Dear Splinters Enquirer,
If you ask me, it's these kids today. They don't know how to play the way we used to. Why, back in my day ... and so on.
But in this case, there really is quite a bit of truth to the notion that things were different a few years ago. Now, watch any major league baseball game, and you'll see a few broken bats due to a marvelous confluence of knowledgeable craftsmanship, veterans' know-how, rookie mistakes, ecosystem biology and physics.
Baseball bat basics
Many players today grow up and spend their entire premajor league careers playing with metal bats. So when players get to the major leagues, they are not familiar with the care and use of a wooden bat.
The problem simply stated is that wood, and thereby a bat made from wood, is anisotropic. Aniso what? You heard me, or read me. Unlike a typical chunk of metal or Jell-O, wood does not have the same strength or structural properties, when pulled or pushed in different directions. Wood has fibers, made of lignin (like ligament) that run from top to bottom, treewise.
So it is with a bat; a bat has those same wood fibers running from knob to heavy end. From the end, a bat is a circle, and it's cut from within the circular cross section of a tree. So when you examine a bat's end, you'll see that it has gently curving layers. The natural bond between these layers is what often gives way when a batter gets "sawed off." That's when a pitcher throws the ball in such a way that the batter hits it with a thin part of the bat handle, and it breaks (as though it were sawed off).
As you might imagine, a bat is cut out of a long rectangular block of wood, which in turn was cut from a big round tree. The bat is cut by spinning it on a lathe, while gently but firmly bringing a very strong, sharp cutting tool to the surface. After the bat is shaped just so, a craftsman carefully judges the best orientation of the bat to be strong against a ball, and marks the bat with a label. This marking is traditionally burned into the wood like a cattle brand, so it's often called "branding" the bat.
How to hold a bat
So what would that orientation be? Basically stated, it's edge-on. Imagine a paperback book. Better yet, pick one up, and slap it into your palm or onto a tabletop. Which way is it stiffest? The pages present themselves flexibly, when bent in the direction you turn pages. But, they get stiff when you hit 'em along their edges. So it is with a wooden bat. The craftsman batmaker places the brand so it's parallel to the wood grain layers underneath it.
Now imagine yourself at home plate ready to make your mark in baseball record books. You want to orient the bat so that the layers are swung parallel to the ground. You want the brand facing up. You want to, in a word, brand the bat, before you swing.
If you don't brand your bat, you'll be bending and banging the bat in an unfavorable orientation. The chances of it breaking are much, much higher. It can have less than half its potential strength this way. Observe modern players; many of them don't brand their bats. They don't have the brand facing the sky as the bat crosses the plane of the plate, so their bats are more likely to break. It's a habit many players who grew up with metal bats need to work on changing.
Bats aren't what they used to be
There are a couple of other factors at work as well. For starters, we have the world's burgeoning population. Humans invented baseball around the same time we came across ways to make machines do work for us. With machines, our farming became more efficient. We could feed more and more of us. Our needs for forest resources became greater. We cut down a lot of trees.
When trees are replanted, in general, they're not as big and robust as the so-called first growth. The soil's nutrients haven't been adequately replenished. The trees are growing without the benefit of up-and-running ecosystems. They just don't grow in the same way. So, it is possible that modern bats are made of material that's not as strong, or at least, not as well suited to batmaking as they were years ago. Second growth may be second-rate.
Modern players have discovered that a fast bat is more effective than a heavy one at slamming baseballs a long way. This is a remarkable and elegant feature of the universe. When we hit baseballs we're transferring momentum, which is the combination of how massive something is and how fast you've managed to get it moving.
In order to get the bat moving, you have to apply force. That force, over the course of the swing, gives the bat energy. For a given batter, the swing is about the same length no matter how heavy the bat. The faster he or she can pull the bat over the course of its swing, the more energy will be available to the ball. Take a moment and take this in. The energy that the bat gets is determined by its momentum combined with its speed again. Energy goes with the velocity times itself -- velocity squared.
So lighter bats can give the ball more energy. Because of this, players are choosing lighter and lighter bats, which means they're also thinner and thinner. This, too, makes for more broken sticks.
Finally, and this is subtle: Most players have stopped batting with their bare hands. The weather is quite cool at many spring training camps. So, players wear gloves to keep their hands from getting rattled, especially when they don't hit the ball squarely. Once you get a feel for a bat with gloves on, you might just keep the gloves on for every at bat all summer.
So, players have selected bat handles that are thinner by a couple of thicknesses of leather. A millimeter or two, or a sixteenth of an inch or so may not sound like much. But, it can render a bat handle 10 percent smaller. The strength of a cylinder like a bat handle goes not as its diameter, and not as its diameter squared. Instead, when a rod is bent, its stiffness depends on its diameter squared times its diameter squared. It goes as the fourth power of the diameter. So a 10 percent reduction can mean a 35 percent reduction in strength. That's a lot. Yikes. No wonder we're seeing all this kindling in the infield.
Perhaps as more bats break, players will want to take steps to keep them intact. Bigger handles, better wood, and branding would all help.
Meanwhile, it should be possible to engineer a material that feels like wood and performs like wood. As easy as it might be for car dashboards, it has proven a bit of a problem for the marketplace. Stay tuned though; engineers are working hard on new anisotropic fiber materials all the time. Perhaps soon, the crack of the bat will be a result of well-designed stuff, and more of our trees will be left standing. Play ball!