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UIC TA Handbook - Teaching in a Laboratory Setting

Introduction

Laboratory TAs fulfill somewhat the same function as discussion leaders in other fields, but their duties are usually more well-defined. Lab instructors are responsible for performing experiments or demonstrations which are important companions illustrating the concepts presented in the large lecture sections. Students can learn and appreciate what is behind the "facts" they learn in the course lecture by having a positive experience in the lab­ oratory.

Learning during the laboratory period is usually accomplished via personal discovery, group discussion with other students, and small group interactions with the instructor. There is a tendency for students to view lab exercises as a tedious list of directions. By circulating through the lab and asking students conceptual and analytical questions, you can do a lot to overcome this view­ point. These question and answer periods, be they for­ mal or informal, are often the times when a student's understandings of the subject matter will increase.

Safety Procedures

Safety takes on special importance when you are directly responsible for the health and well-being of your laboratory students. Check your department 's orientation schedule for when laboratory emergency and safety procedures will be covered. If not listed, see your faculty advisor or lab coordinator for emergency and safety information.

Planning and Preparation

The best way to prepare for labs is to conduct the experiments or problems yourself with the students' lab manual in hand. You'll discover whether directions are clear and whether students have the skills necessary to complete the experiment. You'll know exactly the type and numbers of equipment to reserve. Jot down notes as you proceed so that you can estimate the amount of time the experiment will take, clarify confusing passages, and demonstrate new or difficult procedures. If you know in advance what to expect, what problems students are likely to encounter and what questions they will ask, you will be able to make much better use of your time in the lab itself.

Student Preparation

Students who have only a faint recollection of the lab's accompanying lecture may follow directions mindlessly, but those who have reviewed lecture notes and the lab manual will have some understanding of the experiment's importance. Devise some means to ensure that students are familiar with the lab before they come to class. Some instructors feel that grades on lab reports are incentive enough, while others require students to submit a statement of purpose and procedures or an explanation of why and how the experiment is relevant to the course. Students who have no understanding of why the experiment is important will derive very little knowledge from it.

Supervising the Experiment

At the beginning of the lab, review the purposes and procedures of the experiment. You might present information on how the experiment relates to current developments in the discipline, or discuss the students' statements of objectives. Ask for questions, clarify any ambiguities in the lab manual, and demonstrate special procedures rather than interrupt the experiment later.

Try to talk with each student at least once during the experiment. Technical and procedural matters can be handled quickly, but your primary role is to help students master the steps of scientific inquiry--recognizing and stating a problem so that it can be explored, data collected, a hypothesis formed and tested and a conclusion drawn.

There are a variety of ways to help students solve problems for themselves. Get students to work problems while "thinking out-loud." Encourage students to talk about what they are doing and why. This will slow down the thinking process and make it more explicit and more accurate. You can often help students check their own reasoning and find their own mistakes by having them verbally express exactly what they know about the problem. Comments or questions that can help students clarify their thinking might include some of the following:

  • What are some possible ways you might go about solving this problem?
  • Tell me what you know about the problem?
  • How might you break the problem into smaller steps?
  • Please tell me how you got from step one to step two?
  • What are you thinking right now?
  • I don't understand your reasoning behind that step. Will you please explain?

However you may approach this part of your task, refrain from giving outright answers or advice. If lab partners ask "Why can't we get this to come out right?" try asking a series of questions which lead them to discover the reasons for themselves rather than simply explaining why the experiment failed. Of course sometimes the reason will be relatively simple ("You used hydrochloric acid instead of nitric acid"), but just as often the reason will be more substantial -- a matter of timing, sequence, proportion, or interpretation. Perhaps the student has the necessary data but has overlooked an important step in analyzing the results or is unable to synthesize a solution.

It's very tempting to help students by giving them the answer but unless you resist that temptation, they are likely to falter at the same stage in the next experiment or problem. Students may become frustrated if they can't get a straight answer out of you, but they will learn more.

Evaluating Student's Performance in Labs

Much of the general advice on evaluating student performance applies to labs as well as to lectures and quiz or discussion sections: your methods of measuring student achievement should match your criteria and the course objectives. Written lab reports will probably be a source of information about the student's progress. If you talk with every student during every experiment, you will have a reasonably accurate idea of how students are progressing, but it is difficult to include your reasonably accurate idea in an objective evaluation. A student who gets the "wrong" result and determines why might have learned just as much as the student who gets the "right" result without knowing why.

If part of your responsibilities as a TA is grading, decide how you will evaluate student's performance during the semester. Attendance will count, perhaps, but also whether you will require written statements before every lab, and whether will you grade students on their progress throughout the semester or only on the final result as it appears in their written lab results.

Explain your policy to your students, so they will know what to expect. Keeping in mind that some will be more willing to experiment, explain that you will not penalize them for an incorrect answer--if there is a reasonable explanation of the incorrect result included in the final labor report.

References

Black, B. & Acitelli, L.K. (Eds.) (1991). A guidebook for University of Michigan teaching assistants. Ann Arbor, Ml: The Center for Research on Learning and Teaching, The University of Michigan.

Center for Teaching and Learning. (1991). Teaching at Carolina: A hand­ book for instructors. Chapel Hill, NC.: University of North Carolina

The Department of Medical Chemistry and Pharmacognosy, UIC College of Pharmacy.

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