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Science Bob

A Rockstar Among Third Graders

by Justine Hofherr

Deep inside the heart of Bernon Hall, the primary academic building of the Fessenden School — an all-boys school in Newton — 16 third-graders watched with rapt attention as their teacher, “Science Bob” prepared a demonstration.

Standing before a stage ensconced in blue velvet curtains, Bob Pflugfelder told the boys what he was about to do: mimic a grain mill explosion.

“A long time ago,” Science Bob began, “People would grind up flour in flour mills using giant stones.” He spread his thin arms for emphasis. “Some of the flour would go into the air, which was harmless on its own. But occasionally, someone would smoke a cigarette, and…BOOM! That was all it took. There would be a huge flour mill explosion.”

Science Bob was teaching chemical reactions that week. He explained that if you combine fire with airborne flour particles and surround them with just enough oxygen in an enclosed space, huge explosions could occur.

A couple boys scooted forward on their black metal folding chairs. They knew there was a reason class was moved to the Performing Arts Center.

“Let’s create that same reaction in this bucket,” said Science Bob.

“Yes!” the boys shouted. Science Bob smiled.

After carefully lighting a thin black candle, Science Bob set it down inside a large glass bucket. He then took a dropper and added lycopodium powder to the bucket.

“More! More! More!” the boys chanted.

Science Bob paused. He held up the lid to the container. “When I put the lid on this, and blow through this tube, what do you think will happen?”

“The lid will pop off!” one boy shouted.

Science Bob didn’t answer, tilting his head mysteriously. He slammed down the lid. He put on his safety goggles.

Then he began a countdown:

“Eight! Seven! Six!”

The boys took over: “Five! Four! Three! Two! One!”

Science Bob took a deep breath—and blew.

KABOOM! The lid flew off the container and clattered to the floor, just as a fiery explosion erupted into the air.

The boys clapped wildly. A chair tipped over and was quickly righted. “Yay!” they cheered, “Again! Again!”

“I can see you guys aren’t at all into explosions,” Science Bob said. He removed his goggles with a flourish and adjusted his small round glasses.

“I guess we can do that one more time.” He winked, or maybe there was just something in his eye. It’s hard to tell with him.

Because Science Bob is the most unassuming rock star there ever was.

Let’s back up for a moment.

Bob Pflugfelder hasn’t always been Science Bob, a man who’s not only appeared on Jimmy Kimmel Live! and Live! with Kelly & Michael, but who has also taught science to young Hollywood stars like Haley Joel Osment and Rico Rodriguez of Modern Family.


Science Bob is a pale, soft-spoken man with neatly parted, sand-colored hair, and watery light-blue eyes. He grew up in the suburbs of Westchester, New York, where he spent his childhood exploring. He liked to go for hikes and turn over rocks and logs to inspect the bug ecosystems underneath. He was the kind of kid who enjoyed taking apart the family’s broken toaster to figure out why, exactly, it stopped working one morning. He collected shells.

“A friend of mine had train tracks,” Science Bob said. “He’d like the train part, and I’d be under the table, wiring the tiny houses for lights.” He laughed. “So, uh, yeah, I’ve been a maker and a science enthusiast from the very beginning.”

Science Bob never imagined his passion for science could be a career. So he went to Emerson College in Boston, where he studied television production. Science Bob was particularly fascinated in understanding how science fiction shows worked—not only how they were filmed and produced, but also how they predicted what the future might be like with their high-tech props and costumes.

After graduating, his career took him to Los Angeles—he wanted to be the next Steven Spielberg—and that’s how Science Bob fell into the gig of tutoring young celebrities.

“I was talking to a studio teacher who tutors kids at Warner Bros.,” Science Bob said. “I told him I was really interested in science, and he said they had a student who needed to do a science lab for a third of her grade. She didn’t have any lab equipment in her trailer, though. And I said, ‘Well, I have microscopes and slides and things.’ So I ended up doing that.”

Then, Science Bob’s career took yet another unexpected turn.

After posting videos of some of his science experiments to a (very) young YouTube site, he said he was astonished when producers from Jimmy Kimmel Live called and asked him to do science demonstrations as a guest on the show.

