Defining Gravity: 30 Years of Saturday Morning Physics

(Left) SMP appeals to the next generation of scientists with activities such as this stationary bicycle connected to a generator that powers a set of light bulbs. The orange ball is a large pendulum that was used to demonstrate the conservation of energy and the transformation of energy from potential to kinetic. (Right) Students Cyprus Gabriel-Menegay and Xinzhi Zhou explore an “accretion disk” demonstration: a rubber sheet model of spacetime.

The concept of SMP began at Fermilab, the particle accelerator and physics lab just west of Chicago. Physicist Leon Letterman started the program to give postdoctoral researchers the opportunity to present their research and engage the public.

Physicist Dante Amidei was at Fermilab and brought the concept to U-M when he became a professor in 1990. The U-M lectures began in October 1995 with postdoctoral researcher Robert Welsh speaking about brain MRIs and xenon, the noble gas.

“Five minutes before it started, people were packed out into the hallway,” recalls Chupp, who worked in the lab with Welsh at the time. “They had to delay the start because they didn’t want to turn anyone away.” They’d booked a lecture hall that held 40 people, “but more than 100 people showed up.”

The lecture was moved to a larger venue in the Dennison Building (now Weiser Hall), where it has remained. Over the decades the lectures have expanded beyond postdoctoral researchers to include faculty and scientists in a variety of fields and positions from all over the world. Chupp was there on the ground floor. “I was hooked from the start,” he says.

“It’s different from teaching physics. It’s great to teach scientists, but I prefer to teach classes that are out of the norm because of the public engagement. You’re making people feel like they’re learning something, making them laugh, entertaining them.”

Many of the staff and faculty who make SMP a success, from left to right: Monika Wood, Timothy McKay, Nicholas Arnold, Dante Amidei, Christine Aidala, Sean Reilly, Carol Rabuck, and Timothy Chupp.

Chupp is quick to note that he doesn’t do any of this alone. Key to the program’s success are Carol Rabuck and Monika Wood. The lab supports the SMP lectures by helping create and execute demonstrations that help audiences grasp what’s being taught.

“Some people don’t have a topic that lends itself naturally to a demonstration, but I try my hardest to find something that fits,” says Wood, who manages the Physics Lecture Demonstration Laboratory. “Like imagining that the fabric of space-time is a sheet of fabric. It’s not exact, but it’s an analogy that lets you say, ‘Oh, I can kind of see how that works.’”

Rabuck is the administrator for Saturday Morning Physics and a marketing communications specialist for the Department of Physics, and the behind-the-scenes maverick, coordinating countless SMP details.

Wood, Rabuck, Chupp, and many others go above and beyond to make SMP a success. For example, Wood’s lab is geared primarily toward supporting U-M classes and, last year, Wood and her two colleagues did 2,567 demos for 30 classes, not including SMP.

Wood also helped launch the virtual SMP physics programs during the COVID-19 pandemic. “When COVID hit, we didn’t want SMP to be a casualty,” she says. “The transition to live webcasts made sense because the world is moving in that direction. We want to evolve with our audience.”

Several videos have been viral successes: “The Many Worlds of Quantum Mechanics” with physicist Sean Carroll, professor at Johns Hopkins University and host of the Mindscape podcast, has more than 131,000 views; “The Physics of Complex Systems,” with Mark Newman, the Anatol Rapoport Distinguished University Professor of Physics in LSA, has 18,000 views; “The Truth about Entropy” with Sharon Glotzer from U-M’s Department of Chemical Engineering has 4,100 views.

Saturday Morning Physics has evolved to a hybrid format in which they can reach a much larger audience online while still catering to attendees who can visit in person. At right, Monika Wood, who manages the Physics Lecture Demonstration Laboratory, demonstrates eddy-current braking.

There have been more than 400 lectures in SMP’s 30-year history. With an average attendance of 200 people per lecture, that’s a reach of around 80,000 people. Add in the YouTube views, and it’s an exceptional feat of science outreach.

But Chupp still has concerns about impact and wants to be doing more. “There is a huge effort to discredit science,” Chupp says, citing data from the National Science Board and the Pew Research Center that shows a decreasing number of people think that scientists act in the best interests of the public. When asked “Do you trust science?”, 20 percent of people said no.

“We shouldn’t go out and say, ‘trust us,’” Chupp says. “Instead, we should show what and how we do science and explain that it’s a human endeavor. Science is not perfect, but it’s also very rigorous and reproducible.”

That’s the heart of SMP’s work, but it’s work that requires investment. Each SMP lecture costs about $6,500. The Van Loo Family Endowment pays for the postdoctoral lectures each year. But the other talks—astronauts explaining space, award-winning physicists explaining dark matter, doctors explaining vaccines—are funded separately.

“From the start, there has been a dedicated effort among faculty, staff, and donors to make SMP happen and to make it more,” says Chupp. “There have been ideas to take it on the road or expand venues, but it’s not inexpensive, and we have to pay people to work on a Saturday.”

As the SMP team members strive to amplify its reach, they will continue the work of presenting lectures and fulfilling their mission to educate and entertain.

Astronaut Josh Cassada first visited SMP through a livestream from the International Space Station, then later followed it with an in-person appearance and talk. Photography by Erin Kirkland/Michigan Photography

In 2023, astronaut Josh Cassada came back to SMP for a lecture that was multigenerational, packed with school kids, and filled with fun. “We had a question from a three-year-old,” Chupp laughs. 

Coordinating with Cassada from the space station and for a second time was the most work Chupp had ever put into SMP, and the lecture remains one of his favorites because of its impact—particularly how the science excited kids and sparked curiosity. “It made me realize that any amount of energy and effort I put into SMP is worth it,” he says.

Photography by Amanda Mae Photography and courtesy of the Department of Physics unless otherwise noted.