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460
Democritus
He believed that all matter consisted of extremely small particles that could not be divided. He thought that there were diffeerent types of atoms with different sets of properties. 460 B.C.E. -
Issac Newton
Proposed a mechanical universe with small solid masses in motion. -
John Dalton
John gathered evidence for the existence of atoms. He measured the masses of elements that combine when combines form. -
Wilhelm Roentgen
Using a CRT he observed that nearby chemicals glowed. Further experiments found very penetrating rays coming from the CRT that were not deflected by a magnetic field. He named them "X-rays". -
J.J. Thomson
He believed that if materials were were rubbed together they would attract or repel each other. He made a glass tube with metal disks on each end and a wire connecting them. he concluded that one disk had a positive charge and one disk had a negative charge. -
Hantaro Nagaoka
Nagaoka developed an early, incorrect "planetary model" of the atom. The model was based around an analogy to the explanation of the stability of the Saturn rings -
Ernest Rutherford
discoevered that uranimum emitss fasstmoving particles that have a positive charge. he did an expirement finding an uxpeccted discovery. -
Erwin Schrodinger
developed mathematical equations to describe the motion of electrons in atoms. his work lead to the electron cloud model. -
Louis de Broglie
Proposes that moving particles like electrons have some properties of waves. Within a few years, evidence is collected to support this idea. -
Niels Bohr
He made an atommade that was based on electrons. He did an expirement finding an unexpected discovery. -
Ernest Marsden
He conducted the famous Geiger-Marsden experiment called the gold foil experiment in 1909 together with Hans Geiger under Rutherford's supervision. -
Aristotle
He did not beliee there was a limit to the number of times matter could b e divided. He has a modle that shows his belief. 384 B.C.E.
