Barney the Purple Dinosaur dangled precariously above the floor, suspended electromagnetically from a hydraulic lift in one of the Science Center lecture halls.

The stuffed dinosaur was waiting patiently to be hit with a steel ball shot from a spring-powered cannon, so that Robert P. Kirshner ’70, an astronomy professor, could demonstrate the independence of the horizontal and vertical components of a projectile’s velocity.

Moments later, the cannon ball launched through an infra-red photo gate, triggering a circuit that shut down the electromagnet and releasing Barney into the parabolic path of the steel ball. The demo went off without a hitch—but years later, what the Science Center’s lecture demonstrations team remembers is not their careful execution or planning, but a rather unanticipated finishing touch.

“The collision with the wall must have flipped a switch in Barney’s voicebox,” Lecture Demonstration Services Manager Wolfgang H. E. Rueckner recalled, because when Professor Kirshner went to pick up the battered plush doll, leaning over so that his microphone was directly above Barney’s head, the doll said quite audibly: “I need a hug.”

Amidst his students’ spirited laughter, Kirshner readily obliged.

The four lecture demos team members are the engineers and puppet-masters behind the nearly 1,000 demos available for execution each year in Harvard’s science classes and programs. Coupling construction with chemistry and artistry with physical phenomena, the team serves as an integral, and often invisible, coordinating mechanism behind the more memorable—and explosive—elements of Harvard science courses.

“We hope to add to the educational experience and make these scientific concepts more understandable,” Rueckner explained. “We’re doing it visually and experimentally, hopefully with a little flair, and humor, and showmanship so that it can be remembered.”

HYSTERICAL INSTRUMENTS

If you’ve ever wandered the wrong direction on your way to the freshmen mailboxes, you may have stumbled across a doorway in the Science Center basement with the words “Collection of Hysterical Scientific Instruments” plastered across its frame. No, not Historical. Hysterical.

The label alone should be enough to warn you that you’re crossing into rather unconventional scientific territory down in the depths of the 36-year-old Science Center.


Across the hall, the lecture demos office is a scientifically-minded tinkerer’s heaven: books detailing experiments from decades past are stacked on shelves along the wall, while every available surface is riddled with microscopes, old clocks, crushed trash cans, revolving mobiles, artfully arranged yardsticks, and spare lab coats.

“A lot of it is kind of beautiful,” said the team’s chemistry expert, Daniel B. Rosenberg ’84, whose hobbies include deconstructing hard drives and assembling odds and ends into aesthetically-pleasing arrangements (like the shrine to Ben Franklin beside his desk).

The playful atmosphere and juxtaposition of cutting-edge computers with outdated scientific equipment somewhat encapsulate the unique nature of the lecture demos mission.

Demonstration science, Rueckner explained, is more focused on clarity, simplicity, and general principles than research science, which prioritizes precision, minute detail, and cutting-edge technology.

“Here in education, we basically dabble in all [areas], and we are concerned about how to make all these abstract ideas accessible in terms of pedagogy,” Rueckner said.

But using old equipment and leaving room for error can actually add to a demo rather than detract from it, said Douglass B. Goodale, another demo team member.

“By the nature of what we do, because we set things up quickly and because our apparatuses have to be portable, there’s more of an opportunity for experimental error,” he said. “Students see that science is not always the ideal world.”

Because the team members build most of their own equipment in an extensive machine room, they focus on creative solutions to complicated problems.

“Instead of spending all that time in lab adding equipment to make it work just right, we have to make it more clever,” Rosenberg said. “We ask ourselves, ‘how can we do the most with the least?’”

Even with the rise of technological tools, the team mainly relies on instruments they built or acquired years ago—though they do use computers to make quick measurements, project images, and create models.


“It’s good that we still have more antique apparatuses, like electroscopes, corktubes, and galvanometers,” said Allen R. Crockett, the fourth team member. “Things that have a historical place.”

RENAISSANCE MEN

Harvard has featured demonstrations in its lectures since the 1600s—Benjamin Franklin himself actually donated collections of electrical instruments to Harvard back in the day, Rueckner noted.

“The collection of lecture demos that we started with are actually demos we inherited from the original physics, chemistry, geology, and astronomy departments,” said Rueckner, who started helping with lecture demos in 1979, back when the university had only one man running the demo show. Since 1988, the team has had four full-time members.

Rueckner, who teaches an Extension School physics course, holds a Ph.D. in atomic and molecular physics. Goodale started his career as a physics researcher as well, but also brought six years of work as a carpenter to the table when he joined the team 20 years ago.

Rosenberg, who studied the physical sciences and says he’s “always been a maker of things,” and physics and computer science expert Crockett (who came aboard three years ago) round out the current crew.

Beyond courses, the team helps out with student organizations like ExperiMentors, Project Teach, the Harvard Foundation’s science seminar, and the mid-December Holiday Lectures, which have featured demos about chocolate, bacteria, and cholera.

