Under the Microscope

The following article by Upper School Science Teacher Dan Fortney appears in the summer 2014 issue of Saint David's Magazine:

Scientific inquiry is the diverse way in which scientists study the natural world and propose explanations based on the evidence derived from their work. Scientific inquiry also refers to the activities through which students develop knowledge and understanding of scientific ideas, as well as an understanding of how scientists study the natural world. It is a powerful way of understanding science content in which students learn how to ask questions and use evidence to answer them. In the process of learning the strategies of scientific inquiry, students learn to conduct an investigation and collect evidence from a variety of sources, develop an explanation from the data, and communicate and defend their conclusions.

Scientific inquiry can best be accomplished by using the Five E instructional model. In the first phase, engage, the students are motivated to show interest in a subject. This can be done through an activity or experience that allows them to connect current and past experiences. After students are engaged, they move to the explore phase of this strategy. In this phase, students are involved in activities that help them think, problem solve, or investigate. The activities help students develop an understanding of a science concept, skill, or process.  

The next phase is to explain or formally present the scientific concept, process, or skill. The explanation phase connects students’ prior knowledge, observations, and findings from the explore phase. In phase four, students elaborate or apply information learned in the previous phases to new situations and ask such questions as: “What happens if . . . ?” or “Can I find a way to . . . ?” In the final phase, evaluate, students work with each other to check their understanding.

At Saint David’s, an outgrowth of our Curriculum Initiative has been to increase the opportunities for boys to engage in this type of learning. A prime example can be seen in our new partnership with Cold Spring Harbor Laboratory for a new Fifth Grade DNA Inquiry Unit. This partnership afforded the boys the opportunity to work closely with scientists at the DNA Learning Center (DNALC) and in our own science labs at Saint David’s. 

The DNA Learning Center—the world’s first science center devoted entirely to genetics education—is an operating unit of Cold Spring Harbor Laboratory, an important center for molecular genetics research. The Dolan DNALC, DNALC West, and Harlem DNA Lab extend the Laboratory’s traditional research and postgraduate education mission to the college, pre-college, and public levels.  The DNA Inquiry Unit consisted of three phases where the boys observed modeling of lab protocol, chose research questions, and worked in teams to create a mini presentation. Phase one gave boys the opportunity to work hands-on with compound microscopes, identify specimens within the kingdoms of biological classification, learn about the structure and function of cells, make a cell model, and extract DNA. These hands-on activities gave boys the opportunity to become engaged by and explore the properties of cells and DNA.

Also during phase one, the boys ventured to the DNA Learning Center in Cold Spring Harbor and the Harlem Lab to conduct experiments, work with sophisticated lab materials, and participate in a question-and-answer session with a scientist. During the visit to the DNALC, the boys worked with sophisticated lab equipment to solve a “DNA mystery.” They were given a sample of one plant that is known to have life-saving medicinal properties but is very hard to foster. They were also given three other plant samples and asked to determine, based on their extensive DNA analysis, which of the three was most closely related to the cure-all, and therefore, the most likely to share its medicinal properties. Working in pairs, each fifth grader practiced following the steps of a lab protocol to carefully isolate and extract DNA from the leaf sample, amplified the DNA using Polymerase Chain Reaction (PCR), loaded their DNA samples onto an electrophoresis gel, and then interpreted the results of the gel using ultraviolet light.

The boys also explored the learning center’s hands-on DNA exhibits and sat down for a symposium with research scientist Dr. Mona Spector, who has spent her career studying the ways cancer cells disrupt and change DNA sequences. The boys asked questions that were thoughtful and probing. It was most exciting for them to see how the science work done in a lab relates to real life issues and concerns and has the potential to do great things like identify cures for diseases.

During the visit to the Harlem Lab, the boys used microscopes to observe organisms that scientists

study to gain insights and a better understanding of the workings of the human body. Using the microscope, the boys examined the fruit fly and roundworm, which have DNA that is similar to humans. The boys looked at both normal and mutated samples of each organism, compared and contrasted the types of mutations, and discussed the implications to survival in the wild. 

After careful examination of the roundworms, the boys were able to observe not only mutations in shape but also the ways those mutations affected movement patterns of the worms, which were living. This investigation helped the boys to see how scientists must study what can go wrong with an organism’s genetic code in order to develop cures for diseases and other genetic abnormalities.

The second phase of the DNA inquiry unit allowed the boys to develop their choice of a research question, select a sample to study, and independently apply skills. This phase effectively enabled them to work like real scientists in the lab. The first opportunity occurred when the boys observed the morphology of varying types of fruits and vegetables. After careful observation of these items, the boys conducted a multi-step process that involved extracting and amplifying the DNA from their chosen fruit or vegetable and performing gel electrophoresis. The samples were sent to a facility for decoding, and the results returned to the boys for analysis.

In their culminating lab experience with the DNALC educators, the boys had the opportunity to refine their DNA fingerprinting skills and test their own research questions. Along with their teachers and the DNALC educators, the boys performed DNA extraction and gel electrophoresis on samples related to their research questions. Some of the questions included: How pure is chicken or seafood? Is spicy tuna really spicy tuna? What organisms might be present in pond water? How much DNA can be found on dollar bills? The boys exhibited a high level of enthusiasm and eagerness to see what their DNA samples would show and displayed great levels of proficiency and patience while following the detailed steps of the protocol.

The final phase of the unit involved the boys getting the results of their DNA samples and making presentations of those results, as well as demonstrating the many lab techniques and new material they learned during the unit. They presented their findings to fourth graders with poise and confidence and were eager to share what they had learned so much about this year.

Some of the presentations that involved DNA barcoding results were “Saint David’s lunch: is that REALLY chicken?” “Are your favorite burgers frauds?” and “What is in Central Park pond water?” The learning stations included “Take a spin on the centrifuge,” “What is DNA?” “DNA extraction,” and “Gel-electrophoresis.” The energy during the presentations was infectious, and showed a great understanding of the material learned over the course of the term.

This inquiry-based DNA unit encouraged and enhanced the natural curiosity and motivation the boys have for science, which in turn helped to connect science to the boys’ everyday life. Inquiry and inquiry-based strategies help students develop a deeper understanding of science and create new scientific discoveries.