Thomson's plum pudding model viewed the atom as a massive blob of positive charge dotted with negative charges. A plum pudding was a Christmas cake studded with raisins "plums". So think of the model as a spherical Christmas cake. Some scattered in various directions, and a few were even deflected back towards the source.
He argued that the plum pudding model was incorrect. Rutherford proposed that the atom is mostly empty space. The electrons revolve in circular orbits about a massive positive charge at the centre.
The small positive nucleus would deflect the few particles that came close. The nuclear model replaced the plum pudding model. The scientists expected the alpha particles to pass straight through the foil, but something else also happened. Some of the alpha particles emerged from the foil at different angles, and some even came straight back. The scientists realised that the positively charged alpha particles were being repelled and deflected by a tiny concentration of positive charge in the centre of the atom the nucleus.
He submitted his ideas to the edition of the Philosophical Magazine , where Thomson wrote:. Join the ZME newsletter for amazing science news, features, and exclusive scoops. More than 40, subscribers can't be wrong. This theory was embraced by physicists, who started devising experiments to learn even more about atoms, based on this configuration.
Rutherford immediately suspected a planetary model of the atom, where the nucleus is like a star, and the electrons orbit around it like planets. This means it would lose energy in the process, spiraling closer to the nucleus, and collapsing on the atom in picoseconds. This model is a disaster because it would suggest that all atoms are unstable, which is clearly not the case.
According to Both, the electron is able to revolve in certain stable orbits around the nucleus without radiating any energy, contrary to what classical electromagnetism suggests. The idea is that if we want to truly learn something, and not just memorize it, it helps to build a process.
If we go through the stages of how physicists first learned about the atoms, what theories they had, and how these theories were proven or disproven, we gain a much better understanding. Rest assured: as science and technology progress, no doubt some of the models we use today will turn out to be flawed, and people will still learn about them. Science is rarely about finding an ultimate, finite truth — instead, science is about adding more and more layers of understanding and building approximate models.
Andrei's background is in geophysics, and he's been fascinated by it ever since he was a child. Feeling that there is a gap between scientists and the general audience, he started ZME Science -- and the results are what you see today. Home Science Chemistry. The Plum Pudding Model: how a flawed idea was instrumental in our understanding of the atom The tale of how an old British cake influenced leading physicists.
January 22, Reading Time: 9 mins read. Get more science news like this Tags: atom Cake plum pudding model.
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