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!

Ecoteens build model artifacts for Block Party, opening soon

by John Pederson and Marce Stayer

The Aztecs, one of the greatest Mesoamerican cultures, had all the hallmarks of an advanced civilization. One of their most famous structures, the Templo Mayor, graces the Aztec portion of the John P. McGovern Hall of the Americas. It is a fantastic temple complex, the main religious center of the Aztec capital, and is a feat of architectural genius.

Aztec pyramid complete!

A true-color version of a model Templo Mayor will grace the demonstration shelves of Block Party, HMNS’s new interactive exhibit. And it was built by Moran Ecoteens

The Houston Museum of Natural Science is building a new exhibit called Block Party inspired by the materials used in the construction industry. Curated models of exhibit hall pieces (and visitor-submitted ones) will be on display at the new exhibit. So when the Moran Ecoteens were presented the task of making some of them, an Aztec temple was a popular choice. An image of a temple as inspiration was printed out, and we were ready to build…or so we thought.

John and Connor constructing the pyramid

John and Connor solve building support problems while constructing the pyramid.

Turns out, not all toy building blocks are useful for this purpose. And after we grabbed enough bricks to make the first two exterior layers of the temple (e.g. the Step Pyramid at Saqqara has six “layers”), it was all we could do to prevent the third level from collapsing under its own weight. (To save bricks, we had only built the outside of each layer, leaving the inside hollow.) Eventually, over the course of several days, I worked out a system of struts, columns, and crossties to hold the layers together; the hollow inside was now full of scaffolding. This allowed us to construct a model with accurate dimensions, while reflecting realistic building techniques. The Aztec temple walls were stone encased in painted plaster; our temple reflects this with rigid supports enclosed by a decorative outside shell.

John P. and Aztec pyramid 2

John stands with his model Aztec pyramid built from plastic blocks.

Our multicolored model is the prototype of a future model of the Templo Mayor. The new one will be made of realistically-colored bricks and have a simpler brick-laying scheme, more similar to the Aztec inspiration. Hopefully, those who see it will appreciate both the spirit of the Aztec culture and the engineering genius that defines the monument.


Cream of the Science Crop: Becoming an Ecoteen

You might be wondering how you can get involved doing cool projects for the museum like the Block Party demos. Here’s some information and application advice directly from Marce Stayer, director of the Ecoteen program.

The Moran Ecoteens are the museum’s teen volunteer program, open to teens ages 14 to 17 and rising ninth grade through rising 11th grade. Teens may apply beginning in December by sending their contact information to Stayer. You’ll be asked to provide your name, street address, a phone number and an email where they can be reached. The first week in January, information packets and applications are sent out to all who apply. Applicants will be asked to include a résumé, a letter of recommendation from a current teacher and an essay on the teen’s favorite area of science. The essay can be related to artifacts in our permanent exhibit halls, but it doesn’t have to be. If you’re interested, work hard to write well! We always receive more applications than slots available for this very competitive program.

Completed applications are due Feb. 28. As applications are turned in, teens are invited to schedule an interview. The process must be complete by the second week in March.

Dimetrodon skull and skull

Ecoteens built this model Dimetrodon skull for Block Party, as well.

Selected teens are required to volunteer for one two-week session during the summer. Xplorations summer camp runs on a two-week-on, one-week-off schedule and Ecoteens may choose from these two-week sessions. A new Ecoteen is required to volunteer in the classroom as his or her first assignment. At the end of each week, the teen’s performance is graded by his teacher and turned in to me. If his performance is satisfactory, the Ecoteen may volunteer for additional weeks and have opportunities to work in other areas.

In addition to classroom assignments, Ecoteens are trained to work the touch carts and permanent halls throughout the museum and some are allowed to work in the Special Exhibit halls. They are trained by master docents from the adult volunteer guild for these assignments. They also give science demonstrations to the classes during camp sessions. We have movable demos in Chemistry and Physics, we have a catapult and trebuchet demo, and this past summer, one of the Ecoteens wrote a biology demo called “Microscope Safari” and another created a Morse code demonstration.

