Every four years, the men’s World Cup delivers some certainties. The pitch dimensions are tightly regulated, offside is signaled with a flag, and referees end the match with a blast of a whistle. But one key piece of equipment is changed on purpose: the ball.

Adidas, which has supplied World Cup soccer balls since 1970, introduces a new match ball for every tournament, and with that comes fresh aerodynamic calculations for players. How will it fly through the air, weave and dip?

For the past 20 years, my engineering colleagues in Japan and England and I have put the new balls through their paces, investigating soccer ball aerodynamics. Our work begins by putting balls in wind tunnels to measure drag, side and lift forces. We use the measurements from these tests in trajectory simulations that tell us how the ball will behave in a real-game setting.

That may all sound a little academic, and we do produce an academic paper on our findings. But what our data indicates could mean the difference between a goal or a miss for strikers, a save or a blunder for goalkeepers, and jubilation or heartache for fans.

At the World Cup, the ball is the most important piece of equipment in the biggest tournament of the world’s most popular sport.

This year’s ball, the Trionda, is especially interesting. When FIFA and Adidas unveiled it in fall 2025, the first thing many people noticed was the color and the paneling.

The ball’s red, blue and green graphics correspond to the three host countries, with maple leaf, star and eagle motifs representing Canada, the United States and Mexico. And for the first time in men’s World Cup history, matches will be played with a four-panel ball.

But with so few panels, has Adidas made the ball too smooth? That is the trap engineers fell into with the Jabulani ball used at the 2010 World Cup in South Africa that became notorious for sudden dips and swerves, which made goalkeepers’ lives far trickier.

You do not want the World Cup ball to feel like the start of a science experiment once it is in the air. And if it behaves strangely, players and goalkeepers notice immediately.

The evolution of soccer balls

World Cup balls have come a long way over the decades. If you go back to 1930, the ball looked very different. The first World Cup final used two different leather balls: Argentina’s Tiento in the first half and Uruguay’s T-Model in the second. Both were hand-sewn, multipaneled balls, inflated through a bladder opening that had to be tied off and tucked back beneath the laces. In damp conditions, the leather absorbed water, making the ball heavier and less predictable in play.

By 1994 – when the United States last hosted the men’s tournament – the official ball, Adidas’ Questra, had evolved into a foam-based design. The modern World Cup ball is no longer just stitched leather. It is an engineered aerodynamic surface.

Trionda pushes that evolution further. It has only four panels, the fewest in men’s World Cup history, which have been thermally bonded – melded together using heat and adhesive.

Fewer panels might suggest less total seam length and therefore a smoother ball. And smoothness matters because the thin boundary layer of air clinging to the ball determines where the flow separates, how large a wake forms, and how much drag the ball experiences.

The Trionda has intentionally deep seams, three pronounced grooves on each panel and fine surface texturing.

But will these textures and grooves do the trick? To find that out, my colleagues and I measured the ball’s seam geometry and overall aerodynamic behavior. We compared it with Trionda’s four predecessors: 2022’s Al Rihla, 2018’s Telstar 18, the Brazuca used in 2014 and the Jabulani in 2010.

What the measurements show

In our wind tunnel tests at the University of Tsukuba, we measured something called the drag coefficient, which is a way of describing how much air resistance a ball experiences as it moves.

Using this data, we gained insights into how the airflow changes around the ball after it is kicked. The tests helped identify the drag crisis, the speed range in which changes in the boundary layer and flow separation produce a sharp change in drag, which can alter the ball’s acceleration, trajectory and range.

We found that the Trionda is effectively rougher than those predecessors.

Trionda reaches its drag crisis at a lower speed, at about 27 mph (43 kph). That is below the roughly 31-40 mph (50-65 kph) range for Al Rihla, Telstar 18 and Brazuca, and far below Jabulani’s roughly 49-60 mph (79-97 kph) range, depending on orientation.

Why does all that matter? Because a ball can feel ordinary off the boot and still behave differently in flight. When the drag crisis occurs in the middle of game-relevant speeds, small changes in launch speed, orientation or spin can shift the ball from one aerodynamic regime to another.

That was Jabulani’s problem. Once kicked with little spin, it had a tendency to slow down too much as it passed through its critical-speed range.

Trionda does not look like that kind of ball. It has a more steady and consistent drag coefficient in the range of speeds associated with corner kicks and free kicks.

But there is a trade-off. Our measurements also showed that once Trionda enters the higher-speed, turbulent-flow regime, its drag coefficients are somewhat larger than those of Brazuca, Telstar 18 and Al Rihla.

In plain language, that suggests a hard-hit long ball may lose a little range.

In our simulations, the difference is not huge. But it is large enough that players may notice long kicks coming up a few meters short.

