Sports Science: Football

The fourth Thursday in November is the perfect time to spend time with family, eat some home-cooked comfort food, and watch grown men throw around an inflated pig bladder.

That’s right, folks; the world’s first American football was actually an inflated pig bladder, hence the nickname “pigskin.” Don’t worry, modern footballs are made of leather or vulcanized rubber, but the shape of a football remains the same as it’s ever been, lending itself to an interesting discussion of physics.

My sophomore year of college at Washington University in St. Louis, my physics professor’s lecture the week of Thanksgiving featured two balls, a red rubber kickball and an American football. She asked us to predict how the balls would bounce. The spherical kickball was easy; the American football was not.

Football shape

The ovoid shape combined with the two sharp points at each end mean that the ball can bounce in just about any direction at any angle depending on its orientation as it is falling and what part of the football makes contact with the ground. That’s why every football coach I ever had drilled us on just falling on the ball instead of trying to catch it or scoop it up; it is extraordinarily difficult to predict just which way the ball will bounce! These bounces often manifest on plays when a bouncing ball is live, like a fumble, an onside kick or following a punt.

As the game evolved, so did the football itself. As you can imagine, inflating animal bladders can be inconsistent; now, the NFL football is standardized at about 11 inches long from tip to tip and a circumference of about 28 inches around the center. Those bladders could also be difficult to grip, so the modern football has a coarse, pebbled texture as well as white laces in the center.



Because of its shape, the football cuts through the air most easily when spinning around its longest axis, called a spiral. This spiral minimizes air resistance and allows the ball to move in a more predictable parabolic motion.

A common misconception is that the spiral motion allows the ball to travel farther, but this idea falls apart with basic physics. When a ball is initially thrown, there is a set quantity of total energy in the system. That set amount cannot be increased or decreased, just changed from one form to another according to the Law of Conservation of Energy. The spinning motion of a football in the air requires kinetic energy, so every Joule of kinetic energy required to keep the ball spinning is less energy dedicated to the football’s motion.

Instead, the spiral is important because of a concept called angular momentum. A spinning football behaves like a gyroscope; a ball will maintain roughly the same orientation while travelling. This makes the football’s movement from point to point easier to track and predict for a player.step0So when tossing around the ol’ pigskin Thanksgiving Day, make sure you grip the ball with the laces as you throw! What works best for me is to put my middle finger, ring finger and pinkie finger on alternating laces at the front of the ball (as pictured above).

When throwing a football, it is important to generate the force for the ball from your legs. If you are right-handed like me, stand sideways with your right leg behind you. Push off against the ground with your back leg and turn your body to throw as you do so. Bring the football backwards and then forwards over your shoulder, allowing the ball to roll off of your fingers straight. No need for any wrist twisting, as the ball should naturally move in a spiral. (See proper form below.)step1Step one: feet shoulder width apart, hands meet on the ball.step2Step two: weight on your back foot, bring the ball back, wrist out.step3

Step three: throw the ball, wrist in. Allow the ball to roll off of your fingers, but keep your wrist straight and stable. Release the ball over your shoulder. Remember, it’s not a baseball. step4Step four: follow through after the release.

Whether you’re facing the New Orleans Saints or the neighbors across the street, the principles of physics are crucial to your football team coming out on top. May the forces be with you! Happy Thanksgiving!

Come to Energy Day for a fun look into the future (and for funnel cake)!

What do funnel cakes and energy have in common?

That’s not a question most people ask. Thankfully there’s an easy answer and that’s Houston’s Energy Day this Saturday, Oct. 17 from 11 a.m. to 4 p.m.! Houston’s Energy Day is the largest free family festival focused on STEM (Science, Technology, Engineering and Math), and they also have funnel cakes for sale! It’s a huge festival down in Sam Houston Park near the Heritage Society Museum.


You can expect lots of awesome booths with fun activates and giveaways, and something fun for everybody. At the Navy booth, you can drive an underwater remotely operated vehicle (ROV) around a swimming pool. You can explore the interior of a NISSAN Leaf electric car. NASA will be on-site for cool giveaways, and both the Houston Rockets and the Houston Astros will have booths, so you can shoot some hoops and play a game of catch (though probably not at the same time).


In addition to all the fun activities, there will be an award ceremony for the winners of several contests that have been going on during the year, such as The Houston Geological Society/Houston Museum of Natural Science/Consumer Energy Alliance Art, Essay & Media Contests. Winning students and teachers will receive scholarship money and a photo holding the big check.

Art Essay and and Media Contest

Live music will play between the award ceremonies. Alongside all the festivities and funnel cakes, our museum will be there, of course! I’ll be playing with a Van de Graaf generator (shocking I know), we’ll have a cast of some dinosaur bones for you to touch, and much, much more.


