The invention of the wheel

The important insight was connecting an axle, which required considerable technical precision.

Apparently, "there are linguistic reasons to believe the wheel originated with the Tripolye people of modern-day Ukraine. That is, the words associated with wheels and wagons derive from the language of that culture."

http://www.scientificamerican.com/article.cfm?id=why-it-took-so-long-to-inv

Intriguing article. It is surprising to me that the evidence points to toy models coming before wheels and axles were used at a practical size.

ETA
So maybe some kids were playing with toys and made wheels for them. And this toy idea happened in multiple places. But in one place, one adult envisioned something practical in the kids' toys and worked to make that kid idea useful at a larger size?

I'm always learning new stuff, here. If I'd thought of it, I think I'd have assumed that wheeled vehicles just automatically popped up wherever there were some domesticated animals to put in front of them and some flattish land.

And on the eighth day, after resting from his labors for a day, He made the wheel, and the chair, and taught the man, Adam, the secrets and joys of fire.

I like the comments below the article and the discussion about how the authors 'have used a very narrow definition of what constitutes a wheel'. Certainly pulleys and pottery wheels are, um... wheels.

Exactly, and wheels on toys are wheels that have solved the conceptual problems the author mentioned, how to attach them to a stable platform. Wouldn't a modern engineer call them scale models?

What was missing was an economic opportunity to exploit them. Yes South American civilizations moved grain but, being located in the Andes Mountain Range, their best roads were still difficult for pack animals. Pulling a wagon or cart along them would not have increased the efficiency of the animals.

The real problem with using wheeled vehicles is, for four wheeled vehicles, to develop a way for the front wheels to pivot at a point between them to allow the wagon to turn a corner. The earliest four wheeled vehicles had to be dragged around any turn. So the earliest wheeled vehicles were single axle chariots.

One of the first real problems of using wheeled vehicles, applicable also to two wheeled vehicles, is the prevention of fire where the axle turns in the box.

Robert

I heard (from a different source, apparently) that the original wheel was a square, and rather than take into consideration the comments of those who used it, the wheel-makers remade it as a triangle to eliminate one bump.

Then they eliminated one more bump and that's how the sled was invented.