If you could tell the ancients one thing...

[Art Vandelay]

Steam power.

Funnily enough, the Greeks figured out steam power, they just never adapted it for practical use. One theory is that slave labor was so cheap and plentiful that steam wasn't practical for the time.

As far as I recall, the ancient Greeks didn't know how to refine steel. You can't make a decent steam engine if you don't have any materials that can handle particularly high temperatures.

[Cataclysm]

Hello, I'm trying to find a series of interviews where scientists in their field were asked what they thought would be the most important thing for ancient peoples to know. I think one of them said that matter is made of atoms, other than that I don't remember anything about it.

If you have no idea what I'm talking about, feel free to supply your own answer.

Mine would be: "Disease is caused by tiny creatures that are too small to see. You can avoid letting them into your body by washing yourself regularly, boiling water and cooking food, avoiding contact with sick people and their waste, and cleaning wounds with alcohol."

I would tell them to get filthy as possible to build immunity.

When they're young. The elderly should stay as clean as possible.

Good point. Also, I'd tell Native Americans to domesticate animals.

[Meshakhad]

Gonna go with the scientific method.

[R. U. Sirius]

I would tell them about meditation and non-violent problem solving.

...I'd hope you'd also teach them the necessity of self-defense when necessary, because otherwise, they're gonna get curbstomped the moment the nearest tribe decides a violent takeover would be fun

Of course; I'm not an idiot. But there's a big difference between self-defense and endless cycles of blood feuds.

[Fpqxz]

It would depend on which ancient cultures you are talking about, and what geographical location they are in.

[Osama bin Bambi]

I'd probably tell them how the scientific method and logical argumentation works.

[Cataclysm]

Newton's laws

[Zygarde]

I guess I would tell them that for the good of future generations don't hunt every animal you see into extinction.

[Star Cluster]

The answer to any mystery you don't understand isn't "God did it."

[Art Vandelay]

Assuming they actually do what I say, I'd tell them to gather as much wealth as they possibly can, ensure it's all in the form of cash by around 2008-2009 and then promptly dump the lot of it into my bank account.

Failing that, I'd just teach them a few songs of my choice and hope they see it as some sort of religious revelation. Just so archaeologists can discover some ancient civilisation whose holy men would sing "I am a dwarf and I'm digging a hole. Diggy diggy hole, I'm digging a hole" in praise of their gods.

[Lt. Fred]

Ignore Aristotle.

[Igor]

"Invest in laserdiscs" xD, that needs to have been more of a thing.

In all seriousness I'd probably go back to the early 20th century and give them semi-modern computer technology, see where we'd end up today if we could do then what we can do now, say, introduce a relatively modern computer in 1920, they get the internet by the 50s... where would it go from there?

[QueenofHearts]

Trust me, Enron is a legit investment.

[RavynousHunter]

"This is how lightning works.  Its not the work of gods, just physics."

[Witchyjoshy]

Listen to Tesla, invest in his stuff.