So sleep in that Saturday and in the late morning, head down to Sam Houston Park for a free, fun-filled festival! See you there!

In the meantime, take a look at the rest of these other images from Energy Day in previous years.



Sports Science: Pitching!

We, as a nation, love applied physics. If anything, that’s all that sports are.

With the Houston Astros on the brink of advancing further in the 2015 Major League Baseball playoffs, take a look at this physics-based pitching preview of tonight’s American League Divisional Series Game 5 matchup between the Astros and the Kansas City Royals.

My baseball coach growing up was my friend’s dad, named Paul Mancillas. He loved to say that hitting was timing and that pitching was about disrupting that timing. He could not have been more correct. Baseball is a sport in which a fraction of a second can mean the difference between hitting a home run and swinging and missing a pitch.

The announced starter for the Astros is Collin McHugh, who was the winning pitcher in 19 games during the regular season as well as in Game 1 of this series in Kansas City. He relies on four types of pitches: a four-seam fastball, a curveball, a cutter, and a changeup.


The grip for a four-seam fastball sets two fingers across the stitching, held horizontally. The grip launches the ball into a backspin, causing greater acceleration through the air. Photo by: Jason Schaefer.

McHugh throws his fastball at approximately 90 miles per hour. This means that the ball will travel the 60 feet, 6 inches from the pitcher’s mound to home plate in approximately 458 milliseconds! Astros hitters will have even less time to react; the Royals’ expected starter Johnny Cueto throws his fastball at around 93 mph, so it will reach home plate in about 444 milliseconds!

AdairSwing (1)

An average MLB player can locate the moving baseball in about 140 milliseconds and swing his bat in approximately 150 milliseconds. So subtracting that away from the previous numbers, the batter has about 150 milliseconds to make the decision to swing or not swing at the pitch. Take too long to make the decision, and you swing too late and miss the pitch or foul it away to the opposite side.

But if a pitcher only throws fastballs at the same speed, he becomes too predictable, and a batter can easily time his swing to make good contact. That’s where the other pitches come in.


A wider, more even grip across the stitching makes a changeup move more slowly. Photo by: Jason Schaefer.

A changeup is a pitch that looks like a fastball while moving but arrives at the plate much more slowly. McHugh and Cueto each throw a changeup at around 83 mph, which travels to home plate in approximately 497 milliseconds. A batter expecting a fastball would start his swing 50 milliseconds early and, instead of hitting the ball with the fattest part of the bat, miss the pitch completely.


For a cutter or cut fastball, a slightly off-center grip causes the ball to curve right just before crossing the plate. Photo by: Jason Schaefer.

In addition to changes in speed, some pitchers rely on pitches that move horizontally or vertically. McHugh throws a cutter, or cut fastball, which has the speed of a fastball but moves horizontally right before it reaches home plate. A pitcher would hold the ball similarly to a fastball, but with a slightly off-center grip. Since a batter’s timing won’t be disrupted by a change in speed, this pitch is designed to create weaker contact with the ball. The barrel of the bat would be in one place while the ball would be in another, usually resulting in an easy-to-field ground ball.


A curveball relies on a different grip and throwing technique to achieve changes in both movement and speed. Photo by: Jason Schaefer.

Combine movement with change in speed to get the deadly curveball. A great curveball has what’s called 12-to-6 motion, meaning that it dips straight down as if going from the 12:00 position on a clock to 6:00. This occurs because of the spin of the ball. The rotation of the ball causes the air around it to rotate as well. As the air is ejected on the upper side of the ball, the ball itself moves in the opposite direction, downwards. This is Sir Isaac Newton’s Third Law of Motion in action!


Proper curveball pitching technique calls for a sideways release of the ball. Photo by: Jason Schaefer.

In addition, many pitchers throw a curveball at least 10 mph slower than their fastball; McHugh actually throws his at around 74 mph, which reaches home plate in about 557 milliseconds, about 100 milliseconds slower than his fastball! The combination of reduced speed and change in direction makes hitting a curveball challenging for batters of all kinds.

The most important feature of the baseball to pitchers are the seams, those red stitches that hold the ball together. The stitches themselves create a disturbance in the air molecules around the ball, resulting in a clean pocket for the baseball to travel through with less resistance. This allows the ball to reach greater speeds.

baseball air turbulence

Want to see if you can hit a major league fastball? All you need is a ruler and a friend! Have your friend hold the ruler in the air, and position your finger and thumb around the 0 centimeter mark. Tell your friend to drop the ruler at some point without telling you when, and try to catch the ruler between your fingers. Note the position of your fingers on the ruler; if you caught the ruler in 11 centimeters or less, you have a reaction time of about 149.8 milliseconds, which would be just fast enough to hit a 90 mph pitch! Now you just have to work on swinging the bat in 150 milliseconds, too, and maybe you could be the next big thing on the 2016 Houston Astros!

