All of the world’s best scientists didn’t know that projectiles moved on parabolic paths until Galileo’s experiments on inclined planes in the 17th century. 21st century schoolchildren who haven’t been taught about it likely don’t either.

Here’s Tartaglia’s picture from the 16th century, drawn from his experimental research: https://www.maa.org/sites/default/files/images/upload_librar...

And here’s another similar diagram tossed up by image search: http://ej.iop.org/images/0143-0807/33/1/149/Full/ejp405251f1...

If you look for even earlier diagrams they show a projectile moving in a straight line for some distance and then suddenly dropping straight down.

Cf. https://en.wikipedia.org/wiki/Aristotelian_physics