The 2,400-year search for the atom - Theresa Doud

Potraga za atomom stara 2400 godina - Tereza Daud (Theresa Doud)

Prevodilac: Stefan Zrnović Lektor: Mile Živković

What do an ancient Greek philosopher

Šta jedan starogrčki filozof

and a 19th century Quaker

i Kveker iz 19. veka

have in common with Nobel Prize-winning scientists?

imaju zajedničko sa naučnikom i dobitnikom Nobelove nagrade?

Although they are separated over 2,400 years of history,

Iako ih deli više od 2400 godina u istoriji,

each of them contributed to answering the eternal question:

svaki od njih je doprineo odgovoru na večno pitanje:

what is stuff made of?

od čega su napravljene stvari?

It was around 440 BCE that Democritus first proposed

Bilo je to oko 440 g.p.n.e kada je Demokrit prvi put predložio

that everything in the world was made up of tiny particles

da je sve na svetu sačinjeno od malih čestica

surrounded by empty space.

okruženih praznim prostorom.

And he even speculated that they vary in size and shape

Čak je zagovarao da one variraju u veličini i obliku

depending on the substance they compose.

u zavisnosti od supstance koju sačinjavaju.

He called these particles "atomos," Greek for indivisible.

Nazvao je ove čestice "atomos", po grčkoj reči za nevidljivo.

His ideas were opposed by the more popular philosophers of his day.

Njegovim idejama su se suprotstavljali popularniji filozofi njegovog vremena.

Aristotle, for instance, disagreed completely,

Aristotel se, na primer, nije uopšte složio,

stating instead that matter was made of four elements:

govoreći da je materija stvorena od četiri elementa:

earth, wind, water and fire,

zemlje, vetra, vode i vatre,

and most later scientists followed suit.

a kasnije su ovu tezu pratili naučnici.

Atoms would remain all but forgotten until 1808,

Atomi su ostali zaboravljeni do 1808. kada je učitelj Kveker

when a Quaker teacher named John Dalton sought to challenge Aristotelian theory.

po imenu Džon Dalton pokušao da ispita Aristotelovu teoriju.

Whereas Democritus's atomism had been purely theoretical,

Dok je Demokritov atomizam bio skroz teoretski,

Dalton showed that common substances always broke down into the same elements

Dalton je pokazao da su se zajedničke supstance uvek sastojale

in the same proportions.

od istih elemenata u istim proporcijama.

He concluded that the various compounds

Zaključio je da su razna jedinjenja

were combinations of atoms of different elements,

bila kombinacije atoma različitih elemenata,

each of a particular size and mass

svaki posebne veličine i mase

that could neither be created nor destroyed.

koja ne bi mogla biti stvorena, niti uništena.

Though he received many honors for his work,

Iako je dobio mnoga odlikovanja za svoj rad,

as a Quaker, Dalton lived modestly until the end of his days.

kao Kveker, Dalton je živeo skromno do kraja svog života.

Atomic theory was now accepted by the scientific community,

Atomsku teoriju je sada prihvatila naučna zajednica,

but the next major advancement

ali sledeći značajni napredak

would not come until nearly a century later

neće doći do skoro jednog veka kasnije

with the physicist J.J. Thompson's 1897 discovery of the electron.

sa otkrićem elektrona 1897. fizičara Džej Džej Tomopsona.

In what we might call the chocolate chip cookie model of the atom,

Onim što bismo nazvali modelom atoma nalik na čokoladni biskvit,

he showed atoms as uniformly packed spheres of positive matter

on je pokazao atome kao ujednačeno spakovane sfere pozitivne materije

filled with negatively charged electrons.

ispunjene negativno naelektrisanim elektronima.

Thompson won a Nobel Prize in 1906 for his electron discovery,

Tompson je osvojio Nobelovu nagradu 1906. godine za svoje elektronsko otkriće,

but his model of the atom didn't stick around long.

ali njegov model atoma nije trajao dugo.

This was because he happened to have some pretty smart students,

Razlog ovome je taj što je imao prilično pametne studente,

including a certain Ernest Rutherford,

uključujući i Ernesta Raterforda,

who would become known as the father of the nuclear age.

koji će postati poznat kao otac nuklearne ere.

While studying the effects of X-rays on gases,

Dok je proučavao efekate ultraljubičastih zraka na gasove,

Rutherford decided to investigate atoms more closely

Raterford je odlučio da bliže istraži atome,

by shooting small, positively charged alpha particles at a sheet of gold foil.

ispaljujući male, pozitivno naelektrisane alfa čestice u parče zlatne folije.

