Atomic Theory And The Study Of Matter

This information has not always been know to man though. Thankfully scientist such as J.J Thompson, Ernest Rutherford, and James Chadwick were able to perform experiments to shed more light on what the atom was made of. The electron was first found in 1897 by J.J Thompson; shortly after in 1911 the nucleus was discovered by Rutherford, leading to him later discovering the proton in 1919. Before James Chadwick discovered the neutron many scientists believed that there were additional protons in the nucleus, along with the equal number of electrons to cancel out the additional charge. Then in 1920 Rutherford thought that the protons plus the electrons made up a new particle but it was never confirmed. After a few years of study John Chadwick was able to discover the neutron through unidentified radiation experiments, one experiment in particular caught his eye Frédéric and Irène Joliot-Curie had studied unidentified radiation from beryllium as it hit a paraffin wax target. This experiment encouraged Chadwick to do some of his own experiments in 1932 which made him believe that the radiation ejected from beryllium was in fact a neutral particle about the mass of a proton. He also tried many other targets besides the paraffin wax, these included helium, nitrogen, and lithium. These experiments led Chadwick to find the the mass of the new particle was more than the proton, he also found out that the neutrons have no

Democritus of Abdera was a greek philosopher born around 460 BC, a cheerful and blissful man. He was one of the two founding fathers of the Atomic Theory. His thought process on the theory, was that matter was comprised of tiny building particles called atoms. This theory was widely questionable at this time. As people were not very well accustomed with accepting new ideas, and/or new concepts of philosophy and science. This theory was only partially correct, and as scientist of the more modern age began to look deeper into Democritus’s work, they begin to make new theories and hypothesize new ideas about the atom. Which later on, would lead to the development of the atomic theory and the most accurate description of the atom with the work of Niels Bohr.

the old view of atoms as the basic building blocks of the material world and Newtonian physics

Around 2,500 years ago, Democritus and his partner Leucippus were the first ones to develop the atomic theory in written history. Their theory proposed that every kind of matter was made up of tiny particles, which were named atomos, which means that it is indivisible. This meant that Democritus and Leucippus thought there were little particles of everything, but, the next breakthrough in atomic theory wasn’t made until the early 1800s with a french chemist by the name of Antoine Lavoisier, he was the one who came up with the idea of the law of the conservation of mass, which states that matter stays the same even when it changes shape or form. Then, James Dalton said that all matter was made up of atoms, which were indivisible, and unbreakable.

He stated that this was a mysterious force but never continued his research on it. Then in 460 B.C. there was a philosopher named Democritus. Democritus and his mentor Leocippus posed the question that if he broke bread into multiple pieces how many would breaks would it take until there was no more bread. He then was able to make a few theories being all matter was created of atoms and atoms are solid but not invisible. However, there was a man named Aristotle and many other philosophers who disagreed with Democritus and said matter was composed of four main elements. Earth, fire, air, and water. For example, a liquid was made of water and a stone was made of rock. Therefore, Democritus’s theory “ was rejected by Aristotle, one of the most influential philosophers of Ancient Greece; and the atomic theory was ignored for nearly 2,000 years.”(

Democritus made the atomic theory widely known, which stated that the universe is composed of two elements: the atoms and the void in which these atoms exist and move. (More, 1646)

One of Bohr’s most renowned accomplishments was his contribution to the atom. He discovered that the atom was a small, positively charged nucleus surrounded by electrons that travel in circular orbits around the nucleus. Most physicists run experiments in order to come

Atomic Theories 1. John Dalton John Dalton based his theory on Democritus’ findings. This was that matter could be divided and split into several smaller “units”, eventually forming a tiny particle that couldn’t be divided. This particle is an atom. Democritus and other Ancient Greeks could not support their theory or findings due to the lack of technology, equipment and understanding of atoms.

From the start of time men and women have expanded on the theory of matter and atoms. Going from Leucippus and Democritus to Ernest Rutherford the theory has expanded on influences of others experiments. It started before Jesus Christ was born. The structure of the atom and the atom has changed over a long period of time.

As technology advances so do the experiments to discover more about the atom. By 1911, Rutherford disproved Thomson's plum pudding model with his gold foil experiments. He discovered that atoms are mostly empty space and deflections are caused between a repulsive force between the positively charged nucleus and the alpha particles. James Chadwick, a co worker of Rutherford, found that there was another subatomic particle located in the nucleus called the neutron. While Rutherford’s model of the atom showed the electrons orbiting the nucleus, Bohr’s model shows the electrons traveling around the nucleus, the distance of the electrons from the nucleus are determined by energy. Then in the late 1910’s, Robert Millikin calculated the mass of a single electron by performing the oil droplet

James Dalton determined that elements exist as discrete packets of matter (Crash Course Video). Leucippus and Democritus composed the brilliant idea that all matter is composed of tiny uncuttable or “atomos” particles (Crash Course Video). There were many theories and discoveries on the knowledge of atoms in the past, some more known than others, like William Crookes (Crash Course Video and Atomic Structure Prezi).

In the science community, we have had many advancements made on the atomic atom. It began in 460 B.C. when a man named Democritus discovered that particles can continuously be broken down into smaller pieces. That idea is what started the evolution of what we know now as the modern atom, which has been clarified by Niels Bohr.

Although difficult to imagine, there existed a point in time where people lived in an environment where everything was visually there, but what it was made up of remained a thoughtless mystery. Today, this is why atomic theory is an important basis for the foundation of chemistry, physics, and various other scientific discoveries. Without atomic theory, the basic building blocks of the world would remain unclear, which would make understanding the study of science almost impossible. Atomic theory explains the idea that within the composition of matter, there exists numerous particles called atoms. This idea of the atom has been experimented and researched by numerous scientists whom built upon each others discoveries-one scientist being J.J Thomson.

The Discovery of the Atom first came from the Greeks which made a theory “The idea that all matter is made up of tiny, indivisible particles, or atoms, is believed to have originated with the Greek philosopher Leucippus of Miletus and his student Democritus of Abdera in the 5th century B.C. (The word atom comes from the Greek word atomos, which means “indivisible.”)” (InfoPlease Atomic theory)

For many years Greek philosophers were intrigued by the question of what matter consists of(Lucretius 31). In the fifth century BC, Democritus was the first philosopher to come up with a coherent atom theory. Based upon the reasoning that a stone can be split in half an infinite number of times, he hypothesized that at some point the stone would be too small for the eye to see. Democritus categorized such miniscule fragments of matter as “atomos” . Without experimental evidence, Democritus guessed that atoms of all shapes are in continual motion. Such motion affords the possibility of collisions in which atoms could attract or repel. Alterations in matter could be counted for by these collisions. Democritus’s original atomic theory had little impact on the world for many years, due to its lack of evidence, and was rejected by another renowned philosopher, Aristotle ("Ancient Atomic Theory").