Lavoisier repeated the experiment again, substituting mercury for tin, and found that the same happened. He discovered the water rose one-fifth of the way into the glass, leading Lavoisier to conclude that air itself is a mixture, with one-fifth of it having combined with the tin, yet the other four-fifths did not, showing that air was not an element. After the flask cooled, he inverted it and opened it underwater. A grayish ash appeared on the surface of the melting tin, which Lavoisier heated until no more ash formed. For example, it was believed that lead could be made into gold.Īlchemy's problem was exposed by Antoine Lavoisier when he heated metallic tin in a sealed flask. Alchemy was based on the belief that since everything was made of only four elements, you could transmute a mixture into another mixture of the same type. This belief was very popular in the medieval ages and introduced the science of alchemy. A fire, shown by Lavoisier to be a chemical reaction and not an element.Įmpedocles proposed that there were four elements, air, earth, water, and fire and that everything else was a mixture of these. Atoms are different in their size, their shape, and their weight.Īlchemy Although alchemy was futile, the alchemists did come up with several useful methods, including distillation (shown here).
Solid substances might be composed of atoms with numerous hooks, by which they connect to each other, while the atoms of liquid substances possess far fewer points of connection.ĭemocritus proposed 5 points to his theory of atoms. A smooth substance, for instance, might be composed of primarily smooth atoms, while a rough substance is composed of sharp ones. All other properties, he argued, could be explained in terms of the three primary properties. It remained for him to account for the properties of atoms, and how they related to our experiences of objects in the world.ĭemocritus proposed that atoms possessed few actual properties, with size, shape, and mass being the most important. Their indestructibility provided a retort to Zeno, and the void allowed him to account for plurality, change, and movement. In response to these ideas, Democritus posited the existence of indestructible atoms that exist in a void. Zeno attempted to prove Parmenides' point by a series of paradoxes based on difficulties with infinite divisibility. Parmenides argued against the possibility of movement, change, and plurality on the premise that something cannot come from nothing. He proposed the existence of indivisible atoms as a response to the arguments of Parmenides and the paradoxes of Zeno. The earliest known proponent of anything resembling modern atomic theory was the ancient Greek thinker Democritus. The Greek Theorists A bust of Democritus (or Democrites), who came up with the idea of indivisible atoms. Development of an idea and refinement through testing is shown more in the understanding of atomic structure. It is fundamental to the understanding of science that science is understood to be a process of trial and improvement and represents the best known at the time, not an unerring oracle of truth.
Why Is The History Of The Atom So Important? 1 Why Is The History Of The Atom So Important?.