The Newtonian worldview was utterly changed by developments in atomic theory in the 19th
and 20th centuries. Do you agree?
It is without apprehension that many contributions have been made towards the development of
the atomic theory which challenged the original ideology set in place by Newtonian law. Many
minds including John Dalton, J.J Thomson, Albert Einstein, Ernest Rutherfors, Niels Bohr and
James Chadwick operated in tandem to one another to bring about these changes. These
supplements in the evolution of the atomic theory abolished the boundaries of knowledge set in
place by those who favoured and idolised the Newtonian worldview and offered a more in
depth understanding of matter and energy. Although I agree that the numerous contributions
that were proposed by these men allowed for a substantial advancement in the concept of the
atomic theory they did not ‘utterly’ change every aspect of the Newtonian worldview.
Abstracts formulated through Newton’s work established a foundation which was able to be
expanded on, preventing the atomic theory from developing without any Newtonian input.
Newton based his theories on mathematics, distinguishing himself from other
philosophical fields. This unique perspective of viewing the unknown forces of the world at
play in a mathematical sense offered alternative solutions that could be logically explained
through the three laws of motion. Throughout his studies Newton devised various hypotheses
about the properties which constituted the structure of matter, claiming that they were
mechanical in nature as they consist of small solid masses which are in constant motion.
Newton visualised these masses, which we know today as being atoms, to be a clustered
structure of matter formed from the particle bodies ability to stick together by strong forces of
attraction
[1]
. Newton devised the hypotheses of conformability and simplicity to account for
the fact that even though gravitational forces which drove the heavenly bodies were governed
by universal attraction the components of atoms and molecules are instead driven by Coulomb
forces which are combined of both attractive and repulsive forces. Newton made assumptions
about the presence of attractive forces which explained the particle bodies tending towards one
another
[1]
which arose from an impulsive mechanism that was unknown to him at the time.
Newton believed that all phenomena could be explained in terms of subtle fluids that were
referred to as the aether, which permeated the whole universe. This aether explained how
forces such as gravity and magnetism were able to be distributed across the universe in the form
of vibrations. The wave pattern was created through the repulsive forces that were in play
between distant particles propelling themselves away from one another and eliciting the
transmission of a shock wave [2] . Newton was able to generate a rationale for the very
1.
Philip Yock, "Newton’S Hypotheses On The Structure Of Matter", Arxiv.Org, 2020; available from
https://arxiv.org/pdf/1807.05486.pdf; accessed 15 December 2020.
2.
John Henry, A Short History of Scientific Thought (London, 2012).
1
questions that plagued the brilliant minds around him fabricating a culture that tried to build
upon his ideologies rather than questioning them. Despite the fact that it seemed that many had
accepted the authenticity of Newton's work there were those in the 19th and 20th century who
found fault in his hypotheses and sought to uncover the truth.
Newtonian atomists used his teachings to ‘explain properties of bulk matter such as
coagulation and chemical combination, by appeal to inter - atomic forces’
[1]
. In 1803 John
Dalton formulated his atomic theory through the knowledge that emerged from Newtonian
atomistic theory of gases. Dalton adapted the observations presented within the Principia and
through experimentation clarified the law of partial pressures and the presence of the
homogenous mixture of gases in the atmosphere. Dalton extended his theory of gases into his
understanding of chemical elements assuming like gases that they were composed of ‘ultimate
particles’ or atoms. Further experimentation with these particles allowed him to predict the law
of multiple proportions and law of equivalent proportions. The combination of his laws resulted
in Dalton anticipating the matter was in fact composed of extremely small particles called atoms
which were indivisible, indestructible and identical for a given element. It is clear from Dalton's
research that despite the fact that he made substantial progress in identifying the properties of
atoms and drove the discussion for the atomic theory his work did not ultimately diverge from
that of Newtons. It was Newton's previous teachings which allowed Dalton to question their
legitimacy and build upon the knowledge. It is this fact alone that prevents me from agreeing
with the concept that in the generation of Dalton's atomic theory he did so without the use of
the Newtonian views.
In 1897 J.J Thomson discovered the electron through his use of a cathode ray tube. He
discovered that the rays emitted from the cathode were composed of light, negatively charged
particles in which he called corpuscles, which would later be termed as electrons. It was
through further investigation with neon gas that he was able to account for the presence of
positively charged particles. J.J Thomson realised through the system of electrical deflection
that the previously stated model of the atom did not take into account the presence of these
charge particles and as a result he established his plum pudding model of the atom which
described it as being a sphere of negatively charged electrons within positively charged
particles distributed throughout. The way in which J.J Thomson displayed his version of the
atom enabled the electrical property of reflection and attraction to be explained as the like
charges were repelling one another. Although J.J Thomson's model deferred from formerly
accounted structures of the atom it still followed the basic principles set by Newton, where he
described the presence of attractive and repulsive forces present between particle bodies. Even
though the exact mechanism behind these forces were unknown to Newton, and as a result
deemed as being a natural phenomena, the discovery of negatively and positively charged
1.
