![atomic theory timeline atomic theory timeline](http://s3.amazonaws.com/s3.timetoast.com/public/uploads/photos/2653268/Timeline.png)
In 1908, the English physicist Ernest Rutherford performed an experiment using positively charged particles fired at gold foil. Chocolate Chip CookieĦ Rutherford 1908 Information Atomic Model Analogy Cherry with a Pit His theory was that atoms are made from a positively charged substance with negatively charged electrons scattered about, like raisins in a pudding or chocolate chips in a cookie. He proposed a model of the atom that is sometimes called the “Plum Pudding” model. He discovered the presence of a negative particle in the atom – the electron. Thomson provided the first hint that an atom is made of even smaller particles. In 1897, the English scientist named J.J. Billiard ballĥ Thomson 1897 Information Atomic Model Analogy Chocolate Chip Cookie All atoms of a given element are exactly alike and atoms of different elements are different. Atoms are too small to see, “uncuttable,” and indestructible. Dalton theorized that all matter is made of atoms. He formulated the first atomic theory since the “death of chemistry” that occurred during the prior 2000 years. In the early 1800s, the English Chemist John Dalton performed a number of experiments that eventually led to the acceptance of the idea of atoms. Death to the field of Chemistry for 2000 years!Ĥ Dalton Dalton 1803 Information Atomic Model Analogy Billiard ball He also believed that matter had just four properties: hot, cold, dry and wet. to Early 1800’s Information Atomic “Model” “Analogy” In ancient Greece, the popular philosopher Aristotle declared that all matter was made of only four elements: fire, air, water and earth. Legosģ Death to the field of Chemistry for 2000 years!Īristotle 300 B.C. He named the smallest piece of matter “atomos,” meaning “not to be cut.” To Democritus, atoms were small, hard particles that were all made of the same material, but were formed into different shapes and sizes. He believed that the smallest possible piece of matter was indivisible. He questioned whether matter could be divided into smaller and smaller pieces forever until eventually the smallest possible piece would be obtained. Information Atomic Model Analogy Legosĭemocritus, a philosopher in ancient Greece, began the search for a description of matter. The atomic theory has changed over time as new technologies have become available.Ģ Democritus 400 B.C. Scientific knowledge builds on past research and experimentation. Presentation on theme: "Atomic Theory Timeline"- Presentation transcript: