Pi Day: How the Constant Shapes Science and Technology

From rocket science to cancer research, the mathematical constant pi is embedded in our everyday lives.

Mar. 14, 2026 at 12:38pm

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Pi Day, celebrated annually on March 14, commemorates the mathematical constant pi (π), which represents the ratio of a circle's circumference to its diameter. While pi is often associated with calculating the area of a circle or volume of a cylinder in school, its applications extend far beyond the classroom. This article explores how pi is used in cutting-edge scientific fields, from aerospace engineering to biomedical research.

Why it matters

Pi is a fundamental mathematical constant that underpins a wide range of scientific and technological advancements. By understanding how pi is applied in various disciplines, we can appreciate the ubiquity of mathematics in our daily lives and the crucial role it plays in driving innovation and discovery.

The details

In aerospace engineering, pi is used in formulas for spacecraft motion, materials science, and propulsion systems. Researchers like Artur Davoyan at UCLA rely on pi to calculate the position of Earth in relation to distant space probes and design antennas for communication. In bioengineering, Dino Di Carlo's work on creating tiny polymer droplets to study cells involves pi-based calculations for surface tension and fluid dynamics. These droplets are used to develop new diagnostic tests, such as a 20-minute Lyme disease test.

  • Pi Day is celebrated annually on March 14, the date that represents the first three digits of the mathematical constant pi.
  • The Pi Day celebration at the Exploratorium science museum in San Francisco begins at 1:59 p.m., signifying the next three digits of pi.

The players

Larry Shaw

A physicist at the Exploratorium science museum in San Francisco, who created Pi Day 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 creating tiny polymer droplets to study cells and develop new diagnostic tests.

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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 (boston.com)

“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 (boston.com)

The takeaway

Pi, a seemingly simple mathematical constant, is woven into the fabric of our scientific and technological advancements. From powering space exploration to enabling groundbreaking biomedical research, pi's ubiquity underscores the profound impact of mathematics on our understanding and shaping of the world around us.