Under Thompson's model,

Pod Tompsonovim modelom,

the atom's thinly dispersed positive charge

tanko raspoređeno pozitivno naelektrisanje atoma

would not be enough to deflect the particles in any one place.

ne bi bilo dovoljno da se čestice odbiju na bilo koje mesto.

The effect would have been like a bunch of tennis balls

Efekat bi delovao poput gomile teniskih loptica

punching through a thin paper screen.

koje udaraju kroz tanki papirni ekran.

But while most of the particles did pass through,

Ali dok je većina čestica prolazila,

some bounced right back,

neke su se odbijale nazad,

suggesting that the foil was more like a thick net with a very large mesh.

naznačujući da je folija bila više poput debele mreže sa velikim proredom.

Rutherford concluded that atoms consisted largely of empty space

Raterford je zaključio da su se atomi većinom sastojali od praznog prostora

with just a few electrons,

sa samo nekoliko elektrona,

while most of the mass was concentrated in the center,

dok je većina mase skoncentrisana u centru,

which he termed the nucleus.

kojeg je nazvao nukleusom.

The alpha particles passed through the gaps

Alfa čestice su prolazile kroz otvore

but bounced back from the dense, positively charged nucleus.

ali su se odbijale o gusto, pozitivno naelektrisano jezgro.

But the atomic theory wasn't complete just yet.

Ali atomska teorija još nije bila završena.

In 1913, another of Thompson's students by the name of Niels Bohr

1913. godine, drugi Tompsonov učenik po imenu Nils Bor

expanded on Rutherford's nuclear model.

proširio je Raterforodov nuklearni model.

Drawing on earlier work by Max Planck and Albert Einstein

Vodeći se prethodnim radom Maksa Planka i Alberta Ajnštajna,

he stipulated that electrons orbit the nucleus

predvideo je da eletroni kruže oko nukleusa

at fixed energies and distances,

na fiksnim energijama i razdaljinama,

able to jump from one level to another, but not to exist in the space between.

da mogu da skoče sa jednog nivoa na drugi, ali ne i da postoje u međuprostoru.

Bohr's planetary model took center stage,

Borov planetrani model je došao u centar pažnje

but soon, it too encountered some complications.

ali uskoro je i on naišao na neke komplikacije.

Experiments had shown that rather than simply being discrete particles,

Umesto da su prosto diskretne čestice, eksperimenti su pokazali

electrons simultaneously behaved like waves,

da su se elektroni u isto vreme ponašali kao talasi,

not being confined to a particular point in space.

nisu ograničeni na određenu tačku u prostoru.

And in formulating his famous uncertainty principle,

Tokom forumlisanja svog principa neodređenosti,

Werner Heisenberg showed it was impossible to determine

Verner Hajzenberg je pokazao da je nemoguće odrediti

both the exact position and speed of electrons

i tačnu poziciju i brzinu elektrona

as they moved around an atom.

tokom pomeranja oko atoma.

The idea that electrons cannot be pinpointed

Ideja da se elektronima lokacija ne može tačno utvrditi,

but exist within a range of possible locations

već postoje u opsegu mogućih lokacija,

gave rise to the current quantum model of the atom,

dovela je do trenutnog kvantnog modela atoma,

a fascinating theory with a whole new set of complexities

fascinantne teorije sa čitavim novim skupom problema

whose implications have yet to be fully grasped.

čije implikacije tek treba da se istraže.

Even though our understanding of atoms keeps changing,

Iako se naše shvatanje atoma menja,

the basic fact of atoms remains,

osnovno shvatanje atoma ostaje,

so let's celebrate the triumph of atomic theory

pa hajde da slavimo trijumf atomske teorije

with some fireworks.

vatrometima.

As electrons circling an atom shift between energy levels,

Dok se elektroni koji kruže oko atoma prebacuju između energetskih nivoa,

they absorb or release energy in the form of specific wavelengths of light,

oni apsorbuju ili oslobađaju energiju u obliku specifičnih svetlosnih

resulting in all the marvelous colors we see.

talasnih dužina, što za posledicu ima predivne boje koje vidimo.

And we can imagine Democritus watching from somewhere,

Možemo da zamislimo Demokrita kako posmatra odnekud

satisfied that over two millennia later,

zadovoljan što se nakon više od dva milenijuma,

he turned out to have been right all along.

ispostavilo da je sve vreme bio u pravu.