they not even real. trees are also fake.
The idea of atoms originated in Ancient Greece when philosopher Democritus imagined that if you cut something in half enough, you would reach a piece so tiny it couldn’t be cut anymore. He named these things ‘uncuttable’, or ‘Atomos’.
He did not, however, have any experimental evidence.
Useful scientific observations came in the early 1800’s, when schoolteacher John Dalton noticed that elements always combined in whole number ratios when forming new stuff.
For example, in water, there are always two parts hydrogen and one part oxygen. This gives the famous formula, H2O. He never saw fractions of elements combining. Water was not H2.3O.
This made him realise that elements were made of tiny singular buildings blocks. If atoms didn’t exist, the ratios would be random (not consistent whole numbers).
John Dalton realised ‘stuff’ was composed of indivisible parts that combined to make new compounds. Photo credit: Kurzon, via wikimedia commons
How pollen proved atoms existed
A big breakthrough came in 1905 (surprisingly recently) from Albert Einstein himself.
In the early 1800’s, the botanist Robert Brown observed that pollen grains curiously moved on their own in water, without anything noticeably pushing them.
Einstein was actually able to create a mathematical formula that described this random movement of the pollen.
His theory stated that water molecules (made of atoms) were actually crashing into the pollen grains and jiggling them around. Einstein had created an equation that proved the existence of atoms!
Molecules of water cause pollen grains to move around randomly. Photo credit: Lookang, via Wikimedia Commons
By 1908, experimental evidence supported Einstein’s equations to be right. Atoms are real!
However, unless you are familiar with hard-core maths and physics, this proof of atoms would still look like gibberish.
What would be great is an image of an atom!
Atomic feeling
Atoms are too small to be seen with regular microscopes and light.
In the 70’s, a new futuristic microscope was created that solved this problem; the Scanning Tunnelling Microscope (STM).
Scanning Tunnelling Microscopes use a very sharp tip to ‘feel’ the surface of a solid. Photo credit: Krzysiu, via Wikimedia Commons
This is a Nobel Prize winning piece of technology that uses an incredibly sharp tip to essentially feel the surface of a sample, which gives a 3D picture of that solid. It is a bit like using your hands in the dark to get a picture of your surroundings.
Using STM, scientists have managed to actually produce images of atoms that make up solids.
An image of the carbon atoms that make up graphite (or pencil lead). Photo credit: Frank Trixler, via Wikimedia Commons
A picture tells a thousand words (or a single atom)
Scientists are forever curious and hard working, so just ‘feeling’ atoms didn’t quench their thirst to see atoms for real.
In 2018 a landmark photo was capture by David Nadlinger of a single strontium atom.
He managed to take this photo by suspending the strontium atom in a strong electric field before blasting the atom with strong lasers. The lasers causes the atom to emit light, which is captured by the camera.
The ghostly white dot suspended in space is quite remarkable when you realise it’s actually a single atom.
Charged atoms suspended in a strong magnetic field. Photo credit: Wright-Patterson AFB
From philosophy to photography
It has only taken 2000 years for our species to go from philosophical atoms, to mathematically and chemically proving their existence, to finally seeing images of them.
You now know, for certain, that your high school chemistry teacher was not wrong when they told you “tiny invisible balls make up everything”.