It is also important to note that we tested a nonspinning ball. As such, our results do not provide a prediction of every pass, clearance or free kick fans will see this summer. Balls in flight often spin due to off-center kicks. That, along with altitude, humidity, temperature and air pressure all influence how a ball flies through the air once kicked.

The big test yet to come

Fewer panels and more texturing aren’t the only differences with the new ball.

Trionda also carries technology that has little to do with its flight and a great deal to do with officiating. Like Al Rihla, Trionda includes “connected-ball technology” that lets computers know when the ball is kicked, helping with offside decisions.

But the architecture has changed. In 2022, the measurement unit was suspended at the center of the ball. With Trionda, it sits in a specially created layer inside one panel, with counterbalancing weights in the other three panels. The chip sends data to the video assistant referee, or VAR, system and the tournament’s semi-automated offside system.

That tweak will help referees, but will the new ball in general help or hinder players?

The evidence from our tests suggests that the ball won’t be behaving in a way that leads to baffling and erratic flight.

But the more intriguing possibilities are subtler and outside the scope of our tests. Will the grooves on Trionda help players generate more backspin on the ball, generating more lift and possibly offsetting Trionda’s somewhat larger high-speed drag coefficient?

That is why I keep studying World Cup balls both in the lab and through their behavior in play. Every four years, a new design offers a fresh way to watch physics enter the game, not in theory, but in the movement of an object in which every player on the soccer field must place their trust.

John Eric Goff currently works as a visitor in the Department of Physics at the University of Puget Sound in Tacoma, Washington. Following the conclusion on 30 June of that one-year appointment, he will start on 1 July as Professor of Engineering Practice in the Weldon School of Biomedical Engineering and the School of Mechanical Engineering at Purdue University.

Ten years after “Hillbilly Elegy” catapulted its author into public view, JD Vance is publishing a new memoir, “Communion: Finding My Way Back to Faith.” The vice president explains the book as a sort of self-help guide for the spiritually lost: “… by sharing my journey I might be helpful to others – Catholic, Protestant, or otherwise – who are seeking reconciliation with God.”

Scheduled for publication in June 2026, “Communion” promises “an intimate account” of its author’s religious journey. But the Catholicism to which Vance converted in Cincinnati in 2019 is quite unlike the evangelism he encountered in his childhood, famously described in “Hillbilly Elegy.”

As a historian of religion in Appalachia and the Midwest, I find America’s religious mosaic endlessly fascinating. Vance’s journey from Protestantism, to atheism, to Catholicism, not to mention his marriage to a Hindu woman, reflects the diversity of the United States.

My own experiences teaching in Vance’s hometown of Middletown, Ohio, suggest that America’s Midwestern communities, tarnished by “Rust Belt” stereotypes, are as dynamic and as changing as everywhere else – including in matters of faith.

Nearby Cincinnati, where Vance was confirmed at a Dominican priory, is a case in point and a window into Catholicism’s history in the American heartland. For more than a century, anti-Catholicism was a powerful force in culture and politics – yet, time and again, religious pluralism triumphed.

Scots-Irish settlers

“To understand me, you must understand that I am a Scots-Irish hillbilly at heart,” Vance declared in his first memoir.

The Scots-Irish played an outsized role in history. Initially, these Protestants were from Scotland, but they moved to Ireland in the 17th century. “Planted” by the British Crown as a form of colonization, these immigrants riled the Catholic majority whose lands they occupied.

Later, many crossed the Atlantic and settled the Colonial American backcountry. Their distinctive influence shaped the “hillbilly” culture of Appalachia.

The faith of these settlers kindled a fervent Protestant piety, found in the Great Revival of the Ohio Valley frontier. In this early 19th-century rebirth of backcountry religion, traveling ministers preached a fiery gospel of grace, stirring large crowds with their open-air sermons.

Queen City

Boundaries between urban and rural America were always porous. By 1830 a quarter of Ohio’s 1 million inhabitants clustered in the state’s southwestern corner. Cincinnati was the heart of this region: the “Queen City” of the United States’ expanding Western frontier.

It had become a hub of Catholic immigrants from Germany and Ireland – and a center for anti-Catholic preaching and anti-immigrant politics. In 1835, leading Protestant evangelist Lyman Beecher infamously denounced immigrants “rushing in like the waters of the flood” and argued the Vatican and Catholic schools posed dangers for America.

Amid such prejudice, Protestant Irish Americans embraced the term Scots-Irish to distinguish their more established population from recent Catholic arrivals. Many of these Catholic newcomers, fleeing famine and persecution, were disparaged as poor, illiterate and superstitious.

Yet despite alarmism and periodic violence, including ethnic riots in 1855, Cincinnati’s sectarian relations were surprisingly pragmatic, shaped by a sense of shared civic endeavor. Protestants welcomed the city’s first Catholic church, for example, and often sent their children to the Catholic parochial schools. Many converted to Catholicism, including wealthy philanthropists.

