jan 1, 1904 - Joseph John Thomson

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Joseph John Thomson, also called J.J. Thomson, was a British scientist born in 1856 (Kozlowski, 2020). He revolutionised the view of atomic structure with the discovery of the electron (Kozlowski, 2020).

Thomson studied the electrical discharge of cathode ray tubes, invented by William Crookes and others around 1869-175, conducted various experiments with them (Helmenstine, 2020). He deflected them off electrically charged plates and magnets to observe their interactions with electric and magnetic fields (Helmenstine, 2020). This enabled him to determine that the cathode rays were negatively charged, and he used the angle at which they deflected to calculate their mass to be much smaller than the atom (Kozlwoski, 2020).

The results were the same across his experiments, regardless of which gas he used to create the cathode rays. This led him to believe that electrons are universal and are present in all atoms (Kozlowski, 2020).

From his discovery of the electron, he proposed his own model of the atom: the plum pudding model. This model viewed atoms as positively charged masses with negatively charged electrons embedded in them to balance the charges (Kozlowski, 2020).

Through Thomson, the world had seen a glimpse of subatomic particles, and his work shone a new light onto atomic structure.

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