Past topics


Monday, November 9, 2015
Going Wild in the City: The Evolution of Attitudes Toward Urban Evolution
Featuring Karen Snetselaar, Professor of Biology at Saint Joseph’s University

Several hundred years ago the wilderness was a frightening place where people might be banished to die alone, with no human support. The romantic idea of wilderness as a place where we go to get away from the cares of civilization is more recent and still prevails today. In neither of these very different views of wilderness is there a permanent place for people! And a conviction that wilderness (or true nature) can exist only without human interference has greatly influenced scientific investigations as well as vacation planning. Until quite recently, human-dominated ecosystems weren’t considered proper venues for mainstream ecology.

One can argue that serious challenges to this narrow view really began with the environmental movement of the 1960’s and 70’s, and it has become increasingly difficult to claim that there are places on the planet not impacted by human activity. Urban ecology and related fields are now much more widely accepted as appropriate and important scientific disciplines. After a discussion of how we finally got here, we’ll consider how this is changing our view of urban environments and leading to increased respect for the wild things found there.

Monday, October 12, 2015
Cancer Science: The Quest for a Cure
Featuring Pat Morin, Senior Director of Scientific Review and Grants Administration at the American Association of Cancer Research

Cancer.  It’s only one word, yet we now know it represents more than 200 diseases.  In 1907, it was a death sentence.  In that year, 11 physicians and scientists came up with a novel idea to collaborate to prevent and cure cancer.  They established the American Association for Cancer Research (AACR), which is headquartered right here in Philadelphia.

Today, we are still on a quest for that cure.  So much progress has occurred, yet nearly 600,000 Americans still die from cancer each year.  Join this month’s Science on Tap to learn about cancer science history, the trials and tribulations of scientific promise and failure.  And hear about today’s latest advancements in personalized medicine and immunotherapy.  There has never been a more exciting time in cancer research and treatment.  Pat Morin, PhD, of the AACR will explain, in simple terms, the current state of cancer research, and will highlight the latest and greatest in our quest to identify cures for this insidious disease.

Monday, July 13, 2015
The History of the Chemical Elements for (Big) Kids
Featuring Adrian Dingle, chemistry educator, author, and 2015 Société de Chimie Industrielle Fellow at the Chemical Heritage Foundation

The National Science Education Standards says that “The natural and designed world is complex; it is too large and complicated to investigate and comprehend all at once. Scientists and students learn to define small portions for the convenience of investigation… referred to as ‘systems’.” We know that the periodic table is one such system, but the methods for teaching it range from rote memorization to endless rounds of flashcards to chanting the elements call-and-response style. School is out, so what better time to think of a fun way to teach this concept? Join CHF Fellow, Adrian Dingle, as he talks about his most recent project, a children’s book about the history of the chemical elements. Learn a few fascinating facts behind the discovery of some of the elements, all delivered from an easy to follow kids perspective – oh, and with beer, too!

Monday, June 8, 2015
Join the DarkSide: Dark Matter Matters
Featuring Christina Love, Assistant Teaching Professor in the Department of Physics at Drexel University

Dark matter makes up over 80% of all the matter in the universe. We don’t know what it is. We can indirectly see dark matter by the gravity that it produces, but we have yet to directly detect it. There are three ways that researchers are currently looking for dark matter: particle detectors, particle accelerators, and excess particles.

Monday, May 11, 2015
Why We (and Weebles) Wobble but Don’t Fall Down
Featuring Tonia Hsieh, Assistant Professor of Biology at Temple University.

As you traverse the hazard-filled streets of Philadelphia on a daily basis, have you ever had to think about how you will step on and off a sidewalk, dexterously avoid a pothole, or simply stay upright and not fall down while walking? Though it might seem automatic to you, it turns out that moving through our natural and built environments is no easy feat. Movement is something that all animals do, and often in amazingly acrobatic ways. Ask a robot to do it, however, and it will often struggle and fall over the simplest obstacles. This talk will reveal some mysteries of animal locomotion that allow us to move through the world with grace and composure (most of the time). It will also show how integrating biology into robotics is enabling ever deeper insights into both biology and robotic design.

Monday, April 13, 2015
The Lost World of Plant Monsters: Animal-Plants, Stone-Plants, and Other Categorical Challenges
Featuring Lynnette Regouby, Mellon Post-Doctoral Fellow at the American Philosophical Society Museum.