In 1837, Cincinnati’s Catholic Bishop, John Baptist Purcell debated Protestant preacher Alexander Campbell on the merits of Catholic religion for several days before a crowded audience. Both debaters claimed victory, and proceeds from the published debates were evenly split between Catholic and Protestant charities in Cincinnati.

Changing country

By the mid-19th century, the city’s Catholics, while still a minority, were larger than any single Protestant denomination and central to the cultural landscape.

At the time, Catholics represented only 5% of the U.S. population. That percentage would triple by the turn of the century, due to immigration from southern and eastern Europe.

Anti-Catholic backlash continued into the 20th century, along with other forms of religious prejudice. For example, the U.S. Immigration Act of 1924 restricted immigration from parts of Europe heavily populated by Jews and Catholics. Animosity once focused on immigrants from Germany and Ireland shifted to those from Italy and Russia.

Bias against Catholics remained a robust force in Appalachian politics, too. Leading up to the 1960 Democratic primary, John F. Kennedy campaigned tirelessly in West Virginia, considered a tough arena for a Harvard-educated Catholic but critical to his electoral strategy. His success in the Mountain State defied the myth that a Catholic candidate could never win the White House.

Turn toward ‘Communion’

Southern Ohio, where Vance grew up and converted to Catholicism, is deeply Midwestern. But its heritage has been influenced by the wave of workers who left Appalachia in the mid-20th century looking for jobs, including Vance’s family.

As Vance wrote in a 2020 essay for Lamp magazine, which addresses Catholic issues, his early ideas of Catholicism were negative ones – assuming, for example, that the church “rejected the legitimacy of Scripture.”

As a young man, he drifted away from faith altogether. During his days at Yale Law School, however, Vance discovered a curiosity that drew him toward Catholicism, inspired by thinkers from Silicon Valley mogul Peter Thiel and French philosopher René Girard to the fourth-century theologian St. Augustine.

Vance wrote in his essay, “I often wonder what my grandmother” – a woman with Christian beliefs, but skepticism of institutional religion – “would have thought about her grandson becoming a Catholic.”

Today, 1 in 5 U.S. adults is Catholic, and another 9% consider themselves “cultural Catholics.” America’s prejudice toward their tradition has eroded. Six out of nine Supreme Court justices are Catholic, along with 28% of Congress.

In fact, Vance’s new faith highlights a growing alliance between culturally conservative elements of American Catholicism and America’s religious right, dominated by conservative Protestants since its emergence in the 1970s.

Lately, this alignment has come under strain, in part reflecting American-born Pope Leo XIV’s wariness toward U.S. policies, such as the war in Iran. Nowhere have such spats been more ironic than in Vance’s rebuke of the pope. After Leo remarked that Jesus’ followers are “never on the side of those who once wielded the sword and today drop bombs,” the vice president warned, “If you’re going to opine on matters of theology, you’ve got to be careful.”

It will be interesting to see how such tensions play out in years to come.

Matthew Smith does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.

Every four years, the men’s World Cup delivers some certainties. The pitch dimensions are tightly regulated, offside is signaled with a flag, and referees end the match with a blast of a whistle. But one key piece of equipment is changed on purpose: the ball.

Adidas, which has supplied World Cup soccer balls since 1970, introduces a new match ball for every tournament, and with that comes fresh aerodynamic calculations for players. How will it fly through the air, weave and dip?

For the past 20 years, my engineering colleagues in Japan and England and I have put the new balls through their paces, investigating soccer ball aerodynamics. Our work begins by putting balls in wind tunnels to measure drag, side and lift forces. We use the measurements from these tests in trajectory simulations that tell us how the ball will behave in a real-game setting.

That may all sound a little academic, and we do produce an academic paper on our findings. But what our data indicates could mean the difference between a goal or a miss for strikers, a save or a blunder for goalkeepers, and jubilation or heartache for fans.

At the World Cup, the ball is the most important piece of equipment in the biggest tournament of the world’s most popular sport.

This year’s ball, the Trionda, is especially interesting. When FIFA and Adidas unveiled it in fall 2025, the first thing many people noticed was the color and the paneling.

The ball’s red, blue and green graphics correspond to the three host countries, with maple leaf, star and eagle motifs representing Canada, the United States and Mexico. And for the first time in men’s World Cup history, matches will be played with a four-panel ball.

But with so few panels, has Adidas made the ball too smooth? That is the trap engineers fell into with the Jabulani ball used at the 2010 World Cup in South Africa that became notorious for sudden dips and swerves, which made goalkeepers’ lives far trickier.

You do not want the World Cup ball to feel like the start of a science experiment once it is in the air. And if it behaves strangely, players and goalkeepers notice immediately.