“Every day is always something different—I enjoy being able to work with my hands, be on my feet, not just sit in a cubicle all day,” Crockett said.

RIPPLE TANKS & ROCKET CARS

The lecture demos office opens into an extensive machine room—replete with power tools, a welding station, and a lathe for shaping metals—which used to be run by a professional machinist who taught undergraduate classes in building and welding.


The lecture demos team works in the shop to build spark chambers, giant jungle gyms, bicycles that generate electricity, ripple tanks, and rocket cars that decorate the halls of the storage room across the hall.

“Those guys seem to be very good with their hands,” said Gregory Tucci, Senior Lecturer in Chemistry and Chemical Biology, who has worked with the lecture demos team for years. “With a lot of these demos, it has to be something that you bring into the world yourself.”

In the ante-chamber of the storage room, the walls are lined with shiny “relativity” train tracks, a pool table that showcases inelastic and elastic collisions, and a vintage Carbonari light source, originally a movie projector.

Some of the items are straight out of a science fiction movie: for example, a giant yo-yo, an armillary sphere, a dozen bowling balls from a Newton’s cradle machine project that never materialized, and a cage full of mousetraps to simulate the type of chain reaction that characterizes a nuclear explosion all adorn the space.

“When I show new faculty around, I always show them the demonstrations,” Tucci said. “There are not a lot of places in the country who have what we have at our disposal.”

Over in the physics wing of the prep room, a 1934 Tesla coil from Radcliffe sits beside a tub full of wooden vectors, which is around the corner from a set of French tuning forks from the 1800s.

“We have close to 1,000 demos,” Reuckner said. “When I came here, it was a tenth of that.”

On the chemistry side are cabinets with 80-year-old bromine and chlorine, as well as a large model of a double helix that’s been in the works for about 15 years, Rosenberg said.

Some of the items are simply enormous, and many are draped with stuffed animals that play a part in various demos. One stuffed toy holds a special place in the team’s heart: their mascot, a small stuffed brown dog named “Demo Dog.”

“He went to Harvard,” Goodale said. “He just never went home.”


Knowing their way around the storage and prep rooms—and being able to grab a device at a moment’s notice—are all part of the lecture demo team’s job description. After all, even the most complex demos must be assembled in just about seven minutes, the time between two back-to-back classes.

A DEMO’S WORTH 1,000 WORDS

When setting up demos, the team must guide professors who have varying levels of familiarity with demonstration science, they said. Newer faculty often need more help brainstorming, while seasoned professors may need no more than an expert backstage to flip a switch if something goes wrong.

“They’re great, they try to anticipate your needs, they try to keep things in repair,” Kirshner said. “You want to make sure the brakes work on the rocket car, for example.”

The team sometimes likes to pull little jokes, Tucci added—for example, a “little demonstration bear” tends to pop up in the most unexpected places during demos.

But all jokes aside, professors and students indicate that demonstrations add excitement, suspense, and memorability to any lecture.

“Having nature tell you how she works is the most convincing tool because after all, in science, we’re trying to deduce how the world works,” said Eric Mazur, a physics and applied physics professor who researches science education strategies.

But he said that a demonstration is not necessarily effective in a vacuum, so to speak—the lecturer must properly prepare students to absorb the meaning of the demo.

Mazur has conducted studies evaluating whether predicting and discussing demo outcomes affect the degree to which students remember the principles illustrated.

“Adding just the prediction increased the students’ ability to correctly remember very significantly,” Mazur said.


He said that when a new mental model is required to explain the result of a demo, it’s crucial for students to take time to reconstruct their mindsets before moving on—or else they are in danger of remembering the principle incorrectly.

“What happens is that your brain adjusts your memory to the model rather than the model to the observation,” he said. But when students invest in thinking before a demo, “if there is a cognitive dissonance, it’s stronger, and they’re more likely to say ‘woah, let me figure this out, why was I wrong?’” he said.

Kirshner commented that a sense of danger—especially the danger that the professor might get injured—is always exciting (and potentially amusing) for students.

“When they’re exploding things and they put on safety goggles, you know they’re really serious,” said Mary M. Griffin ’13, a student in Physical Sciences 1 who says that demos in the class serve not only to wake students up but give them an “exciting context in which to absorb the material they’re learning.”

By working thoughtfully—and often quite inconspicuously—at the nexus of construction, creativity, innovation, and education, the demo team is able to spread their enthusiasm for science to a wider audience through demonstrations large and small, complex and simple.

“Look, science is real, tangible things—you want to hear it, see it, feel it, smell it, taste it,” said Tucci, in enumerating the virtues of a well-executed demonstration. “It’s not just symbols on a blackboard anymore, it’s real, visceral stuff.”

—Staff writer Julie R. Barzilay can be reached at jbarzilay13@college.harvard.edu.