Nothing beats a physical example of advanced scientific principles when it comes to getting a true understanding. And this is one of the best.
Typically, if you drop a basketball from any kind of height, it takes a little beating from the wind but lands basically where you’d expect it to.
But give that ball a little bit of backspin (and a whole lot of height) and you get a curveball to make a major leaguer jealous.
Why? Because, science.
Okay, so it’s specifically because of the Magnus effect, wherein the falling, spinning basketball creates areas of differeng pressures, forcing it to swerve away – not unlike an airplanes wing
A brief primer on the Magnus effect, from Wikipedia:
The Magnus effect is the commonly observed effect in which a spinning ball (or cylinder) curves away from its principal flight path. It is important in many ball sports. It affects spinning missiles, and has some engineering uses, for instance in the design of rotor ships and Flettner aeroplanes.
In terms of ball games, topspin is defined as spin about a horizontal axis perpendicular to the direction of travel, where the top surface of the ball is moving forward with the spin. Under the Magnus effect, topspin produces a downward swerve of a moving ball, greater than would be produced by gravity alone, and backspin has the opposite effect. Likewise side-spin causes swerve to either side as seen during some baseball pitches, e.g. leg break.