Alan Francis Chalmers, The Scientist's Atom And The Philosopher's Stone (Dordrecht, 2009)
2
particles were able to illustrate the operation of this property.
In 1905 Albert Einstein was able to mathematically prove the existence of atoms by
forming an equation from the hybridisation of Planck’s notion of quanta alongside the wave
particle duality nature of light. Throughout his studies Einstein applied a more statistical
approach to the random motions of Newtonian atoms and as a result he gained a greater
understanding about the photoelectric effect, which is when electrically charged particles are
released from a material as a result of the absorption of electromagnetic radiation [1] . Using his
insight into Robert Brown’s discovery of Brownian motion Einstein was able to calculate the
average distance that a particle could travel in a given time and as a result one could determine
the size of the atom
[2]
. Like Newton, Albert Einstein took a mathematical approach to
understanding the atomic theory however it was more his disdain for Newton's principles
which drove Einstein to develop his theories rather than a mutual appreciation for the workings
of the world.
Ernest Rutherford, a former student of J.J Thomson carried out a series of experiments
where he projected a series of alpha atoms into thin gold foils believing that they would travel
straight through. Despite the fact that some of the alpha atoms followed his predictions, many
were deflected at an angle while others were reflected back along their original pathway. The
course in which these particles travelled suggested that they ‘encountered a large and
concentrated positive charge’
[3]
, which massively contradicted the model suggested by J.J
Thomson. The large positively charged core repelled the like charge of the alpha particles
creating a large reflection when they come in close contact or even a recoil back along the same
pathway if they collided head on. The core had to be small in order for some of the alpha
particles to pass through without being influenced. These results caused Rutherford to question
the model constructed by Thomson as even though he proved the presence of negatively
charged particles within the atom their anatomical position did not account for their influence
over the alpha particles. Rutherford concluded that ‘atoms were made of a relatively large
positively charged core, the nucleus, surrounded by a number of relatively small orbiting
electrons’ [3] . The angles at which Rutherford’s alpha particles deviated highlights the presence
of Coulomb forces which was hinted at by Newton and explains how particles are attracted or
1.
J. Gregory Stacy and W. Thomas Vestrand, Encyclopedia Of Physical Science And Technology, 3rd
ed., 2003.
2.
Paul Bowersox, "Albert Einstein And The Most Elemental Atomic Theory -- ANS / Newswire",
Ans.Org, 2012; available from
https://www.ans.org/news/article-969/albert-einstein-and-the-most-elemental-atomic-theory/#:~:text
=Einstein%20also%20in%201905%20mathematically,use%20of%20statistics%20and%20probabil
ity.&text=Atomic%20theory%20says%20that%20any,always%20in%20random%2C%20ceaseless%
20motion.; accessed 17 December 2020.
3.
Peter J. Bowler & Iwan Rhys Morus, Making Modern Science: A Historical Survey (Chicago, IL,
2005)
3
repelled on the basis of their electric charge. Ernest made great developments in our
understanding of the atom, without conflicting the ideas proposed by Newton and although this
may not have been his intention, to propagate a Newtonian view, the assumptions that he made
were confirmed in more detail through Rutherford's experiments.
The new model of the atom designed by Ernest Rutherford contained a few
shortcomings which were tackled by the Danish physicist, Niel Bohr. According to
Rutherford's model the energy radiating from the central positive core would cause the
surrounding negative energy to lose momentum and spiral into the core preventing the atom
from existing for a long period of time. Bohr proposed a model which housed a central nucleus,
through which electrons orbited, that could emit ‘distinct packets of energy, each with a
distinctive frequency’
[1]
in order to explain the atom's ability to maintain its stability. This
emission of energy provided chemists with an understanding as to why there were noticeable
and unique absorption and emission spectrum for the different elements. The notion devised by
Bohr was molded from Planck’s quantum suggesting that the energy which was released in the
form of a photon (light), needed to correspond to ‘discrete quantized levels’ [2] otherwise they
were found in a rested state. In conjunction to the formation of the new atomic model Bohr
discovered through the use of a microscope that the photon does not travel as a discrete particle
and has wave-like properties, making the determinants of its direction and exact location
impossible giving rise to Heisenberg's Uncertainty Principle. The concept of light travelling in
wave-like patterns is founded from Newton's belief that particles of light create waves within
the aether causing them to follow this motion [3] . Although the reasoning that was suggested by
Newton as to why light travels in wave-like motion was inaccurate the concept itself is true and
Bohr was able to prove the travel path in his experiments. It is evident through the progression
of time that the atomic theory is continuously being matured but there is still evidence of
Newton's philosophies littered throughout modern work. It is clear that Newton’s teachings can
not be fully abandoned in scientist's quest for enlightenment.
