Students in most science classes at Hostos bring a wide range of experiences, interests, and pre-requisite skill levels. Faculty, therefore, have to teach the foundations of scientific knowledge and scientific inquiry to a student body with different levels of preparation (Stayer, 2007). Although there is plenty of literature on teaching strategies, among them jigsaw technique, gallery walk, concept sketch, role playing to name some (Tewksbury, 2005), not many of these widely-used strategies are easily applicable to fields where knowledge builds upon previous knowledge. In teaching foundational courses it is especially important that basic concepts are fully understood. Therefore, instructors have to explore strategies that will improve the delivery of concepts and to enhance student learning. My experience teaching in introductory biology for several years had been a colossal adventure with mixed outcomes.
This article describes one of the teaching strategies I designed for general biology laboratory sessions. General Biology is a course that contains copious material which has been divided into fourteen labs. Some are too ample to cover in a single session. I solved the dilemma of reducing content or cutting portions of the experience by organizing working groups. These working groups are organized randomly to allow students to acquire lab skills, follow procedures and teach each other. Each group is responsible for a portion of the lab content, which could be a particular step in a procedure or an entire technique. Groups are responsible for reviewing protocols, learning the procedure, conducting the practical part and explaining their work and results to the class.
The goals of this collaborative group work in introductory biology laboratory are intended to improve student learning and retention, and to build up general education skills such as analytical thinking, collaborative work, and oral communication.
Labs are ideal for conducting group work because their settings are more relaxing than the environments of typical lecture rooms. Students are allowed to interact with their classmates and move from one place to another. Lab benches facilitate group formation with four to six per group facing each other.
The model described in this article is a practice conducted in the lab on organic molecules (this methodology is also applied in diffusion and osmosis, photo- synthesis, and DNA extraction lab experiences). The objectives of the laboratory are to learn to perform various tests to detect the presence of proteins, simple sugars, starch, and lipids. Students are introduced to the theoretical concept during lecture and review the same topic during the first portion of the lab. After the topic has been revisited the instructor highlights the parameters of the experience (see Figure 1).
The class is divided into four groups of 4-5 students. Each work group is assigned one technique to learn. Simultaneously, all the groups begin by reading the protocol in their lab manuals. With the help of the instructor they conduct the experiment and learn to interpret the results. Group members interact with each other, they read and re-read the procedure, and check the list to select the correct materials and chemical solutions. They distribute tasks such as gathering lab materials, measuring and adding solutions, making observations, taking notes, collecting data, analyzing data, interpreting results, and drawing conclusions. The first part of the lab experience is completed after the instructor has visited each group to ensure that directions have been followed and to listen to the oral report of the student who has been selected as the speaker for the group. The instructor provides feedback, ask questions and makes necessary corrections. The group reviews the protocol until each member understands the technique.
After a short interval each member of the group is ready to explain experience to their classmates. Groups break down and students visit each one of the four “stations” independently. Members of each group take turns to explain the procedure to every visitor while the rest visit other stations. At least one student is required to remain at the station while his/her partners obtain information from other groups. They all collect information, and ask questions to the presenter in order to get the correct information for their lab report. The reports must contain detailed information of all four experiments.
After the teaching and sharing period, and assuming that each student has learned the details of each procedure, the groups are ready to test their newly acquired ability by using the four techniques to test food samples. Each group receives a sample, cookies, eggs, chips, cereal, or any other familiar product. After a brief discussion, the group agrees in a hypothesis and proceeds to run the four tests. The sample extract is separated into four test tubes, each tube is tested for one of the organic molecules under study. The instructor creates a blank chart on the board and invites the groups to record their results. Once the chart is completed students interpret results and write conclusions.
Each student is required to write a laboratory report for the following week. The report must follow the structure of a biology lab report, including introduction, objectives, materials, procedure, results, and conclusions. Although the number of pages is not established, most reports contain between 5-8 pages. Reports contain the description of each one of the four techniques, illustrations or digital images of the experiments and tables. Some students comment on the activity or a particular procedure: “the method used to separate each test per group was valuable because we were on the knowledgeable side when we have to explain our test”; others realized the need to be more inquisitive: “I would have asked more informative questions to help me compose a better lab report”; while others thought the experience as a whole was beneficial: “overall the lab experiments were very engaging and interactive”
This is a highly interactive experience. It allows learners to retain scientific knowledge and apply it to understand a recognizable factor. It allows the development of problem-solving skills by means of exploration beyond the common boundaries of instructor assistance. It leaves room for interaction, practice of note-taking and oral communication skills.
The interaction is lively and enthusiastic. The instructor walks among the benches to ensure everybody is participating and provides suggestions. Students act as masters of their technique while visitors are relentless questioners because they are entitled to get the correct information to prepare their reports. The happiest group is the group that performs the test on to detect reducing sugars because they get to use a hot plate and the chemical reactions are colorful; the unhappiest group is the lipid group because the differences between positive and negative reactions are strikingly different.
Overall, this group work experience has been rewarding. I apply the same strategy in other lab topics. The only downside is the limitation on materials. Ideally each student could benefit from handling his/her own material, but this limitation has not diminished the level of satisfaction of the class. The amount of lab materials used by the groups generates lots of dirty glassware and the benches need extra cleaning time, but this has never been a cause of dissatisfaction among the students.
Staver, J. (2007) Teaching Science. International Academy of Education. http:// www.ibe.unesco.org/publications/EducationalPracticesSeriesPdf/Practice_17.pdf (retrieved Jan 05, 2011) .
Tewksbury B. and H. Macdonald (2005) Designing Effective and Innovative Courses: On-line Course Design Tutorial. http://serc.carleton.edu/ NAGTWorkshops/coursedesign/tutorial/strategies.html (retrieved Jan 05, 2011).