-
450 BCE
Empedocles 450BC
In 450BC, a man named Empedocles came up with a model for what matter was. This model said that matter was composed of four elements. These elements were earth, air, fire, and water. His model suggested that these elements mixed to form substances. He conducted experiments to check his work and came up with theories such as air had to be matter even if you can't see it because it takes up space. -
Period: 450 BCE to
Matter Timeline
-
400 BCE
Democritus about 400BC
In 400BC, a man named Democritus suggested a new theory on what matter was. His model said that matter was made of tiny particles that could not be broken down. He then went on to name these particles atoms and his model was revolutionary for the time. He suggested that different elements were made up of different atoms. Sadly, Socrates did not accept Democritus' model therefore it was never widely accepted. -
350 BCE
Aristotle 350BC
In 350BC, a man named Aristotle had announced that he believed more in Empedocles' theory than in Democritus' theory. He had not done any experiments himself although he created a massive impact that made people believe in Empedocles' theory for almost 2000 years. -
500
Alchemists 500-1600 A.D.
Throughout the years of 500-1600, alchemists created some new theories and equipment. First, they believed that metal grew like plants and then ripened into gold. They conducted many experiments to try and make gold from cheap metals. Alchemists created many symbols that we now call elements and compounds They also invented many lab tools that we use today such as beakers and filters. They found many new substances and still believed in the four-element model. -
Robert Boyle 1650
After almost 2000 years of people believing in the four-element model, A man named Robert Boyle came forward and disagreed with Empedocles' model in 1650. Boyle created a new definition for the word element and claimed that elements were unmutated bodies. His new definition stated that elements were pure substances that could not be broken down into smaller ones. He conducted experiments and thought that air was not an element but it was a mixture -
Late 1700's
During the late 1700s, many experiments and discoveries took place involving matter. First, a man named Joseph Priestly isolated oxygen and was the first person to do so Although, he did not know oxygen was an element. However, a man named Antoine Lavoisier discovered oxygen was an element not long after. Lavoisier also experimented and concluded that air was a mixture containing oxygen and other elements. Also, A man named Henry Cavidindish created Hydrogen by mixing metal with acid. -
John Dalton 1808
In 1808 a man named John Dalton had some adjustments and changes to make to Robert Boyles model. Dalton experimented and created a theory on why elements can differ from each other and differ from nonelements. His changes to Boyles theory were that all elements were made of atoms which were particles that could not be seen, each element has its own kind of atom and mass, compounds are atoms that come together to form molecules, and atoms can not be destroyed or separated during chemical changes. -
Michael Faraday 1831
in 1831, a man named Michael Faraday experimented and found that electric current can cause chemical changes in some compounds. He discovered that atoms could gain electric charges and form charged atoms called ions. Faraday made some changes to Dalton's model. These changes were, matter must contain a positive or negative charge, opposite charges were attracted to each other and the same charges were repelled. atoms come together to form molecules because there is an electrical attraction. -
J.J. Thomson 1904
In 1904, a man named J.J. Tomson experimented and discovered electrons which were light negative atoms, and also discovered heavy positive atoms which were later identified as protons. He made changes to the model and the new model was called the raisin-bun model. The changes were that atoms contained small and negative particles called electrons, the rest of the atom is a sphere of positive charge. The elections were inside this sphere meaning the remaining particles were negative or uncharged. -
Ernest Rutherford 1911
In 1911, a man named Ernest Rutherford conducted many experiments and received results that made him create a new model called the nuclear model. This model said that an atom has a small positive core called the nucleus. The nucleus deflects alpha particles and contains protons. The nucleus is also surrounded by empty space inside the atom with rapidly moving electrons.