 x 107 m/s
(~5% speed of light)
(1908 Nobel Prize in Chemistry)
Rutherford’s Gold Foil Experiment
31. The diameter of a pinhead is 100,000 times smaller than the diameter of a stadium.
Likewise the diameter of the nucleus of an atom is 100,000 times smaller than the
diameter of an atom
32. H atoms - 1 p; He atoms - 2 p
mass He/mass H should = 2
measured mass He/mass H = 4
4
2 + 9Be 1n + 12C + energy
neutron (n) is neutral (charge = 0)
n mass ~ p mass = 1.67 x 10-24 g
33.
34. Rutherford’s Planetary Model
If the electrons collapsed in to the nucleus, there will not be
an existence of atom. Niels Bohr was deeply intrigued by this
problem and the recent revelations of Max Planck regarding
the “Quanta”.
35. Ernest Rutherford Niels Bohr
The Great Marriage of Experimental and
Theoretical Physics at University of Manchester
36. Niels Bohr’s Atomic Model
It is impossible to determine the structure of an atom as
electrons just migrate in a cloud of probability.
37. Niels Bohr formed “NIELS BOHR INSTITUTE” in Copenhagen
(1920). Institute mainly did theoretical physics research and at
that time developing concepts of quantum mechanics
38. Clash of the Titans
Conservatives believed
that the world is
deterministic. Everything
can be predicted. Just
like before throwing a
ball or launching a
rocket, we can calculate
the path and time to
reach the destination
Radicals believed that
there is a fundamental
limit to know the reality.
Things cannot be
predicted at the sub-
atomic level. Quantum
world do not follow
Newtonian Mechanics
and hence Quantum
Mechanics was born.
World is Deterministic V/S World is not completely Deterministic
41. In the case of electrons in atoms, it can be stated as follows: it is impossible for two electrons of a
poly-electron atom to have the same values of the four quantum numbers: n, the principal quantum
number, ℓ, the azimuthal quantum number, mℓ, the magnetic quantum number, and ms, the spin
quantum number.
Wolfgang Pauli (Radical)
45. It says that a quantum particle doesn't exist in one state or another, but in
all of its possible states at once. It's only when we observe its state that a
quantum particle is essentially forced to choose one probability, and that's
the state that we observe. Since it may be forced into a different observable
state each time, this explains why a quantum particle behaves erratically.
This state of existing in all possible states at once is called an object's
coherent superposition. The total of all possible states in which an object
can exist -- for example, in a wave or particle form for photons that travel
in both directions at once -- makes up the object's wave function. When we
observe an object, the superposition collapses and the object is forced into
one of the states of its wave function
46.
47.
48. Thank You
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