Pi Day Celebrates Math Constant's Endless Uses

From rockets to cancer research, pi is embedded in our lives in unexpected ways.

Mar. 14, 2026 at 11:18pm by Ben Kaplan

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Math enthusiasts and dessert lovers unite every March 14 to celebrate Pi Day, marking the first three digits of the mathematical constant pi. While pi is best known for its use in calculating the area of circles, its applications extend far beyond geometry into fields like aerospace engineering, biomedical research, and even COVID-19 testing. Experts explain how this fundamental mathematical concept is woven into the fabric of our world in surprising and innovative ways.

Why it matters

Pi Day highlights how a single mathematical constant can have profound and far-reaching implications across diverse scientific disciplines. By understanding pi's ubiquity, we gain insight into the interconnectedness of various fields and the power of mathematics to unlock new discoveries and technological advancements.

The details

Pi, the ratio of a circle's circumference to its diameter, is used in countless formulas and calculations, from spacecraft propulsion to cancer research. In aerospace engineering, pi is essential for everything from tracking the position of distant space probes to designing communication antennas. In biomedical research, pi is crucial for creating tiny polymer particles that act as "test tubes" for studying cell functions and finding potential cancer-fighting antibodies. Even the fluid dynamics behind COVID-19 testing kits rely on pi-based calculations.

  • Pi Day is celebrated annually on March 14, the date that represents the first three digits of pi (3.14).
  • The Pi Day celebration at the Exploratorium science museum in San Francisco began in 1988, started by physicist Larry Shaw.

The players

Larry Shaw

A physicist at the Exploratorium science museum in San Francisco who created the Pi Day celebration in 1988.

Sam Sharkland

The program director of public programs at the Exploratorium, who worked with Larry Shaw before his death in 2017.

Artur Davoyan

A professor of mechanical and aerospace engineering at the University of California, Los Angeles, who researches new propulsion systems for space exploration.

Dino Di Carlo

The chair of the bioengineering department at the UCLA Samueli School of Engineering, who conducts research on using tiny polymer particles to study cells and find potential cancer-fighting antibodies.

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What they’re saying

“He had a very open and expansive view of the world and saw an opportunity with this number, mathematical concept, to invite people into the joy of mathematical learning.”

— Sam Sharkland, program director of public programs at the Exploratorium

“As an engineer and scientist, (pi) is just a part of life. Maybe I've taken it for granted.”

— Dino Di Carlo, chair of the bioengineering department at the UCLA Samueli School of Engineering

What’s next

The Exploratorium plans to host its annual Pi Day celebration on March 14, 2027, featuring a procession where hundreds of visitors march around the pi shrine, each carrying a digit.

The takeaway

Pi's ubiquity in science and technology underscores the power of mathematics to unlock new discoveries and innovations across diverse fields. Pi Day serves as a reminder to appreciate the elegance and importance of this fundamental constant, which is woven into the fabric of our world in ways we often take for granted.