Small: The Atomic Theory

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How big is ‘small’? Is it a grain of sand, a speck of dirt, a strand of hair, a drop of water? Is it the size of what humans can see, with our own two eyes? Is ‘small’ bigger than that? Or is it much, much less? For years, people tried to discover the definition of small for the scientific world. Does ‘small’ act the same way as ‘big’? Can the movements of ‘small’ be described and categorized? All of these questions were analyzed over and over by scientist for hundreds of years, to form what is called the atomic theory. Today the atomic theory states that all matter is comprised of tiny particles called atoms, that atoms of the same element are all identical in mass and properties and cannot be created or destroyed, and that compounds are …show more content…
Scientists began trying to form a further and deeper understanding of the intricate structure of the atom and it’s complex properties. The first observations suggesting smaller particles within a single atom where extracted by using a gas discharge tube. This contraption uses supercharged (+/-) metal plates that pull apart the atoms of a specific gas sample. The positive particles moved towards the negative collectors and vice versa. No matter what gas sample was tested in the tube, the negative particles always had the same characteristics. The positive ions behavior would change depending on the sample of gas in the apparatus. This demonstrated that atoms contain smaller particles with positive and negative charges. JJ Thomson (1856-1940), taking and perfecting this knowledge with his experiment, is recognized with calculating the ratio of electron charge to mass and the first model of atomic structure to account for the positive and negative sub-particles. Thomson measured the amount of magnetic force needed to exactly counterbalance the deflection of a strong beam of electrons projected between charged plates. He used this to find the ratio of charge to mass of an electron: -1.76x1011 C/kg. Thomson re-concluded the fact that atoms are divisible and explained their overall neutral charge by proposing that the electrons were embedded in a sea …show more content…
Under Rutherford, he devised a means of measuring gamma radiation, and proceeded to measure the absorption of gamma rays by various gases and liquids. He worked heavily with atomic numbers and with forces inside the nucleus. Chadwick continued his research well into the second world war, and became deeply involved in the atomic bomb. He was reached out to by the government asking for his opinion on the possibility of an atomic weapon and responded skeptically. However, this made him curious and together with Rudolf Peierls discovered the power of gaseous uranium-235. After even further research, Chadwick and associates determined that less than 1kg of uranium-235 could have as much affect as 1 ton of dynamite. The report that compiled all this information was presented to Franklin Roosevelt and pushed the US to pour millions into the Manhattan Project. Chadwick was quoted saying, “I wish I could tell you the bomb is not going to work, but I am 90 percent sure that it will.” reflecting his moral opinion of the atomic

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