This article is the first in a series on the most difficult classes to teach at Cornell.
Every year, the class begins with a bang. Literally. This year, the bang came in a simple enough guise: a balloon filled with hydrogen to the point that it burst.
As flame came in contact with the balloon’s plastic skin, fire and sound erupted. The explosion heralded the start of General Chemistry — CHEM 2070 — and it was loud, bright and visible. But what was harder to see was the sheer amount time, energy and money invested to put on such a class.
The rest of the lecture was more mundane. Prof. Hector Abruña, chemistry, looked through the syllabus, highlighting the dates of prelims, homeworks and laboratory experiments.
“Every hour of lecture takes about eight hours of preparation,” Abruña said.
Abruña, despite teaching at Cornell for the past 29 years, last taught the class in the mid-1990s. This semester, he is co-teaching the class with Prof. David Zax, chemistry.
“It’s a fun class to teach, but it takes an enormous amount of time and energy,” he said. “Early on, it’s exhausting because you are trying to prepare lectures ahead. But I think it’s our most important course because in it, we are most exposed as a department.”
Every year, about 900 students take the class. This year is no exception: 904 students, split across two lectures, are piled into Baker 200.
As a whole, the chemistry department teaches about 6,000 undergraduates each year, according to Linda Glaser, staff writer for the College of Arts and Sciences.
The biggest challenge of teaching General Chemistry, professors said, is scheduling the lab sections. Each lab section can have 22 students at most.
Prof. Barbara Baird Ph.D. ’79, chair of the Department of Chemistry and Chemical Biology, said the logistics are sometimes difficult to navigate.
“We have to work very hard to serve the students to get them into the classes they want to be in,” Baird said.
The administrative process begins in the fall. Chemistry professors are polled to discover who will leave for sabbatical the following year and to see who has any particular teaching preferences. In the spring, the professors are shuffled around until all teaching spots are filled.
New freshmen comprise the majority of the class. Teaching freshmen, according to Zax, comes with its own peculiar difficulties.
“Freshmen are often more enthusiastic, but they are also more easily frustrated and often have less of a sense as to how things get done,” Zax said in reference to enrolling for classes.
For incoming freshmen, the process begins in the summer.
“Over the summer, incoming freshmen make decisions about the courses they want to take,” Baird said. “This gives us a starting number to work with in determining the number of laboratory sections that will need to establish.”
This initial set of numbers is typically, however, an underestimation.
“A sizable number of students don’t pre-enroll. Other students change their minds after they get here,” Baird said. “This includes whether they will take freshman chemistry and which of the options they will take. We usually come close prior to the start of the semester, but we are not able to determine the final number of lab sections until students actually show up for class.”
New hires — who are frequently brought on in the spring — complicate the process, since the chemistry department tries to rotate its professors to ensure that no professor teaches the same class for more than three consecutive years.
Zax, however, has been teaching General Chemistry for three of the past four years. This semester, Abruña is teaching the first half of the course, while Zax will teach the second half.
Zax, like Abruña, spends multiple hours preparing for each hour of lecture.
“For each lecture, I look at the book and see what the book did well and what the book did poorly. I look for places where the text has done a weaker job than I think is appropriate,” Zax said. “Then I ask myself, how do I make it a little more concrete?”
Abruña also attempts to make the material more relatable, he said.
“I try to connect what I teach with physical reality and everyday experiences, so it becomes a little more real to them,” he said. “I also try to interject little vignettes, in my particular case dealing with energy and energy related fields because that’s what I am familiar with. For example, when we burned the hydrogen balloon, I used that as a teaching moment to talk about fuel cells.”
But, at the end of the day, an explosion is loud and attention-grabbing.
“Sometime over the past five to 10 years, Baker 200 got wireless. It’s fairly clear that some of the kids are not paying as much attention as they were,” Zax said. “Exploding something seems to help bring their attention back.”
A previous version of this story contained several errors. It inaccurately quoted Prof. Barbara Baird Ph.D. ’79, chemistry, as saying coordinating the logistics of the class, CHEM 2070, is almost impossible. In fact, she said it was a challenging, but manageable, task. The article also misquoted Prof. Hector Abruña, chemistry, as saying he is not eager to relive the process of teaching the class. In fact, Abruña did not say this. Additionally, the story incorrectly stated both the number of students taught by the chemistry department and the number of students allowed to enroll in lab sections for CHEM 2070. In fact, the department teaches 6,000 students per year, not 2,500, and each lab section can have 22 students, not 20.