What are we made of and where did it all come from? Such questions have pervaded the minds of scientific thinkers since ancient times and have entered all fields of enquiry, from the physical to the philosophical. Our best scientific theory today asserts that we’re made of atoms, and these atoms come in different shapes and sizes. Fundamentally, they can be described by the number of subatomic particles (protons, neutrons, and electrons) they contain (Jefferson Lab, 2012).
Neatly arranged in a grid, these different elements form the periodic table we know and love today; but it was not always this way. The story of how the periodic table of elements came to be harks back to Ancient Greece and winds its way through the enlightenment into the 20th century. It is an unfinished story of which we are at the frontier of today: in search of dark matter and the ultimate answer to what the universe is made of. We may never know for sure exactly what everything in existence consists of, but it’s a pursuit our earliest ancestors would be proud to see us follow.
Thales was first in the ancient Greek-speaking world to postulate about the origins of all material things. He theorised that all matter in the universe was made up of just one type of substance – water – and any other forms of solids, liquids and gases were just derivatives thereof. This idea was not initially opposed, given Thales was one of the earliest of the Ancient Greeks to pursue such questions of a scientific nature. Afterall, he’s remembered today as the “Father of Science” in the Western world. As Thales was from Miletus, a city on the coast of the Ionian Sea in modern day Türkiye and part of Magna Graecia in the 6th cent BC, it is not hard to imagine that water was a crucial aspect in trade, agriculture, and daily life at the time. However, this seemed to oversimplify the matter to some of his contemporaries.
Empedocles, who was considered more a magician than a philosopher, revised this mono-elemental theorisation in the 5th Century BC. He proposed four basic substances from which all others were made (Mee, 2020). We know them today famously as the four classical elements: Earth, Air, Water and Fire. This asserted a fundamental principle of “fourness”, encompassing the cardinal directions in the Western world during this time. Interestingly, concurrent to this other traditions such as those in China acknowledged five elements and compass points instead.
A generation later to Empedocles’ work, Plato embraced his “fourish” formulation. Being heavily influenced by mathematics as the medium through which we make reason of the natural world, Plato related each of these elements to a mathematical object: a convex, regular polyhedron in three-dimensional Euclidean space, otherwise known as a Platonic solid. Earth was associated with the cube, air with the octahedron, water with the icosahedron, and fire with the tetrahedron. Lastly, the most complicated solid, the dodecahedron – itself made up of composite regular polygons – was associated with the makeup of the constellations and the Heavens themselves, their workings said to be unfathomable by human minds (Ball, 2004).
His student, Aristotle, ran with this idea and devised a clever way to break up the elements based on their "qualities”, akin to a first periodic table. These binary roles were hot and cold, wet and dry, with an element containing just two of these qualities each. According to Aristotle, each of these elements could be converted to the other by inverting one of their qualities, seemingly bringing about an early form of alchemy. To these four elements, he also appended a fifth - aether or “pure air” - to fill the expanses of the heavens, which also became associated with the fifth Platonic solid.
In the Western World, Aristotle’s word was taken as doctrine for a very long time owing greatly to the fall of Rome and the cultural instability thereafter. Where Europe plummeted into the Dark Ages with a reverence for the scholars of antiquity, scientific and literary endeavour flourished in the Middle East – the word alchemy itself having etymologically Arabic roots. It was not until the late 17th century that the likes of Galileo, Newton, and Descartes revived Western scientific pursuit, and sought to understand how the natural world arranged itself.
In the 18th century, new discoveries were being made on the frontiers of science in major cities throughout Europe. In 1772, in Paris, Antoine Lavoisier began work on combustion of materials like phosphorus and sulphur. Lavoisier concluded that if something decomposes into simpler substances, then it is not an element. For example, while water can be turned into a gas when passed over hot iron and is therefore not an element, oxygen and hydrogen are indeed elemental.
English chemist John Dalton took after Lavoisier and in 1808 began to arrange elements spatially into a chart, accounting for their various properties. In Strasbourg 1827, Wolfgang Döbereiner recognised that groups of threes arose from the list of elements which behaved similarly, known as “Döbereiner's triads" (Free Animated Education, 2023). John Newlands in 1866 put forward the “Law of Octaves”. Elements with similar properties ended up at regular intervals, dividing the elements into seven groups of eight – hence octaves. However, this method of dividing up the elements broke down in some special cases.
Now turning to St. Petersburg, Russia, in February of 1869. Dmitri Mendeleev sits at his desk, with a mess of cards covering the surface of his working space. The professor of chemistry rearranges these elemental cards like a jigsaw puzzle, arranging and rearranging them to align them in accordance with their properties. Supposedly after coming to him in a dream, a pattern emerged. Mendeleev saw the ability for the simple tabulation of the elements based on their atomic number and hence their common properties. This newfound tool, based on Lavoisier’s work a century prior, allowed for the prediction of properties of elements which had not even been discovered yet. Elements which Mendeleev believed to exist, even though they presented as empty gaps in the grid structure of the periodic table. Within just twenty years, Mendeleev’s prediction of the existence of such elements like gallium, scandium, and germanium had been validated with experimental fact. All of this was predicted without knowledge of the true reason for similarities of elemental properties – the electron shell arrangement at a subatomic level. Mendeleev had totally changed the way chemists viewed their discipline and has been immortalised for perhaps the greatest breakthrough work in the history of chemistry (Rouvray, 2019).
Today we recognise that all the elements in the universe have origins in the high-pressure hearts of stars. Like a hot furnace, they churn out heavier and heavier elements under their immense internal pressures. Once this life cycle comes to an end, the star erupts into a fiery supernova, releasing even more of the heavier elements we see further down the periodic table. In the last 75 years, scientists have added an additional 24 elements to the periodic table, some of which are so difficult to produce that their half-lives last only a few fractions of a millisecond before decaying away to nothing (Charley, 2012).
This begs the question; how do we find new elements? Elements can be created via either fission, splitting apart a heavier atom, or fusion, binding two bodies of atoms together. The heavier an element, that is, the more protons and neutrons in its nucleus, the more unstable it is. Hence it is with great difficulty that scientists attempt to churn out new elements from large particle accelerators, by colliding and combining elements into new ones (Chheda, 2023).
The story of physical matter is just one aspect in the search for what “everything” is made of. Dark matter and dark energy – so named because they do not interact with light – have been found to drive the expansion of the universe and the rotation speeds of galaxies. We know remarkably little about these substances, given that they make up around 95% of the total mass of the universe! Without a doubt, we have only just begun the journey to find out what makes up the universe around us.
References
Chheda, R. (2023, March 31). Can we add new elements to the periodic table? Science ABC. https://www.scienceabc.com/pure-sciences/can-we-add-new-elements-to-the-periodic-table.html
Charley, S. (2012). How to make an element. PBS.
https://www.pbs.org/wgbh/nova/insidenova/2012/01/how-to-make-an-element.html
Free Animated Education. (2023, February 10). Perfecting the periodic table [Video]. YouTube. https://www.youtube.com/watch?v=7tbMGKGgCRA&ab_channel=FreeAnimatedEducation
Jefferson Lab. (2012, November 20). The origin of the elements [Video]. YouTube.
Ball, P. (2004). The elements: A very short introduction. Oxford University Press.
Mee, N. (2020). Earth, air, fire, and water. In Oxford University Press eBooks (pp.
16–23). https://doi.org/10.1093/oso/9780198851950.003.0003
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