The Chemical History of a Candle (1848)

I most enjoy how thoroughly Faraday demonstrates how exactly they were able to know what they knew at the time - which gets into pretty advanced stuff. I doubt many today could so easily explain how we know certain scientific facts to be true, let alone demonstrate the chain of reasoning on their desktop.

At the time this would have been cutting edge science put into a lecture for children; his massive electromagnet would have been like having a cyclotron in a lecture hall today. At the same time, despite being something like 170 years ago, Faraday manages to stick pretty much to facts that we would still agree on today, despite all the scientific revolutions that have happened since then (like disproving the aether, understanding atoms and heat, electromagnetism, and such). Pretty much the only archaic aspects of it are the names of the chemicals he uses.

His explanation about the essence of what makes fire glow is also the best I have ever encountered.

https://www.youtube.com/watch?v=RrHnLXMTOWM&list=PL0INsTTU1k...