Stone-Plants. Animal-Plants. Sensitive Plants. Eighteenth-century natural history was populated with categories that we no longer recognize but that at the time presented serious challenges to classification. This talk revisits a world of plant monsters, whose ability to walk, to feed, or to feel, breeched the boundaries between animal and vegetable kingdoms and helped to revise what it means to be a plant, a human, or something in between.

Monday, March 9, 2015
Shots for Spots and Want-It-Nots: Measles, Measles Vaccine, and Refusers
Featuring Karie Youngdahl, Director of the History of Vaccines project.

The recent measles outbreak stemming from exposures at Disneyland has focused attention on this disease that was eliminated from the United States in 2000. Karie Youngdahl, director of the History of Vaccines project, will put the current outbreak in historical context by looking at the epidemiology of measles over time and attempts at immunizing for measles from the mid-1700s. She will also discuss resistance to vaccination and the ways that arguments against vaccine have been made by anti-vaccinators from Edward Jenner’s time to now.

Monday, February 9, 2015
Guano Happens: A Illustrated History of Fertilizers in America.
Featuring Timothy Johnson, the Allington Dissertation Fellow at the Chemical Heritage Foundation for 2014-15 and a Ph.D. candidate in history at the University of Georgia.

In late summer 2014, some 400,000 residents of Toledo, Ohio lost access to tap water because of a massive bloom of toxic cyanobacteria in Lake Erie.  Every summer, similar events occur in watersheds that drain regions where soils are saturated with chemical fertilizers on farms and lawns.  If humans are responsible for this annual toxic tide, why has it been so hard to stop it?  In this talk, Timothy Johnson will discuss the environmental history of chemical fertilizers in the United States, exploring topics as diverse as guano islands, explosives production, and comic books to show how fertilizers became an indispensable tool for farmers, in spite of the considerable costs they have incurred.

Monday, January 12, 2015
The Floor is Lava (Literally): The Do’s and Don’ts of Volcanology
Featuring Loÿc Vanderkluysen, Ph.D., Assistant Professor, Department of Biodiversity, Earth & Environmental Science, Drexel University

Every year, an average of 60 volcanoes erupt worldwide; approximately 15 of these eruptions have the potential to disrupt air traffic and cause widespread destruction. The practical consequences of these damaging effects made front-page news in 2010, following the eruptions of Eyjafjallajökull volcano in Iceland (which caused extensive air traffic disruptions and flight cancellations), and Merapi volcano in Indonesia (during which 353 people were killed, and 350,000 were displaced). These events highlighted the need for novel and improved real-time volcano monitoring tools. In this presentation, Dr Vanderkluysen will talk about current eruptions in Hawaii and elsewhere across the globe, recent technological developments in volcano monitoring, and volcanic surveillance in the United States.


Monday, December 8, 2014
The Physics of the Perfect French Fry
Featuring Scott Paulson, Ph.D., Associate Professor in the Department of Physics and Astronomy at James Madison University

We’ve been enjoying french fries for centuries, yet they continue to elude home chefs and gourmands alike. Can science explain the art of perfecting this everyday food? Dr. Scott Paulson, french fry-enthusiast and physics and astronomy professor at James Madison University, says yes. During this Science on Tap, Paulson will explore the science behind the seemingly simple act of deep-frying a potato, including important questions such as: What variety of potato works best? Does the type of oil matter? Is fresher better? He will also discuss high-heat vs. low-heat cooking techniques and the reluctant interaction of oil with water, in a quest to uncover the perfect french fry recipe.
View the presentation slides.

Monday, November 10, 2014
Do Cats Make You Crazy?
Featuring Omar Harb, Ph.D., Education and Scientific Outreach manager for the Eukaryotic Pathogen Databases

The 2014 Ig Nobel prize in public health was recently awarded to researchers studying whether owning a cat is mentally hazardous to people. The source of this hazard is not the cat itself but what it can carry: an extremely contagious and ubiquitous parasite calledToxoplasma gondii. This successful parasite can infect almost any warm-blooded animal, hiding in the brain as a cyst. In most people it is thought that the dormant Toxoplasma brain cyst does nothing. However, research suggests that these dormant cysts may actually have neurological consequences. Before you run home and get rid of your cuddly kitten, we will objectively take a look at the research to try and understand if cats really make you crazy.

