Long ago, people had a lot of different ideas about how the atom worked.  Here’s an explanation of many of them. (Updated 10-13-22).  But first, a relevant comic from the always awesome xkcd.com: (thanks for letting people like me reprint your stuff!)

Historical models of the atom:

• Early atomic theory:  Ideas from ancient Greek guys, some other guys, up through the teachings of Dalton.  Added bonus:  Learn why Democritus was a weirdo.
• Early models of the atom PowerPoint:  It’s like the tutorial above, but in PowerPoint presentation and way more entertaining.
• Law of Conservation of Mass:  This is a PowerPoint that fits into the Early Atomic theory part above – kind of silly, but at least it’s short.
• Old models of the atom:  Another chapter from the same book, discussing pre-quantum atomic theory.
• Elements and properties and stuff:  A chapter from the textbook / textbook parody I never got around to publishing.  It focuses on early atomic theory, as well as the idea of chemical properties and whatnot.
• Thomson and Rutherford:  Important advances in atomic theory from a couple of guys working at the dawn of modern science.  Plus Rutherford was a total rock star.
• The Bohr atom:  Neils Bohr was awesome.  Not only did he do amazing stuff in the world of atomic theory, but he was also smart enough to know that he wasn’t right.  And, oh, by the way, his wrong model just happened to change the course of modern science.  Not too shabby for a guy whose name I misspelled above (it’s actually “Niels”).

Supplemental videos:  These videos are all over at the amazing Crash Course YouTube channel.  I didn’t make these, though I wish I did.

• Crash Course Chemistry:  The History of Atomic Chemistry – The title pretty much says it all.
• Crash Course Chemistry:  The fundamental laws.  Covers the early development of chemistry as a science.
• Why do things fade in the sun?  An explanation of how ultraviolet light interacts with the chemical bonds in various materials.
• Why can’t I put metal in the microwave?  An interesting artifact of quantum mechanics.