Amazing fact about the invention of the lighter
The cigarette lighter was invented before the match.
- Home
- What was the hardest part of inventing the wheel?
“The hardest part of inventing the wheel was the axle, because the wheel and axle had to fit together almost perfectly for the wheel to turn smoothly.”
Reference: Smithsonian Magazine
More from this shelf
When was the wheel invented?
The wheel was invented around 3500 BC in Mesopotamia, and it was first used as a potter's wheel for making pottery before anyone put it on a vehicle.
How accurately is the Great Pyramid aligned?
The Great Pyramid's sides are aligned almost exactly with true north, south, east, and west, a stunning feat of precision for ancient engineers.