An example of scientific thinking moving beyond a long-standing alternative conception:
"Projectile motion, he [Galileo] reasoned, is a free fall situation with a horizontal component. At the apogee of the curve, the object starts its downward descent due to the force of gravity, but it still retains some of the horizontal impetus [sic] originally imparted to it. The path would be smooth, not discontinuous, as Aristotle had maintained; and rather than abruptly falling to earth in a sheer vertical drop, the object would describe a curve, a combination ('resultant') of the vertical and horizontal components of motion."
Morris Berman (1981). The Reenchantment of the World. Cornell University Press.
Note, today we would use the concept of momentum, not that of impetus. Although the idea that a projectile (such as a javelin) would suddenly fall straight down to earth may seen bizarre, it is still a trope in many animations (cartoons where a character runs horizontally over a cliff edge – realises, and then suddenly drops)
