Tech Magazine

The Science of October: Home Runs

Posted on the 20 October 2011 by Nerdywerds @NerdyWerds

Chicks dig the long ball


  • Ball Speed
  • Trajectory
  • Wrap Up

Is there anything better than October baseball? The games all mean something, the players are at their peaks and no longer is it 100 degrees at game time. I personally look forward to the playoffs. And even though my Braves decided an 8 game lead in September wasn't enough, I'm still happy to watch the drama unfold. For those that don't share my zeal, the World Series, odd as it features two teams from America, started last night between the Texas Rangers and the St. Louis Cardinals. If anyone is interested, the Cardinals won the first game 3-2.

The Cardinals were up 2-0 until the Rangers' Mike Napoli belted a home run to tie the game up. Speaking of home runs, who doesn't love them; excluding pitchers? Chicks dig the long ball, fantasy baseball owners do to. Some people demonize the home run ball and say it's ruining the game. Those same people, coincidentally, really enjoy watching a pitcher's duel. But what is the science behind the long ball? If it were easy, everyone would be able to put one in the seats at their local stadium. In the spirit of the World Series, let's a take a look at some of the science of October.

Ball Speed

The first primary factor we're going to look at is the speed of the ball. The speed of the ball is affected by many things, but what we're going to look at today is just pitch speed and bat speed. Part of the reason most of us can't put a pitch in the stands is that we lack one or both of these things. If you're out playing with your friends, I doubt one of you is chucking 90 MPH fastballs. It may sound counter-intuitive, but the harder the pitch, the farther it can go. Think about when you were a kid and you'd throw a bouncy ball on the ground. The harder you threw it, the higher it would fly. This is because the energy you put into the ball is almost entirely transferred back upwards on impact; some energy is lost due to friction and gravity and drag. Thinking about it in these terms, it makes since a 90MPH pitch would be easier to put distance behind the 50MPH your friends may be able to throw.

Factor number two behind ball speed is the bat speed. If you look back into baseball's past, you'll notice the bats have gotten much smaller. In the early days, the prevailing wisdom was; bigger bat = more distance. Today's bats are quite light by comparison. That's why today you have people crush 500 ft home runs, unlike the old days. It's rumored Bath Ruth used a 52 ounce bat; which is ridiculously heavy as far as bats go. While a dense bat did transfer more energy back to the ball, you sacrificed a good deal of bat speed for it. Today's player swing lighter bats at amazing speeds to generate power. If a stationary object, the ground from the scenario above, returns most of the ball's energy, imagine what a bat swung at 100 MPH+ would do.

Some people may be wondering why a hanging curve ball gets hit so hard, if faster pitches mean longer homers. The increased reaction time allows for the hitter to put more into their swing. A fastball leaves very little time to gauge speed, location and other factors. But a lazy, hanging curve ball is usually 20MPH or so slower and it's right in the sweet part of the hitter's contact area. This time allows the hitter to react to more of the numerous variables involved in hitting a baseball. This time also allows the hitter to take a full, powerful swing.


The other major concern with hitting the long ball is trajectory, or the angle at which the ball leaves the bat. We've all since "mile high" pop ups and we've seen frozen rope line drives. The difference in the two is usual as simple as how the ball leaves the bat. If the bat is under the ball at all, you could send it very high but not very far. Swing over the ball a bit and you can chop the ball into the ground. If you hit it just slightly over center you may send a screaming line drive into the outfield. For maximum distance, an angle of about 30-40 degrees is sought after. Depending on how high or low the pitch is, the angle may be different.

Two forces that affect your trajectory are gravity and air resistance. The gravitational force on Earth is 9.8 meters per second squared. The longer an object is in the air, the more gravity will weigh down on it. Gravity can be overcome, to a certain degree, with speed. The faster a ball is moving, the less time it spends in air. And the less air time, the less gravity can act on it. Which is why bat speed is more important than bat girth.

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