Lastly, the Ecoteens help the Youth Education department by working on various crafts that are used during camp — wands and hats for Wizard Academy, belts for Star Warriors Academy, plaster footprints, teeth and claws for the various paleo classes, giant T. rex footprint cut-outs, complete skeletons made out of paper bones, and whatever the classes need. We also write and perform the CSI crime scene on Fridays and put on the Wizard Academy Triwizard tournament. In short, we jump in wherever we are needed!

If this sounds like something you’re interested in, now’s the time to ask for an application so you can get started and be competitive. Best of luck!

Editor’s note: John Pederson is a Moran Ecoteen Coordinator and high school student. Marce Stayer’s official title is Director of the Moran Ecoteen Volunteer Center.

Zahi Hawass delivers inspiring speech at HMNS Excellence in Science Luncheon

He’s met President Barack Obama, Shia LaBeouf, Kurt Russell, Goldie Hawn, Megan Fox and Susan Sarandon. He looked King Tutankhamun in the face, burrowed under the Sphinx and claims to have found the temple of Alexander the Great and the mummy of Hatshepsut. With a lifetime of distinguished discoveries and achievements to draw from, famed archaeologist Dr. Zahi Hawass shared his adventures with the students and educators present at the 2015 Houston Museum of Natural Science Excellence in Science Awards Luncheon.


Thursday, Oct. 22, Hawass delivered an astounding keynote speech to 182 attendees, including HMNS President Joel A. Bartsch and Ernie D. Cockrell of the Cockrell Foundation. The pair awarded Eleanor S. Frensley Student Scholarships to Rolando Marquez and Philip Tan and presented Mycael Parks and Dr. Thomas Heilman with Wilhelmina C. Robertson Teacher Awards.

In his speech, Hawass inspired both adults and students in the audience with his experience growing up from humble beginnings and coming late to the game.

“I was not always a good student,” Hawass admitted. “I wanted to be a lawyer so I could make money. Then I thought, I couldn’t stand this.”

Before he was 20 years old, Hawass pursued careers as a lawyer, a diplomat, and in archaeology. He hated being out in the desert, he said, because of the high temperatures and the punishing sun. But when he was sent on an excavation and asked to sit down in a tomb to brush dust from a statue of Aphrodite, he found his love of archaeology.


Now, Hawass lives by one word: passion. “You can like anything,” he said. “You can love anything. But if you give your passion to anything, you make it great.”

In a riveting slideshow of shots from Egypt, Hawass shared new discoveries about the location of Nefertiti, the use of contemporary imaging software to peer inside the great pyramids, working with actors and meeting the President of the United States, and excavation projects in the Valley of the Kings.

Hurricane Patricia breaks records and threatens Mexico and Texas

In only 24 hours, the strongest hurricane on record was born. Hurricane Patricia, which dumped devastating rains over Central Mexico and blasted 200 mile-per-hour sustained winds Friday evening and Saturday morning, had a central pressure two millibars lower than Hurricane Wilma, the previous record holder. Wilma struck the Yucatan Peninsula and moved on to the Texas coast during the 2005 Atlantic hurricane season in the same oceanic conditions that brought Rita and Katrina. The best that Texas meteorologists could say of Patricia is thank goodness it was in the Pacific, and made landfall in a relatively rural area.


