https://padlet.com/artemd3/rwjb4vv3m57ymvyo Atom Timeline en-us 2023-10-03 12:26:57 UTC 2025-10-24 01:54:28 UTC hello@padlet.com artemd3 https://padlet.com/artemd3/rwjb4vv3m57ymvyo/wish/2730155166 - Made by Democritus.
- Made around 400 BCE.
- A model of a tiny, circular particle.
- No tests were done and this was not based on any scientific evidence.
- He believed these particles were indivisible and made up matter.
- He was right that tiny particles made up matter, but not about what it made up of, nor that it was indivisble.]]> 2023-10-03 12:34:20 UTC https://padlet.com/artemd3/rwjb4vv3m57ymvyo/wish/2730155166 artemd3 https://padlet.com/artemd3/rwjb4vv3m57ymvyo/wish/2730172847 - Made by John Dalton.
- Made in 1803.
- A model of a tiny, circular particle.
- He observed chemical reactions of oxygen with nitric oxide over water, and that the total pressure of a gas mixture is a combination of the subtances that make it up.
- He believed these particles were indivisible and made up matter, and that a single atom is composed of a single material. He also believed that atoms of the same element have the same size and mass, while atoms of different elements have a different size and mass.
- He was right that tiny particles made up matter and that atoms of different elements have different masses and sizes, but not about what it made up of, nor that it was indivisible.]]> 2023-10-03 12:44:45 UTC https://padlet.com/artemd3/rwjb4vv3m57ymvyo/wish/2730172847 artemd3 https://padlet.com/artemd3/rwjb4vv3m57ymvyo/wish/2730175562 - Made by JJ Thompson.
- Made in 1904.
- A model of a tiny, circular particle that is made up of smaller negatively-charged particles, called electrons, surrounded by a substance of positive charge.
- He used magnets and electric plates, producing positive and negative charge, to prove that cathode rays could be pulled up. Cathode rays are electrons. By showing that electricity could be pulled up, he proved that it had mass, and that mass was smaller than that of an atom, meaning electrons were present within atoms. Since atoms had no charge, there had to be a positive charge somewhere to counteract the negative charge of the electrons.
- He believed that atoms were thus divisible, as they were made up of smaller sub-atomic particles, with electrons being one of them.
- He was right that atoms could be divided into smaller sub-atomic particles, such as electrons, but was wrong about where they were and about what counteracted their negative charge.]]> 2023-10-03 12:46:21 UTC https://padlet.com/artemd3/rwjb4vv3m57ymvyo/wish/2730175562 artemd3 https://padlet.com/artemd3/rwjb4vv3m57ymvyo/wish/2730909029 - Made by Ernest Rutherford.
- Made in 1911.
- A model of an atoms that depicts it as a dense sub-atomic particle with a positive charge surrounded by orbits of sub-atomic particles with a negative charge, with the orbiting electrons being about the same distance away from the nucleus. Most of it is empty space.
- He fired off positively charged particles at a sheet of gold foil. Since an atom was mostly empty space, most of the particles went through the gold foil. The particles that hit the nucleus bounced back since the nucleus is positively-charged, and the same charges repel.
- He believed that the atom was made up of a dense, positively-charged nucleus, which contains most of the mass, in the center, surrounded by orbits of negatively-charged electrons that orbit that orbited it at around the same distance, with them orbiting in circular orbits.
- He was right that negatively-charged electrons orbited a positively-charged, dense nucleus that contains most of the mass, and that atoms are mostly empty space, but was wrong that they were at around the same distance and that they orbited in a fully circular pattern.]]> 2023-10-03 20:32:34 UTC https://padlet.com/artemd3/rwjb4vv3m57ymvyo/wish/2730909029 artemd3 https://padlet.com/artemd3/rwjb4vv3m57ymvyo/wish/2730913533 - Made by Niels Bohr.
- Made in 1913.
- A model of an atoms that depicts it as a dense sub-atomic particle with a positive charge surrounded by orbits of sub-atomic particles with a negative charge, with the orbiting electrons being different distances away from the nucleus. Most of it is empty space.
- He observed that hot hydrogen gives off different wave lengths of light as it's heated up. When heated up, lines of different colors are emitted, which occur from electrons jumping from 1 energy level to another. As the first law of conservation states that energy must be conserved, the energy is released as a photon.
- He believed that the negatively-charged electrons orbited a positively-charged nucleus at different distances from the nucleus, with them orbiting in circular orbits.
- He was right that negatively-charged electrons orbited a positively-charged, dense nucleus that contains most of the mass, that atoms are mostly empty space, and that the electrons orbited at varying distances, but was wrong that they orbited in a fully circular pattern.]]> 2023-10-03 20:34:32 UTC https://padlet.com/artemd3/rwjb4vv3m57ymvyo/wish/2730913533 artemd3 https://padlet.com/artemd3/rwjb4vv3m57ymvyo/wish/2730931406 - Made by Erwin Schrödinger.
- Made in 1926.
- A model of an atoms that depicts it as a dense sub-atomic particle with a positive charge surrounded by orbitals of sub-atomic particles with a negative charge, with the orbiting electrons being different distances away from the nucleus, and with them acting more like "clouds" than rings, as the marked locations are simply where electrons are most likely to be found. Most of it is empty space.
- He observed that the Bohr's Model could not predict where electrons would end up, as electrons function more like waves than spheres.
- He believed that the negatively-charged electrons orbited a positively-charged nucleus at different distances from the nucleus, with them orbiting in "clouds," as the marked locations are where electrons are most likely to be found.
- He was right that negatively-charged electrons orbited a positively-charged, dense nucleus that contains most of the mass, that atoms are mostly empty space, that the electrons orbited at varying distances, and that electrons functioned more like waves inside "clouds," with the locations being simply where they are most likely to be found, not necessarily where they will always be.]]> 2023-10-03 20:54:55 UTC https://padlet.com/artemd3/rwjb4vv3m57ymvyo/wish/2730931406