The Physics Behind Curveballs

Not everyone is made equally when it comes to baseball. Some people are pretty good at it, and some people (like me) are shockingly bad. And then there are people like Luis Arraez of the Minnesota Twins, who displayed such control of the ball in their game against the White Sox that he hit an incredible curveball, earning his team a home run. It's not magic that made this possible, it's physics.

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As you can see in the GIF above, after Arraez hits the ball, it heads in one direction for a good 12 feet or so, until it changes direction quite suddenly. There's no way this was a mistake: it was a clever, calculated move, and it worked. So what on earth happened?

Via Dead Spin
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What you saw the ball doing is called a curveball. This can happen when the ball is hit by the pitcher or hit by the batter, and it depends entirely on physics. The reason a curveball curves is due to a force called 'lift' (which is what makes airplanes fly). Once the ball has been thrown, or hit, it starts to spin. Because it is spinning, it experiences the Magnus Effect. It is this force that is responsible for the curve of the ball.

Via Giphy
The most important part of a curveball is the spin of the ball, which makes it easier for air to pass on one side of the ball instead of the other side. This is possible because on a microscopic level, the surface of baseballs aren't smooth. The roughness allows the ball to push the surrounding air with it's spin, passing the air on one side faster than the other side. This reduces the air pressure on the fast side of the ball, and the ball is dragged to the side with lower air pressure.

Via Science Niblets
So there you have it! If you want to make the opposing team scramble for the ball like Luis Arraez did, all you need to do is apply a bit of physics to your hit. Easy as pi.

Via Giphy