The evolution of soccer balls

World Cup balls have come a long way over the decades. If you go back to 1930, the ball looked very different. The first World Cup final used two different leather balls: Argentina’s Tiento in the first half and Uruguay’s T-Model in the second. Both were hand-sewn, multipaneled balls, inflated through a bladder opening that had to be tied off and tucked back beneath the laces. In damp conditions, the leather absorbed water, making the ball heavier and less predictable in play.

By 1994 – when the United States last hosted the men’s tournament – the official ball, Adidas’ Questra, had evolved into a foam-based design. The modern World Cup ball is no longer just stitched leather. It is an engineered aerodynamic surface.

Trionda pushes that evolution further. It has only four panels, the fewest in men’s World Cup history, which have been thermally bonded – melded together using heat and adhesive.

Fewer panels might suggest less total seam length and therefore a smoother ball. And smoothness matters because the thin boundary layer of air clinging to the ball determines where the flow separates, how large a wake forms, and how much drag the ball experiences.

The Trionda has intentionally deep seams, three pronounced grooves on each panel and fine surface texturing.

But will these textures and grooves do the trick? To find that out, my colleagues and I measured the ball’s seam geometry and overall aerodynamic behavior. We compared it with Trionda’s four predecessors: 2022’s Al Rihla, 2018’s Telstar 18, the Brazuca used in 2014 and the Jabulani in 2010.

What the measurements show

In our wind tunnel tests at the University of Tsukuba, we measured something called the drag coefficient, which is a way of describing how much air resistance a ball experiences as it moves.

Using this data, we gained insights into how the airflow changes around the ball after it is kicked. The tests helped identify the drag crisis, the speed range in which changes in the boundary layer and flow separation produce a sharp change in drag, which can alter the ball’s acceleration, trajectory and range.

We found that the Trionda is effectively rougher than those predecessors.

Trionda reaches its drag crisis at a lower speed, at about 27 mph (43 kph). That is below the roughly 31-40 mph (50-65 kph) range for Al Rihla, Telstar 18 and Brazuca, and far below Jabulani’s roughly 49-60 mph (79-97 kph) range, depending on orientation.

Why does all that matter? Because a ball can feel ordinary off the boot and still behave differently in flight. When the drag crisis occurs in the middle of game-relevant speeds, small changes in launch speed, orientation or spin can shift the ball from one aerodynamic regime to another.

That was Jabulani’s problem. Once kicked with little spin, it had a tendency to slow down too much as it passed through its critical-speed range.

Trionda does not look like that kind of ball. It has a more steady and consistent drag coefficient in the range of speeds associated with corner kicks and free kicks.

But there is a trade-off. Our measurements also showed that once Trionda enters the higher-speed, turbulent-flow regime, its drag coefficients are somewhat larger than those of Brazuca, Telstar 18 and Al Rihla.

In plain language, that suggests a hard-hit long ball may lose a little range.

In our simulations, the difference is not huge. But it is large enough that players may notice long kicks coming up a few meters short.

It is also important to note that we tested a nonspinning ball. As such, our results do not provide a prediction of every pass, clearance or free kick fans will see this summer. Balls in flight often spin due to off-center kicks. That, along with altitude, humidity, temperature and air pressure all influence how a ball flies through the air once kicked.

The big test yet to come

Fewer panels and more texturing aren’t the only differences with the new ball.

Trionda also carries technology that has little to do with its flight and a great deal to do with officiating. Like Al Rihla, Trionda includes “connected-ball technology” that lets computers know when the ball is kicked, helping with offside decisions.

But the architecture has changed. In 2022, the measurement unit was suspended at the center of the ball. With Trionda, it sits in a specially created layer inside one panel, with counterbalancing weights in the other three panels. The chip sends data to the video assistant referee, or VAR, system and the tournament’s semi-automated offside system.

That tweak will help referees, but will the new ball in general help or hinder players?

The evidence from our tests suggests that the ball won’t be behaving in a way that leads to baffling and erratic flight.

But the more intriguing possibilities are subtler and outside the scope of our tests. Will the grooves on Trionda help players generate more backspin on the ball, generating more lift and possibly offsetting Trionda’s somewhat larger high-speed drag coefficient?

That is why I keep studying World Cup balls both in the lab and through their behavior in play. Every four years, a new design offers a fresh way to watch physics enter the game, not in theory, but in the movement of an object in which every player on the soccer field must place their trust.

John Eric Goff currently works as a visitor in the Department of Physics at the University of Puget Sound in Tacoma, Washington. Following the conclusion on 30 June of that one-year appointment, he will start on 1 July as Professor of Engineering Practice in the Weldon School of Biomedical Engineering and the School of Mechanical Engineering at Purdue University.