Monday, October 13, 2014
Thinking Outside the Jar: Exploring the Neurophysiology of Creative Genius
Featuring Seth “Dr. Adventure!” Kane, owner, Lead Fabricator, the New Flesh Workshop

Examination of Albert Einsteins brain, provided by the Mütter Museum under a Wood Fellowship grant, yielded evidence of cell growth up until his death. How did he foster this growth? What about his life and methods led to these changes in physiology? This month’s talk focuses on how joy, imagination and diligent mental exercise contribute to physiological changes in the brain, optimizing it for creativity.

Monday, September 8, 2014
Permaculture Food Forests in the City
Featuring Phil Forsyth, urban orchardist and Director of the Philadelphia Orchard Project

When William Penn created Philadelphia he envisioned a lush American Eden, a “greene country towne.” Today,  Philadelphia is a far cry from that vision, but there is a growing movement to create a healthier, more sustainable city full of green spaces with access to healthy local food.

Phil Forsyth, Philadelphia’s own Johnny Appleseed, has planted dozens of permaculture orchards and edible forests through his work with the Philadelphia Orchard Project. He will discuss permaculture, a design science aimed at creating sustainable regenerative landscapes and communities, and food forests, a permaculture strategy for developing diverse, multi-layered food-producing ecosystems. Phil believes we can we create functioning, diverse environments within the city that that mimic the natural systems within forests. These food forests and orchards bring fresh fruit to Philadelphians, replace vacant lots, bring the community together and help clean the water and air.

Monday, August 11, 2014
Show and Tell

Featuring Bartram’s Garden, Eastern State Penitentiary, Elfreth’s Alley, Free Library of Philadelphia, Independence Seaport Museum, National Liberty Museum, National Constitution Center, University of Pennsylvania Museum of Anthropology & Archaeology

How do some of Philadelphia’s great historical and cultural institutions relate to science? Find out at a special format Science on Tap: Show-and-Tell event! Join us as Philadelphia museums bring a piece of their story to National Mechanics to demonstrate to us how their work relates to science.These organizations will present a specific object or idea in flash talk format, giving you a chance to see these establishments in a new scientific light.

Monday, July 14, 2014
Alien-like Catfish
Featuring ichthyologist John Lundberg

Want to know what’s in the water? Ask John Lundberg, PhD, about his recent research. Kryptoglanis shajii is a strange fish—and the closer scientists look, the stranger it gets. This small subterranean catfish sees the light of day and human observers only rarely, when it turns up in springs, wells, and flooded rice paddies in the Western Ghats mountain region of Kerala, India.

Lundberg, one of the world’s leading authorities on catfishes, started taking a closer look at several specimens soon after the catfish’s discovery in 2011. It’s quite puzzling, but it doesn’t seem to fit into the family tree of catfishes.

John Lundberg is an ichthyologist, evolutionary biologist, and systematist. His research mainly concerns fish diversity and diversification using modern and fossil specimens and phenotypic and genetic data. He is drawn to exploration and collecting in poorly known waters and fossiliferous sediments. Lundberg joined the Academy of Natural Sciences as the curator of ichthyology, where he oversaw, grew, and promoted one of the world’s largest and most active research collections of fishes. He retired in 2013 but remains active in research.

Monday, June 9, 2014
The Men Behind the Screens: RCA and the Origins of the LCD
Featuring CHF Research Fellow Ben Gross, PhD

Everyone has heard about liquid crystal displays. These thin electronic screens are found in our televisions, laptops, and smartphones. We rely on them to consume information and communicate with each other.

But what exactly are liquid crystals? Who figured out they could be used in displays? And why did RCA—the company that oversaw their invention—never succeed in commercializing them? In this talk Ben Gross will provide a “behind the screens” tour of the science and history of the LCD.

Ben Gross is a research fellow in the Chemical Heritage Foundation’s Center for Contemporary History and Policy, where he oversees a variety of projects related to material innovation. He also serves as curator of “Innovations That Changed the World,” an exhibition on RCA’s contributions to the history of electronics at The College of New Jersey. Gross earned a Ph.D. in the history of science from Princeton University and is currently revising his doctoral dissertation on the development of the LCD for publication.

Monday, May 12, 2014
Some Questions to Ask Ben Franklin

Featuring  professor and APS Executive Officer Keith Thomson

Benjamin Franklin’s most famous experiment supposedly involved a kite and a key. But what was it for? Did he actually do it? In fact, could he have done it? Alternatively, why are some authors so keen to suggest it is all a fake?
Keith Thomson is Executive Officer of the American Philosophical Society and Professor Emeritus of natural history at the University of Oxford. He previously taught for many years at Yale and was President of the Academy of Natural Sciences of Philadelphia. He is the author of 12 books including The Young Charles Darwin (2009) and Jefferson’s Shadow: the Story of his Science (2012).