The late night show’s resources allowed Science Bob to do some wild segments. With Kimmel, he’s triggered 1,000 mousetraps in a giant chain reaction. He built a floating magnetic hover board using eight “super strong” 3-inch neodymium magnets. He launched 1,000 rockets made out of film canisters.

Science Bob’s demonstrations seem to come straight out of kids’ dreams. And they are, but they’re also designed to teach scientific concepts to the audience, he said.

In one Jimmy Kimmel episode, Science Bob appeared wearing a homemade tie-dyed lab coat to show how molecules are broken apart. He mixed dish soap, hydrogen peroxide, and a sodium solution in a large flask. The mixture—he called it “elephant’s toothpaste”—bubbled rapidly, and shot out the top of the flask like a geyser in vibrant hues of neon green.

“It gets harder and harder as each episode goes by, because some classic demonstrations have been done year after year, so now we are coming up with things that have never been done before,” he said. As someone who designs his own glass marbles “for fun,” however, Science Bob doesn’t seem like someone who minds challenges.

Kimmel’s producers still call about every six months, he said, and he’s in the midst of planning his next demonstration. Obviously, it’s top secret.

Although Science Bob had a wonderful time living in LA—“I mean, you pull into Warner Bros. studio, and there’s robots and a futuristic city and helicopters flying around on a sound stage”— he said he started to miss New England.

And he was maybe just the tiniest bit burned out, he added. So he moved back.

“I like the leaves changing and the snow falling, so it all balances out,” Science Bob said. “I still get to go on Jimmy Kimmel.” He laughed.

Science Bob currently works at the Fessenden School, an independent day and boarding school for boys from pre-K to ninth grade. Open since 1903, Fessenden is the oldest all-boys junior boarding school in the country and has 513 pupils enrolled.

Science Bob has been there for 12 years, and currently teaches third and fourth-grade science. Teaching at a private school has given him a lot of freedom in the classroom.It has also allowed him to share his childlike wonder for science with a generation that, in his opinion, spends a little too much time looking at a screen.

“Technology gives them access to information and access to different ways of learning,” Science Bob said. He has nothing against technology, “but at the same time, you get to the point where you need to put that stuff down, and look away from the screen, and see how it applies to the world around you. That’s where the fun stuff happens.”

So, he encourages his students to be makers, thinkers, and innovators. His classroom lessons involve destroying old printers, making LED lapel pins, and deconstructing video games to introduce students to coding. Science Bob’s students don’t just read about science in textbooks.

“Oh, and I tend to like things that blow up,” he added.


Large picture windows and ornate school banners bring light and color to the halls of the Fessenden School’s Bernon Hall, which bustles with boys of all ages. On any given day, scattered among desks near a roaring fireplace, some of the boys, wearing identical navy blazers, can be seen hunched over books, reading quietly. Fessenden is all about tradition, rules, and order: Even the school’s motto is “Labor Omnia Vincit,” meaning, “Work Conquers All.”

But Science Bob’s classroom is like entering another universe.

Although the classroom has no windows, the room is bathed in a violet glow. Inside, there is no shortage of things to admire. From the ceiling hangs a model airplane and an undulating black orb that Science Bob said he fashioned from an old KB Toys security camera.

“The one in Waltham was going out of business,” Science Bob explained. “So I asked for the security bubble and bought it. Then I added LED lights and a cool glowing orb I found on Amazon. Soon, I’m going to put clear tubes inside and light it up like fiber optics.” He stared up for a moment as a red, marbled sphere, reminiscent of the planet Jupiter, spun slowly.

Science Bob mentioned that soon his classroom will look even more like a spaceship. He tracked down a movie prop dealer in England in order to buy a fake spaceship consul with tons of buttons. “It’s going to be my desk,” Science Bob said. “It was in the movie Thunderbirds.” He grinned. Students love outer space, he said.

Science Bob’s students also love his vast collection of creepy crawly creatures.

Pictures of foxes, owls, eagles, and wolves dot the wall, and the bust of a Tyrannosaurus Rex and a great white shark burst into the classroom. A plastic container holds two live Madagascar Hissing beetles—the kids can take them home for the weekend, if they want, Science Bob said. And a ball python is coiled inside a heated glass tank. They can’t take that home.

