Sciences, unite! Integrated intro course revolutionizes science instruction

Jan. 16, 2018 noon

At many colleges, students who are interested in science will enroll in multiple introductory courses, learning about genetics and chemistry and physics and computer programming as separate and largely unrelated disciplines. At Princeton, students have another option: the Integrated Science Curriculum (ISC). Four courses co-taught by multiple professors make up the integrated science curriculum — two classes in the fall, two in the spring.

“The labs have really been comprehensive,” said first-year student Bianca Swidler. “I feel like there’s been a great coverage of chemistry, physics, biology — it’s really hard to pick a favorite, like picking a favorite kid.” The photos below show ISC classroom and laboratory sessions. Each lab is spread across two weeks, to allow students time to learn new techniques and become comfortable applying them to research questions. Everyone pictured is a first-year student unless otherwise noted.

Lab 1: Reynolds numbers

Students drop spheres through clear liquids — a thick glycerin the first week, then water the second week — to measure the spheres’ falling speeds and calculate the Reynolds number of each fluid, a measure of its inertia and viscosity. In addition to introducing students to lab materials and techniques, the lab gives students an intuitive sense of how bacteria move through their thick, wet world. When students drop low-density aluminum balls through glycerin, the slow movement can be measured with just a ruler and a stopwatch. The students also use a motion-capture camera connected to lab computers to track the spheres’ descent from one frame to the next. The first week, they compare the computer-assisted measurements against those taken by hand. By the second week, when they drop steel balls through water, students depend on the camera and computer, as the dense beads fall quickly.

  • Students looking at computer in lab

    Artem Khan (left) and Kennedy Miller gather data from the motion-capture camera (far right) trained on a beaker of glycerin.

  • Students at computers in lab

    Students work in pairs to measure the slow progress of aluminum balls through glycerin, a proxy for the slow movement of bacteria through their moist environments.

  • Professor Callan giving Integrated Science lecture to students

    Professor Curtis Callan, the James S. McDonnell Distinguished University Professor of Physics, explains the ideal gas law through prescription sunglasses. “It was fabulous — like ISC meets 007,” said Swidler.

  • Student writing in notebook

    A student records careful measurements in a lab notebook.

Lab 2: Electronics and solar power

During the first week of this two-part lab, students gain a fundamental grasp of circuitry. As their skills progress, the challenges get harder. By the second week, students make a nanocrystalline solar cell and build a circuit that can redirect the solar energy once it crosses a predetermined threshold. “It’s combining a little bit of chemistry and solar-cell engineering with circuitry and the physics behind that,” said Jennifer Gadd, a lecturer in chemistry and the Lewis-Sigler Institute for Integrative Genomics (LSI) who has been an ISC lab instructor for five years.

  • Students working on circuit boards

    Kennedy Miller (left) and Bianca Swidler install a voltage divider on their breadboard.

  • Students working with graduate student on circuit board

    Teaching assistant Hugh Wilson (a graduate student in the Lewis-Sigler Institute for Integrative Genomics, standing) helps Jasper Lee (left) and Artem Khan learn how to debug their circuit.

  • Student working on circuit board

    Jasper Lee installs a potentiometer — a tunable resistor.

  • Students working on circuit boards

    From left: Noam Miller, Donovan Cassidy-Nolan and John McEnany measure the output from their breadboard.

Lab 3: Fluorescent E. coli

In their first biology-focused lab, students examine the relationship between DNA (genes) and gene expression. They are given five “mystery samples” of E. coli bacteria, four of which carry the genetic instructions to produce mCherry, a fluorescent protein. As they work to identify their mystery samples, students must isolate DNA, run polymerase chain reactions (PCRs) to amplify the number of specific DNA segments, and use a fluorescent microscope.

  • Students looking at beaker of liquid

    From left: Yechen Hu, Rohin McIntosh, Henry Harrigan and Isabel Medlock look at one of their five mystery samples in a cell culture flask.

  • Student working with microscope

    Students put samples into a microcentrifuge to separate out the DNA from the rest of the cellular material.

  • Student using syringe, student examining tube

    Daniel Jubas examines one sample while Katie Tam uses a micropipette to prepare another for PCR amplification.

  • Students watching microscope demonstration in lab

    Lab co-instructor Jennifer Gadd demonstrates how a fluorescent microscope can help determine whether mCherry DNA is present in a sample.

  • Student putting liquid into tube in lab

    Artem Khan prepares to separate out DNA from one of the five mystery samples of E. coli given to each team of students.

  • Liquid dropping from syringe, with glass beakers in background

    One of these five identical-looking samples contains wildtype E. coli, while the other four have mCherry DNA, which causes the bacteria to glow.

  • Student at computer with green light coming from microscope

    Donovan Cassidy-Nolan examines data from the fluorescent microscope.

  • Details from slide of E Coli experiment

    This phase contrast image of E. coli, taken with a microscope, will be paired with an image of the sample’s fluorescence to help identify the presence of mCherry DNA.


“A number of us at Princeton believe that some of the most exciting science of the future will take place at the boundaries between the traditional scientific disciplines,” said Joshua Shaevitz, a professor of physics and LSI, who is one of the curriculum’s several professors. “We hope to train a new generation of young scientists who naturally bridge these topics, feeling equally at home deriving equations, working with living cells at the bench and programming sophisticated computer analysis algorithms.”

He added: “Conventional introductory science classes can obscure the connections between fields by using different language and symbols for the same quantities or concepts. Integrated science is our attempt to teach a comprehensive introduction to the scientific endeavor that stresses the links between disciplines in a mathematically rigorous way.”

The curriculum was first imagined about 15 years ago, when several faculty members got together to create a cohesive introduction to the natural sciences. “Part of the idea was, ‘How can we convey the depths of the different subjects while encouraging the students to see their potential, in the broadest possible terms?’” said William Bialek, the John Archibald Wheeler/Battelle Professor in Physics and LSI, one of the creators of the integrated curriculum. “If you wait too long to introduce students to that way of thinking, you make their job more difficult, and you make our job more difficult.”

By the end of the integrated science curriculum, the students have received an unusually thorough preparation, said co-instructor Quan Wang, an associate research scholar at LSI and lecturer in physics and LSI who has also taught at Stanford University and the University of New Mexico.

“Last year, one of the students from this class ended up working in my lab,” Wang said. “It was really amazing to see a freshman who had developed so many skills just from this class that are directly integrate-able into modern-day research. It was something I’ve never seen before.”