Let’s go ‘stros!

Animal Espionage: Meet the Spies, Traitors and Saboteurs of the Wild

This week, you’ll have the first chance to experience our new special exhibit, Spies, Traitors, and Saboteurs: Fear and Freedom in America – examining nine major periods in U.S. history when America faced threats from enemies within our borders. But did you know HMNS already features a few “sneaks” of our own? They’re just of the animal variety!

In our HMNS Outreach Programs, we highlight several examples of crafty creatures who have adapted creatively to their environments to prolong survival. Want to meet a few of these smart cookies? Come to our free Shell Educators’ Preview Sept. 29!

How do you become a spy? First, blend in!


Our first spy is a familiar animal to the Gulf Coast – the American alligator! One of the alligator’s strongest adaptations is its amazing camouflage. I remember fishing as a kid on the Sabine River and my dad pointing out a gator in the distance. I tried and tried, but I just couldn’t spot it! Only as we neared could I see the bumpy “dead log” silently watching us float by. Alligators are extremely well-adapted to ambush. With nostrils that stick out of the water like a snorkel and a clear inner eyelid to protect their eyes while they swim, their whole body can stay submerged as they await their prey. While too dangerous to approach in their natural habitat, our Wildlife On Wheels program Texas Wildlife often includes one of our baby alligators, still small enough to keep safely!


Several of our other spies star in our Bugs On Wheels: Amazing Arthropods program and are masters of disguise. The giant long-legged katydid, for example, is the world’s largest katydid, native to Malaysia. These awesome insects mimic leaves, and during the daylight hours they can safely remain motionless, cloaked in foliage, waiting to become active at night. They don’t only come in green though; these insects can have an endless array of shades and patterns to match the leaves of their unique habitats. And like many things that get better with age, so does their camouflage, as their back edge grows brown and tattered like an old leaf.

Traitors mean false friends.


In the natural world, traitors come in many guises, even that of seemingly innocuous plants! The pitcher plant, masquerading as a source of tasty nectar, lures in insects (sometimes even rodents) and traps them. Their victims cannot escape the waxy walls and sticky fluid inside. As their prey drowns, digestive enzymes help break down the body, allowing the plant to absorb the released nitrogen. You can meet three species of this unusual carnivore in our Cockrell Butterfly Center!


Another unique traitor native to our state is the Texas tortoise, often seen in our Wildlife On Wheels programs, though a threatened species in the state of Texas. Deceptively fierce, this desert dweller is extremely territorial, and males will fight to the death if a fellow tortoise challenges. Competitors rise up on front legs to charge, using the pronged gular scutes protruding from the shell to hook under the trespasser, attempting to flip him over. This is a deadly situation for a tortoise as all of the animal’s internal organs press down on the lungs, which causes him to suffocate if he cannot turn back over. Yikes!

The Science of Sabotage


Crushing prey with an estimated force of 60,000 Newtons, the bite of Tyrannosaurus rex would be lethal enough as it is, but some paleontologists, such as Farlow and Abler, debate that a more insidious biological superweapon could be concealed in those fearsome teeth. Fine serrations in each tooth provided strength and cutting power, but may have also allowed meat from T. rex’s last meal to linger, lending a perfect source for bacteria to feed on. Similar to that of a Komodo dragon, it is theorized that the bite of T. rex could deposit overwhelming amounts of bacteria, causing the wound to fester and become septic. Want to touch a T. rex tooth and feel the serrations? (We promise, ours are clean.) A visit from Dinosaur Discovery, part of Chevron Earth Science On Wheels, makes it possible!



Our last saboteur certainly employs a most unusual method of dispatching enemies —how about getting licked to death! The lightning whelk, a carnivorous snail, uses the sharp edge of its shell to pry apart bivalves. Once open, the whelk uses its radula (think scratchy cat tongue, but much worse!) to lick and scrape the hapless victim into smaller pieces for consumption. Fun fact: this ruthless snail is the state shell of Texas, and can often be found on gulf coast beaches. Look for a “left-handed” (sinistral) shell, shaped so it’s easier to put your left hand in. Another great place to see a whelk? In our Wildlife On Wheels: Invertebrates program, or in the Strake Hall of Malacology!

Interested in bringing these super-cool, sneaky creatures to your school or group? Send an email to or call (713) 639-4758 to book your Outreach Program today!