On the day visited, Science Bob was preparing for his next class. Wearing an azure blue button-down shirt, navy tie, and black pants, he scurried among the rows of desks, setting up beakers, flasks, and goggles. It was a big day: Science Bob would be tackling chemistry.

“Teaching is performance art,” he said.

Indeed, Will Tuttle, a Fessenden teacher of programming and robotics, said that Science Bob’s demonstrations excite the faculty as much as the students.

“You’ll see everyone from the pre-K students to the ninth graders to the faculty saying, ‘That was awesome!’” Tuttle said. “He’s incredible.” He’s also a hard act to follow, Tuttle said with a chuckle.


The third-graders arrived to class chanting:

“Bob! Bob! Bob! Bob! Bob!”

Their voices reverberated off the corridor walls and traveled down the hallway as their small shoes shuffled toward the classroom.

“Settle down, boys,” Science Bob said quietly. The students’ shouts turned to whispers as they took their seats. Noting the goggles on his desk, one boy turned to another: “Oh, this is going to be good.”

It was.

Science Bob walked the students through a science demonstration. The boys combined hydrogen peroxide and a few drops of green food dye (for fun). Then, they dropped three level scoops of lycopodium powder into a separate beaker, and added 80 mL water to the powder. It made a thick, creamy mush.

“Is there any evidence we’ve made a compound?” Science Bob asked.

“Noooo,” the boys answered in unison.

Science Bob then explained that they would be pulling the oxygen out of their hydrogen peroxide (H2O2) using yeast, an active ingredient. They added the yeast.

“It looks like oatmeal!” someone said. A few boys leaned their heads over the goop. “It smells like Cheerios!” said one. “It smells like cookies!” said another.

“Now, for the last step—my favorite step,” Science Bob said in a soft voice. “There’s a small chance it could bubble over.”

“YESSSS!” the class roared.

The boys combined the ingredients in the beaker with the ingredients in the flask. Their creations immediately bubbled up like foamy green ghosts, overflowing the flask and spilling onto the students’ plastic trays.

“Ahhh! This is so cool!” The boys clapped wildly. One remarked on the foam’s likeness to Frosty the Snowman.

“It does look like something from a Dr. Seuss story, doesn’t it?” Science Bob said to no one in particular. “It’s beautiful.” He walked from table to table, bending over to inspect the boys’ chemical reactions. “Ah, nicely done,” he said. “Good work.”

Science Bob resumed his spot at the front of the classroom. He waited patiently, arms folded, for the ruckus to die down.

“Now, have we created a chemical reaction?” Science Bob asked. He paused. “Was there fizzing, temperature, or color change?”

The boys looked at one another. One boy placed a small hand above the flask and closed his eyes in concentration.

He opened them. “Yes, it’s warmer!”

A sea of pink hands extended over the flasks. “Oh yeah!” the boys murmured in appreciation. “It was a chemical reaction!” Science Bob nodded in agreement.

“And where did the oxygen go?”

“The bubbles!”

“And what kind of reaction did we create, if we made heat?”


If only all science could be this fun.

He may have a flashy teaching and demonstration style, but in person, Science Bob is subdued, thoughtful, and restrained.

He does not aim to win the National Medal of Science, nor does he plan on curing cancer. His goals are much simpler.

“I want kids to be scientifically literate,” he said. “Kids don’t make model rockets anymore. Kids see videos online, and it’s hard to tell what’s real and what’s not. I want kids to question things.”

Science Bob said he wants to encourage children to analyze the things they see in movies, like exploding Star Wars rocket ships (can’t happen without oxygen), or Sandra Bullock being unable to hold on to George Clooney’s tether in Gravity. (She totally could have, he said, because there’s no gravity, duh.)

Once kids start questioning things, the magic of science becomes real, Science Bob said.

“We’ll put on gloves, and take the microscopes outside,” he said. Then, the boys will catch snowflakes. “I’ll get to watch the kids see that snowflakes really do have six sides for the first time.” Science Bob smiled. “You can’t do that in LA.”

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