As the worst of Patricia struck an area near Cuixmala and moved inland over the weekend, the storm was expected to present catastrophic conditions to a major swath of the Pacific Mexican coast. Communities near the ocean and just inland were susceptible to a tremendous flash flooding threat from a projected downpour of 10 to 12 inches of rain, widespread power outages and downed trees. Rainfall in the mountains was expected to collect in valleys and rush downhill to low-lying areas, swelling waterways further.

weatherHowever, CNN reports that Mexico dodged a bullet. Tourists and poor communities were evacuated well ahead of the storm, and in spite of the threat of devastation, there were no reported deaths. When Patricia made landfall, the storm rapidly weakened as it crossed the Sierra Madre, and meteorologists downgraded its status to a low pressure system with wind speeds averaging 35 miles per hour. Storms this strong usually bring down communication infrastructure that must be rebuilt, said David Paul, KHOU-11 Chief Meteorologist.

rainfall totals

Source: The Weather Channel

Texas didn’t see hurricane conditions, but residents throughout the state received heavy rainfall. As the storm crossed the mountains and its energy was pushed further up into the atmosphere, it carried with it weekend rainfall totals averaging 12 inches for the state. West and Central Texas endured flooding conditions Friday morning and areas from Victoria to San Antonio and further north into Austin, Waco and Dallas witnessed widespread heavy rainfall, all caused by the disturbance of Patricia’s forward march.


By the time the storm reached the U.S., its power was significantly weakened. For Houston, Patricia meant flash flooding conditions. The city saw more than seven inches of rain over the rest of the weekend. Communities along the coast experienced strong, gale-force winds and an increase in coastal flooding threat.

“The major threats are flooding,” Paul said. “Because it will still have a tremendous amount of vorticity or twist, there will be a tornado threat that will last through Sunday and into early Monday.”

With a storm this powerful, the best advice is to get out of the way. Upwards of 50,000 people in Mexico evacuated, and still more were affected by dangerous conditions.

Scientifically speaking, Patricia was “a beauty,” Paul said. It had a strong, well-defined eyewall and formed in ideal conditions.


“We’re in an El Niño year, and it’s the strongest ever measured,” Paul said. “The sea surface temperatures are above normal, so the storm has plenty of warm water (to fuel it). What has allowed Patricia to become so strong is a lack of wind shear. The upper-level winds were perfect for tropical storm development. No wind shear allows it to ‘bomb out.’ That’s a term we use to mean strengthening rapidly. It went from 65 mile-an-hour winds to a 160-mile-an-hour Category 5 hurricane in 24 hours!”

Imagine poking your head out of an Indy 500 race car shooting down the track. That’s what it’s like to feel sustained winds of 200 mph. Structures in its path, even those on foundations are all likely to have been flattened.


Comparing historical data from Galveston, meteorologists believe the hurricane that laid ruin to the Texas coast in 1900 was probably a Category 4. Winds reached between 140 and 145 miles an hour in that storm, and Hurricane Katrina topped out at 175 mph. At 200 mph, Patricia seems to defy the five-category Saffir—Simpson Scale with its outstanding wind speed, and even Paul admits this storm may require its own category, but that doesn’t mean it’s the strongest that could ever have occurred.

 “We don’t have a special section to put it in, but we’ve only been measuring these hurricanes since about the 1970s,” Paul said. “There may have been stronger ones.”

That said, there are some other distinctions to make. The high winds only occur at the eyewall, diminishing further out. And Paul hesitated to use the storm’s historical strength as evidence of any significant global trends.

“I don’t see that. El Niño may be one of the factors, the warming of the Pacific waters a little above normal,” Paul said. “I just see this as a storm that got in the right place at the right time with the upper-level winds.”


So should Americans be worried about hurricanes of Patricia’s magnitude forming in the Atlantic this season? Paul had an answer for that, too.

“We’re nearing the end of the season, but it doesn’t end until November 31. If you live on the coast, that’s the price. The price you pay is to be prepared for hurricanes to come along every once in a while.”

Residents of Texas and Mexico alike are urged to monitor the weather all weekend long using whatever resources are available. KHOU-11 will keep an eye on the storm 24/7 and will provide updates on its progress on Facebook, Twitter and on the Web.

Do not drive in flash flood conditions. If you must, take extreme caution. Remember to turn around, don’t drown. Get to higher ground.

When the storm has passed, learn more about how the weather is broadcast at the Houston Museum of Natural Science at the KHOU-11 Do the Weather with Chita Johnson exhibit.

Stay safe!