Some good news for Sammy Sosa fans still whispering, "Say it ain't so." Back in 2003, Sosa was caught using a corked bat—a normal wooden bat hollowed out in the center and stuffed with lighter cork material. That embarrassing incident did happen, and it does go against baseball rules. But, according to physicists at the University of Illinois and Washington State University, a corked bat probably doesn't offer much of an advantage. Sure, Sosa technically cheated. But he didn't actually cheat in a practical sense, they say. At least, not by altering his bat.
There was some anecdotal information from players that there's something like a 'trampoline effect' when the ball bounces off a corked bat," says Nathan, one of the authors of the new study. So the researchers hollowed out a bat, stuffed it with bits of cork and fired a ball at the bat from a cannon. If anything, the ball came off the corked bat with a slower speed than off a normal bat. Less velocity means a shorter hit. Their conclusion: the trampoline effect was bogus.
But there was another way corking might work: a corked bat is a few ounces lighter than an unadulterated one, and a lighter bat means a batter can swing faster, which means he can generate more force and hit the ball farther. Right? Not quite, as it turns out.
A batter indeed can swing a lighter bat faster, but a lighter bat has less inertia. So there's a trade-off, says Lloyd Smith, an associate professor of engineering at Washington State University and a co-author on the paper. By once again firing a ball at a bat at WSU's Sports Science Laboratory, the researchers found that a heavier bat still hit the ball harder (and therefore farther) than a lighter, corked bat. "Corking will not help you hit the ball farther," says Smith.
Smithsonian: The Physics of Cheating in Baseball
Image: hung up, pt. II, a Creative Commons Attribution (2.0) image from eioua's photostream
![Perseid meteors light up the sky in August 2009 in this time-lapse image [NASA-JPL]](http://i1.wp.com/media.boingboing.net/wp-content/uploads/2016/08/geminid20091209-full.jpg?fit=600%2C338)
Mythbusters busted the “corked bat is more effective” myth in their “Baseball Special” episode, like, years ago.
It might not help your home run totals, but it will help your batting average. Sosa’s 2003 BA of .279 isn’t statistically higher than his career average, but it’s higher than his last three years. If he was already in decline in 2003, a corked bat would’ve helped cover that.
It seems strange to me that they would hold the bat still to test this theory. It would be like shooting a golf ball at a stationary golf club to test how far a driver would hit.
The benefits of a lighter bat are only explored halfway. It’s not a matter of simple energy transfer afforded by a greater velocity, but also decreased reaction times and easier control of the bat.
Waiting a fraction of a second longer to swing? Able to catch up to a blazing fastball? Easier to check swing? All – and more – are considerable advantages.
But anyone who has played baseball will tell you that bat speed is VERY important to a successful at bat. If you can get the bat around faster, you can wait longer on the pitch. That gives you the ability to get the bat on the ball more squarely. Your eyes/brain have that split-second longer to calculate the trajectory of the ball and make the bat meet it in space more directly.
Wooden bats are much harder to alter in weight without also altering length/width. (You weekend softball warriors know you can find almost any length/weight combo in aluminum). Corking allows the bat to get lighter, remain solid, and not alter the length or barrel of the bat. It IS an advantage.
This is exactly right. The corked bat was never about distance, it is about bat speed and buying extra time to allow for pitch recognition while not sacrificing less plate coverage with a shorter, lighter, legal bat.
A corked bat gives you slightly greater bat speed for more contact, but it won’t help you hit the ball farther. That’s what steroids are for.
Might as well be creationists looking for paths across the bottom of the red sea in an effort to “prove” the bible.
It doesn’t matter if corking the bat actually helped him in any way, he THOUGHT it would help him and KNEW it was cheating to, in any way, modify his bat.
Therefore, he cheated plain and simple. The fact that he cheated in a way that would make no difference (so the naysayers say) to his performance, makes no difference.
Isn’t kinetic energy linear in mass and quadratic in velocity? Losing a bit of mass to gain velocity would be a good trade.
