History of the atom! By Caitlyn Peterson

John Dalton proposed the first atomic theory of matter in 1802 John Dalton proposed the first atomic theory of matter in 1802. His theory was all elements are composed of indivisible particles and atoms of the same element are exactly the same and atoms of different elements are different. This represents my picture because the triplets represent atoms from one element so they are exactly the same and the other little boy who is different represents an atom who is from a different element so he is different from the other element of atoms. Facts about John Dalt0n: He was born in England on Septemer 6th 1722 and died July 27, 1844. He was best known for his atomic theory but also known for his law of multiple proportions, Dalton’s law and color blindness.

Almost 100 years later after John Dalton make his theory, a scientist named J.J. Thomson discovered that atoms have electrons. Thomson’s theory was that an atom was a positively charged material with negative electrons scattered around it. The model he made was often called the “Plum Pudding” model. This picture relates to that because it uses the example of J.J. Thomson’s model being called the Plum Pudding model and this is a picture of plum pudding. Facts about J.J. Thomson: Joseph John Thomson OM PRS was an English physicist and Nobel Laureate in Physics, credited with the discovery and identification of the electron; and with the discovery of the first subatomic particle. He was born December 18th, 1856 and died August 30th, 1940.

In 1908 a scientist by the name of Ernest Rutherford discovered that atoms have a nucleus. He proposed that atoms consist of a bunch of empty space and there is a positive nucleus with negative electrons scattered around it. This represents my picture because the happy smiley face represents the positive nucleus and the blue sad faces represent negative electrons because of the negative mood they set. Facts about Ernest Rutherford: Ernest Rutherford, 1st Baron Rutherford of Nelson, OM, FRS was a New Zealand-born British physicist who came to be known as the father of nuclear physics. He was born August 30, 1871 and died on October 19th, 1937. Ernest is also known for his quotes including “If your experiment needs statistics, you ought to have done a better experiment.”

Later in 1913 a scientist by the name of Niels Bohr said that electrons move in definite orbits around the nucleus. My picture represents this because the planets act as electrons orbiting around the sun which represents the nucleus. And Niels also said that each electrons moves in a specific energy level. Just like electrons planets move in the same speed and in the same order around the sun. Facts about Niels Bohr: Niels Henrik David Bohr was a Danish physicist who made foundational contributions to understanding atomic structure and quantum theory, for which he received the Nobel Prize in Physics in 1922. He was born on October 7, 1885. And died November 16th, 1962. He also has 6 children and is also known for his quotes like “Never express yourself more clearly than you are able to think”