Monday, April 14, 2014
Culturing Food: History, Health and Fermentation
by Adam D. Zolkover

What do The Epic of Gilgamesh, James Cook’s Voyage Toward the South Pole and Round the World, the dairies of Gruyères Switzerland, and our speaker’s home kitchen all have in common?  Fermentation!

We can define fermentation as a biological process:  as the metabolization of sugars by yeasts, bacteria, and sometimes our own cells, into gases, acids, and alcohol.  For denizens of the microbial world, it’s a matter of eat, then excrete.  But for humans, fermentation is a cultural process.  Bread, beer, dairy, pickles, and preserved meats have all been key ingredients in the success of agricultural, sedentary, urban societies.  And they have all been essential to long voyages of exploration.

This talk explores the intermingling of science and history in the kitchen.  And it explores some of the practical aspects of fermentation for home cooks today.

Adam D. Zolkover is a folklorist, freelance writer, and food blogger living in Philadelphia, PA.  He serves as editor of the Institute for Civility in Government’s online initiative — The Civility Blog — and teaches courses in folklore, literature, and popular culture at Philadelphia University, Temple University, and The University of Pennsylvania.  He has run workshops on fermentation and lacto-pickling for the Mount Airy Learning Tree.  And he is owner and proprietor of, where he writes about food culture, sustainable cooking, and the preparation and consumption of all manners of delicious fermented things.

MONDAY, March 10, 2014
Rare Earth Metals: iPhones to Alien Life
Featuring Dr. Eric Schelter, Department of Chemistry, University of Pennsylvania

Banished to the bottom of the periodic table, the rare earth metals are rarely discussed, exotic curiosities. Yet these metals are hidden throughout our daily lives, enabling internet communication, harvesting wind energy, and illuminating our existence. We’ll discuss the intersection of the metals with clean energy and the dark side of their exploitative mining and processing. From magnets to volcanic mudpots, rare earth metals inspire and amaze.

Eric Schelter is an assistant professor of chemistry at Penn. His area of specialty is f-block chemistry, and his work currently focuses on the chemistry of rare earth elements. 

Monday, February 10, 2014
Next Generation Paleontology
Featuring Ken Lacovara, PhD, Department of Biodiversity, Earth & Environmental Science, Drexel University

 According to Dr. Kenneth Lacovara, “technology in paleontology hasn’t     changed much in about 150 years. We use shovels and pickaxes and burlap and plaster. It hasn’t changed—until right now.”

Lacovara and a team of researchers at Drexel University are bringing the latest technological advancements in 3-D scanning and printing to the study of ancient life. Using scale models of real fossils, for the first time they will be able to test hypotheses about how dinosaurs and other prehistoric animals moved and lived in their environments.

 Ken Lacovara, associate professor in the Department of Biodiversity, Earth and Environmental Science at Drexel University, focuses on Mesozoic Era paleoenvironments that contain the remains of dinosaurs and other vertebrates.  He co-authored descriptions of two new dinosaurs (Paralititan and Suzhousaurus) and is about to unveil the remains of a new giant, a 70-ton titanosaur from Patagonia.

Monday, January 13, 2014
“What’s the Matter with the Higgs Bozon”
Featuring Dave Goldberg, PhD, Professor, Department of Physics, Drexel University

The Higgs boson is one of the biggest, most influential discoveries of the last decade, important enough that it resulted in an almost instant Nobel prize.  But what’s it all about? How does it work? And what does it mean for a particle to “create mass”? If you’ve been feeling confused at cocktail parties, Dave Goldberg will give you a half hour primer on how the universe works to set you straight.

Dave Goldberg is a theoretical cosmologist and professor of Physics at Drexel University.  He is the author, most recently, of “The Universe in the Rearview Mirror: How Hidden Symmetries Shape Reality.” Dr. Goldberg is interested in the interface between science and pop culture and is especially prone to nerdly excess of sci-fi references.  He writes a regular “Ask a Physicist” column for, has been featured on WNYC’s Studio 360, The Leonard Lopate Show, WHYY’s NewsWorks Tonight and has contributed to Slate, Wired & the L.A. Times.