James Chadwick is the last piece in the atomic theory puzzle that will be discussed
within this essay. Chadwick regarded the experiment carried out by Irène and Frédéric
Joliot-Curie where they bombarded beryllium, which was obstructed by paraffin wax, with
alpha particles and realised that if both ‘energy and momentum were to be conserved’ [4] then
1.
Peter J. Bowler & Iwan Rhys Morus, Making Modern Science: A Historical Survey (Chicago, IL,
2005)
2.
Peter Dear, The Intelligibility Of Nature: How Science Makes Sense Of The World (Chicago, 2006).
3.
Isaac Newton, "Opticks: Or, A Treatise Of The Reflections, Refractions, Inflexions And Colours Of
Light", Library.Si.Edu, 1704; available from
https://library.si.edu/digital-library/book/optickstreatise00newta; accessed 17 December 2020.
4.
John D. Rogers, "The Neutron's Discovery - 80 Years On", Physics Procedia 43 (2013): 1-9.
4
the protons that entered the ionization chamber appeared as a result of the presence of a heavy
particle acting on it. In 1932 following further experimentation Chadwick was able to conclude
that the particles were neutral with regards to their charge, hence the name neutron, and were
heavier than the protons which is how they were able to effectively push the protons from the
paraffin wax. James Chadwick's discovery was one which was most outside the realm of
thought for Isaac Newton. The prospect of neutral bodies existing within these minute masses
did not seem to be considered in Newton’s work, which alone highlights a change within the
Newtonian worldview as a new concept is being manifested within the atomic theory.
It is without apprehension that throughout the progression of the atomic theory in the
19th and 20th century there has been a steady progression away from the use of Newtonian
laws and understanding which has allowed for a more in depth and multidimensional
recognition of atomic mechanics. I do not believe however that there has been an utter change
with the way in which we observe the atom. Newton entrenched a foundation of understanding
which allowed for the building of new found ideas. A lot of his propositions were accurate in
their approach which is why the men mentioned above were able to refine them in a way that
made the methodology applicable to the evidence obtained through experimentation. Faults can
be seen in Newton's work, as with many scientists, but without his contributions I believe the
advancements made in atomism wouldn’t be as progressive or insightful as they allowed for
alternative processes to be conjured.
5
References
1. Yock, Philip. "Newton’S Hypotheses On The Structure Of Matter". Arxiv.Org, 2020.
https://arxiv.org/pdf/1807.05486.pdf.
2. Henry, John. A Short History Of Scientific Thought. London, 2012.
3. Chalmers, Alan Francis. The Scientist's Atom And The Philosopher's Stone. Dordrecht,
2009.
4. J. Bowler, Peter, and Iwan Rhys Morus. Making Modern Science: A Historical Survey.
Chicago, IL, 2005.
5. Stacy, J. Gregory, and W. Thomas Vestrand. Encyclopedia Of Physical Science And
Technology. 3rd ed., 2003.
6. Bowersox, Paul. "Albert Einstein And The Most Elemental Atomic Theory -- ANS /
Newswire". Ans.Org, 2012.
https://www.ans.org/news/article-969/albert-einstein-and-the-most-elemental-atomic-the
ory/#:~:text=Einstein%20also%20in%201905%20mathematically,use%20of%20statisti
cs%20and%20probability.&text=Atomic%20theory%20says%20that%20any,always%2
0in%20random%2C%20ceaseless%20motion.
7. Dear, Peter. The Intelligibility Of Nature: How Science Makes Sense Of The World.
Chicago, 2006.
8. Newton, Isaac. "Opticks: Or, A Treatise Of The Reflections, Refractions, Inflexions
And Colours Of Light". Library.Si.Edu, 1704.
https://library.si.edu/digital-library/book/optickstreatise00newta.
9. Rogers, John D. "The Neutron's Discovery - 80 Years On". Physics Procedia 43
(2013): 1-9.
6