The same equation also applies to the speed of the bat, and the energy you put into swinging it. So, assuming the energy put into swinging the bat is a constant, then even a large decrease in mass will only lead to a small increase in the actual speed of the bat. I also saw a TV show (maybe it was radio, Quirks and Quarks perhaps) about this a while back. The lighter bat is only beneficial, provided that the decreased mass actually allows you to swing it faster. So for little league baseball players, a lighter bat might help, but for guys like Sammy Sosa, they have enough strength to swing a heavy bat very fast. The weight of the bat in this case isn’t the limiting factor, but rather just how fast they can move. Basically, you should use as heavy a bat as possible such that it doesn’t decrease your swing speed. However for homerun hitters like Sosa, they have no problem swinging a standard bat at very high speeds.
*Raises hand*
But isn’t the equation for kinetic energy 0.5mv^2? Meaning that a small increase in velocity can mean a much larger increase in kinetic energy?
Also, isn’t this more of a momentum issue? If the bat’s post impact velocity were roughly the same regardless of the type of bat (and momentum beforehand was the same), wouldn’t that mean more momentum was transferred to the ball, send it farther?
I’m all for testing in a lab, but since the force the batter is using at the instant of impact and the instantaneous change in velocity pretty much determine the distance the ball will travel (assuming a constant angle of impact), I would think that locking the bat in place might give bogus results.
I believe the Mythbusters demonstrated that a corked bat does not provide any advantage; in fact it significantly reduced the effectiveness of the swing.
What they didn’t test was “belief”
If a batter using a corked bat ‘thinks’ that he can hit harder and farther, does the bat, in fact, make any difference?!
So the placebo effect is a banned substance?
Didn’t say that.
Just wondering if they can measure it!
That’s not even remotely what I suggested.
Who said anything about banning ‘belief’?!
Wait. Are they measuring bat speed by firing a ball at a *stationary* bat?
Yes, good sir, they are! I bet it’s not being held by a human hand model, either. Did they test to see what speeds a human (in the proper athletic shape) can swing a variety of bad weights (and weight distributions)?
Seriously, these tests are done at schools with sports programs, no? How hard would it be to ask the baseball team to help out with a little science? Maybe count it as some kind of extra credit to help them pass a class or two?
Heck, are they even ‘corking’ it in the right way?
It doesn’t really matter how fast the bat is moving; what matters is the relative speeds, not the movement.
If the ball is traveling at X, and the bat is traveling at Y, the ball effectively has the speed (X+Y).
By keeping the bat stationary, they can just give the ball the speed (X+Y) and not have to worry about the bat introducing any kind of random error. As long as the bat is free to react to the impact with the ball just as it would in someone’s hands, it doesn’t matter how fast the bat is traveling.
Also, to BunnyFooFoo #14 – sure, they could do that, but it would be harder to get standardized results with real human hitters. They’d either end up with poorer data or the project would take drastically longer while they wait for the hitter to hit it just right.
“It doesn’t really matter how fast the bat is moving; what matters is the relative speeds, not the movement.”
Well, yes. But the question is ‘how fast can you move bat A vs. how fast can you move bat B?’
Seems like you’d need to *move the bat* to test that.
“How fast can you move bat A” is an entirely subjective value that will depend on the individual batter and doesn’t lend itself well to testing.
You can say “how much faster for a given fixed input of energy” or “how much more energy for a given speed increase” but again, you don’t need to actually swing the bat to find those values. You can model it with a stationary bat.
Yes, but the point is how the bat performs in a game not in the test. In a game the speed of the ball is X regardless of the material of the bat. So a faster bat, Y+, will result in a higher effective speed, XY+, than the slower bat Y-.
As you say, what matters is the relative speeds. So the relative speeds are higher if the bat moves faster.
I think you’re saying that they can account for this in the test. But they didn’t, as far as I’ve seen.
Of course it’s testable. The question is whether a person can move a heavy bat faster or slower than a lighter bat. So give a person light bats and heavy bats and let them swing. With sufficient people, you could easily show how much of a speed advantage is conferred on average for every n grams of reduced weight.
