I’d give laser pointers to Neanderthals. Even if they did figure out some useful application for them (maybe hunting?) they’d run out of batteries eventually.
I’d give laser pointers to Neanderthals. Even if they did figure out some useful application for them (maybe hunting?) they’d run out of batteries eventually.
Humanity - civilised Greeks or not - didn’t have the metallurgical knowledge to be able to build locomotives and rails out of strong enough materials yet. Ancient Greece basically coincides with the Bronze age.
You’d have to not only bring (knowledge of) steam locomotive tech, but also every single bit of iron tech required to build one. You could skip the requirement for rails by opting for a steam traction engine, not a full locomotive, but those are far closer together in technological ability.
None of this factors in the propensity for steam boilers to explode, which you may or may not consider important.
There’s a reason we were still using beasts of burden (horses, oxen, etc.) for traction until the 19th century.