III. Typical Teaching Situations

Laboratory Teaching

Introductory Chemistry lab with Fei Ding, an international TA.

As a laboratory instructor, you teach students how to learn by doing; at the same time, you motivate, teach, and encourage them individually. Because only a relatively small number of students can work in a lab setting at one time, you have the chance to interact closely with your students. You may also be responsible for grading their work, even in labs accompanying a lecture.
Although your role as a lab instructor will vary somewhat depending on your discipline, some general precepts apply. Above all, assume nothing. Your students come from widely varying backgrounds, many from schools with little or no scientific equipment. They need instruction in its use-yes, even the microscope-and they depend on you. This section offers hints for successful laboratory teaching; for basic information, see "Preparing a Course," "The First Day of Class," and "Specific TA Concerns;" for details about preparing lectures, see "Lecture Courses."

Preparing Labs

At the beginning of the semester:

• If your lab is part of a lecture course, attend the lecture so you can plan the corresponding lab work.
  
  
• Preview texts and lab manuals used in the lab and lecture. The course instructor should schedule meetings to discuss the course and lab.
  
  
• Find out where supplies are stored and who orders course materials.
  
  
• Give students the laboratory and safety rules in writing and verbally, and enforce them. If no departmental rules have been established, create necessary ones.

For each class meeting:

• Know the material thoroughly, including the theoretical basis and historical background for experiments or exercises to make them relevant to students.
  
  
• Compare the content of your lab to the lecture, deciding what information to reinforce and what to omit. Students tire quickly of frequently repeated background material.
  
  
• Practice with and test all equipment to make certain it functions properly before class. Know how to cope with equipment breakdowns.
  
  
• Complete all experiments and demonstrations at least once before class.
  
  
• Make certain all necessary materials are available in the right amount.
  
  
• Prepare lab notes, outlines, diagrams, and other necessary handouts.
  
  
• Write outlines, diagrams, illustrations, etc. on the board or overhead transparencies before class.

In the Lab

Start on time from the very first meeting; don't cancel the first lab, even if the syllabus does not schedule an experiment (see "The First Day of Class"). You may want to give a short (five- to ten-minute) quiz at the beginning of labs both to inspire punctuality and to focus students' attention immediately on the lab. With the right questions, you can also discover how well your students are prepared for lab.

You have to be more organized than you realize to teach labs.

— Javier Gonzalez, Chemistry

Lecturing. Introduce each lab by stating what you will be doing, how it fits into past and future work, and what the students should learn. In your short lab lecture, you will probably do the following:

• Announce the day's project, orally and/or on the board.
  
  
• Explain the task, perhaps by demonstrating samples you or former students have prepared. To heighten students' interest and help them remember, point out intriguing pertinent facts: for instance, during a Biology 204 lecture on fungi, the professor mentioned that a university administrator had died from eating a poisonous mushroom he had misidentified on Grounds.
  
  
• Furnish information students need to complete the lab activity. Prepare a handout, especially if you use drawings or diagrams, allowing room for students to add necessary details. Handouts help first- and second-year students learn to take notes and reduce the amount of time spent lecturing.
  
  
• Distribute materials to be used.

Throughout the lecture, you can remind yourself to invite students' questions by writing "Questions" in colored ink at appropriate transition spots in your notes. To promote students' thinking and verify understanding, write appropriate questions into your lecture. If your students are not accustomed to questions during a lecture, they may not answer until they become more familiar with this "new" method. Begin with who, what, when, where questions and progress to why questions. By the end of the semester, you will have a more lively class where actual learning-not just memorization-takes place.

I ask observational questions which guide students' thoughts to the right answer. In the end, the students have reasonably concluded the answers themselves, raising their confidence and enticing their minds to future explorations.

— Brian Silliman, Environmental Sciences

Supervising students' work. As students do their lab work, make yourself available. While building rapport and encouraging students, you can easily ask probing questions and correct faulty procedures. Call students by their names, using a seating chart at first if necessary. Move throughout the lab, watching for signs of students having difficulty: frustrated noises, confused expressions, flipping of text or lab manual pages. When individuals or groups have problems, inquire first: "What did you do first?" "When did you first have trouble?" "How else could you solve this dilemma?" Resist deciphering the problem for students; help them figure it out instead (see "Academic Difficulties").
Interrupt the entire class to make general remarks only when you find many students in the same predicament. When you do work with the class as a whole, get all students' attention before giving additional instructions. To explain experiment procedures, use the materials to show students directly rather than giving verbal instructions which may be confusing. Rephrase a student's question before answering so that everyone can hear it. Not only does this technique involve the whole class, it gives you a few moments to consider your response.

Summarizing. Finish the lab by reviewing what students should have learned and, if appropriate, previewing the work for the next class. Discuss any problematic parts of the lab so that the lesson plan can be adjusted for next year, if necessary.

Labs allow a teacher to be more creative than is possible during lecture. For instance, to illustrate the principles of optimal foraging for resources, I co-designed an exercise called Darwinopoly: students actively foraged for candy throughout the corridors of Gilmer Hall. They found that even humans exhibit a variety of foraging strategies which conform to the predictions of theory!

—Jennifer Secki-Shields, Biology

Visual Aids

Visual aids vary your presentation, help clarify the direction of your talk, and assist students who best learn visually: consider using the blackboard, overhead projector, slides, films, computer, video, and handouts. By following a few simple tips, even a novice lecturer can appear masterful:

• Plan and prepare your use of visual aids ahead of time, and consider using color to highlight important areas or ideas. Before class, make sure your presentation is large and legible by checking from the back of the room; remove any furniture or equipment that could distract students.
  
  
• If you use Power Point (or another presentation program) or write the outline or key information on the board or overhead transparency before class, you can refer or add to it as you speak. Computer programs allow you to keep your outlines for easy updating and changing. If you use these, however, be sure that their presence does not lead to such a speedy presentation that students cannot absorb material or take adequate notes.
  
  
• Slides, movies, and videotapes are forceful tools if you actively teach with them rather than using them as fillers. To prepare, preview programs and verify that slides are available and in the correct order. When using videotape, decide when you will pause and what questions or comments you will use. Tell students why you're showing the program and preview important points with them. Ask students to perform pertinent tasks during and after the presentation. For instance, can they find the main points or the bias of the documentary? Or, how are various geological formations similar?
  
  
• Remain at the front of the room and use a pointer, if necessary, to keep students' attention and to observe how well they are following.
  
  
• At the end of the presentation, review quickly, emphasizing important points.

In both the classroom and the lab I begin with the assumption that all students have some special talent, and I concern myself with trying to discern and foster it. Regardless of the course level, I expect students to have opinions, to think and learn independently, and to take an active role in defining their work.

—Cassandra Fraser, Chemistry