Point of contact is key in hitting a home run. If you can get the bat around faster and hit the ball while it is still out in front of you and on the sweet spot of the bat you are going to hit a lot of HR’s. That is the advantage of a corked bat. I don’t think it was ever about a “trampoline effect”. Its about swinging faster and making contact earlier.
As Teller said, it’s the ‘steroids’. The corked bat is just a footnote in Sosa’s story.
This article assumes that distance is the only advantage in hitting a baseball. Sure it’s important if you’re trying to hit it out of the park, but there are lots of situations where a lighter more nimble bat would be an advantage. For instance what if your are trying to get the ball to drop into a gap for a hit or what if you are trying to bunt. What if you are trying to wear a pitcher down? You can take a lot more pitches if you can get some wood on the ball and a lighter bat may be helpful.
1) They tested firing balls at bats, but what happens if they fire bats at balls?
2) More seriously, what happens when an actual human is involved? i.e. does the perception of an unfair advantage impart an advantage even in the absence of an actual advantage?
I always thought it had something to do with the “sweet spot.” Like, maybe by hollowing out the bat, batters can use a larger bat without sacrificing speed and therefore be more likely to get solid contact. Kind of like how drivers in golf are now huge and hollow.
does the area of the sweet spot increase with the corked bat?
Another revealing example of athletes knowing something that scientists don’t know because scientists never actually played the game. The point of corking a bat isn’t to hit the ball farther or hit for power, it’s to make contact and spray weak slap hits around the field and get on base. Duane Kuiper, one of the last “Punch and Judy” style hitters for the Indians in the 1970s and 1980s was talking about using corked bats for this purpose just last weekend during the Giants broadcast.
I always figured the hollow bat with a few ounces of mercury in it would be the best way to cheat.
The slug would be at the handle on the start of the swing and move to the end at ball contact time.
A broken bat would probably bring out the hazmat suits though.
Firing balls at it would also show no advantage, although swinging it one would feel something is not quite right.
A less dense bat allows the player to swing a larger bat given the same mass, thus improving his chances of contacting the ball.
Even the best players still miss most of the time, so contact is an important consideration.
Now we know that Sosa was not just a cheater, but an inept one. That is so totally pure Chicago Cub loserdom.
If speed was that important, why not just use a legal lighter bat?
It’s not about how far or hard you can hit the ball. The trade off in weight and thus less force may provide greater mobility of the bat, in effect a short-stroke corrective capacity to delay and fine tune the swing. This may result in a higher percentage of successful at bats at the cost of greater velocity and longer hits.
Combine that with grounding and aiming techniques to keep the ball in play, and layer on the confidence-increasing “belief” factor and you may well have an advantage.
Batters don’t cheat just to hit the ball farther, but also to hit successfully more often overall.
Dear Smithsonian: Thank you for linking to the paper, or even to the copy of the American Journal of Physics.
There’s no point in debating the merits of a paper based on a second-hand description of what was in the paper. The original is available at http://www.kettering.edu/physics/drussell/bats-new/Papers/CheatingPaper.pdf. Please read that for the real story, rather than make guesses at how the tests were performed.
“You can say “how much faster for a given fixed input of energy” or “how much more energy for a given speed increase” but again, you don’t need to actually swing the bat to find those values. You can model it with a stationary bat.”
What? Test the question, not your assumptions.
It’s very important to notice what question they were trying to answer here: “Can a baseball be hit farther with a corked bat?”
As others have mentioned, and as the paper mentions, a lighter bat can be accelerated faster, giving the batter more time to see the ball before swinging. The paper contends that this may allow home runs to be hit more often, even if it doesn’t allow them to be hit as far, but doesn’t explore this possibility.
The distance of a home run has no effect on the eventual outcome of a game: a home run still scores points for everybody on base and the runner, whether it barely cleared the wall or went right out of the park. Sure, hitters who can hit farther tend to convert more fly balls into home runs, but the only concern to the player (and the team) is how many home runs they hit. If a different mechanism would allow them to hit home runs more often, even if they didn’t travel as far for the same bat/ball collision, that would still be an advantage; they have still scored additional home runs that they otherwise wouldn’t have by cheating.
Rather than jump immediately to the mechanism, the study should have begun by seeing if there is a measurable difference at all. This is less of a physics question and more of a statistics question. As BunnyFooFoo (#14) suggested, grab a bunch of ball players and let them swing at pitches with a regular bat and a corked bat. With a sufficient sample size and a proper design of experiments (blocking to reduce effects of the batter tiring, time of day, batter ability, etc.), one could do a simple comparison to determine if corked bats do offer an advantage. Only then should they have attempted to isolate what caused any observed difference. Disproving the two mechanisms that they proposed does not disprove the hypothesis that a corked bat increases a player’s home run production, or equally, that it’s an effective means of cheating.
All you have to do is watch a home run derby to see that the difficulty of hitting home runs at the major league level is not so much momentum as it is making proper contact with the ball. In a game situation, the pitcher is doing everything that can to prevent the batter from making proper contact, causing ground balls, pop ups, and fouls, instead of line drives and long fly balls. If a batter can gain an advantage that allows them to make better contact with the ball, it will allow them to hit more home runs. This is what should really be tested if one is questioning whether or not corking a bat gives a batter an unfair advantage.
Nice analysis.
The advantage of a corked bat isn’t about more home runs, though. Even the testers, God bless them, weren’t testing the essential reason ballplayers would use them. It’s not because the ball jumps better off a corked bat or that a ball travels farther off a corked bat than off a heavier bat. It doesn’t. The corked bat gives a hitter a bit more bat speed and a slightly better chance to square contact with the ball. It’s a tiny advantage, but in baseball, where a little spit on a ball or bit of sanding on the ball can benefit a pitcher’s ball movement, even the smallest advantage works. The researchers said this: “a corked bat probably doesn’t offer much of an advantage” – well, not offering “much of an advantage” is more than enough for ballplayers to try.
Come on BoingBoing, quit citing Mythbusters, you’re better than that.
It would seem that a lighter bat would make for a better impedance match with the ball, resulting in a larger portion of the bat’s energy being transferred. A test with a stationary bat uses the wrong frame of reference to see this.
Most of these points are covered in the paper’s summarizing:-
“However, there are other reasons why a batter might
choose to cork a bat. The smaller moment of inertia results
not only in a higher bat speed but most likely in a higher bat
acceleration. That is, in the parlance of baseball, the batter
can “get around quicker,†allowing the batter to wait longer
on the pitch as well as more easily adjust the swing after the
swing has already begun. So, while corking may not allow a
batter to hit the ball farther, it may well allow a batter to hit
the ball solidly more often. In a recent study of bats used in
NCAA baseball, Cross and Nathan(9) show that batters tend to
select bats with I that is less than optimum from the point of
view of maximizing v(hit), seeming to prefer frequency of
good contact to higher maximum v(hit). Although the present
study shows that corked bats do not result in longer home
runs, it makes no statement about whether home runs might
be hit more often with a corked bat.”
You guys are all missing the most important point:
The physics of baseball are more interesting than baseball itself.
corking a bat is not actually using cork.. the bat is drilled out past the center of balance.. the hole is then filled with a slurry of ground up superballs and rubber cement.. then then end of the bat is plugged with a wooden (ash) plug.. the area where the superball/rubber cement is in the sweet spot.. the diameter and depth of the hole is based on weight distribution.. the bat has to weigh the same as it did when it was inspected for play.. it’s not about the speed of the bat in the swing, it’s the speed of the baseball as it comes off the bat.. the effect is similar to using an aluminum bat.. yes aluminum bats swing faster, but the bats deform slightly mid-impact and accelerate the ball off the bat at a much higher speed..
read up on “corked” bats.. one MLB player’s bat actually had six superballs come out of the end of the bat, during play..
First take a spherical cow of zero mass . . .