Center for Research on Learning and Teaching (CRLT) -- University of Michigan
Guidebook
for Teaching Labs for University of Michigan Graduate Student Instructors
by Beverly Black, Martha Gach, and Nancy Kotzian
Laboratory classes present a special challenge for the graduate student instructor. You must help students master physical techniques as well as new modes of thinking, all in a relatively brief period of time. The relaxed classroom atmosphere that is typical of most labs encourages free exchange of ideas among students. In some labs, students are encouraged or required to work collaboratively in groups, which you will facilitate.
This guidebook was written to help you as you begin teaching in a laboratory setting. The presence of laboratory classes in many departments throughout the University of Michigan has required that the material be targeted to a general audience. At present, it includes sections on goals of laboratory classes, the roles of a lab GSI, preparing for and teaching a lab class, helping students work collaboratively, and grading. The Guidebook is currently under development and we welcome any and all suggestions for improvement.
Note: If this Guidebook overlaps or counters specific information provided by your department for the lab you teach, use lab-specific information.
Many of the ideas in this Guidebook came from notes prepared by David O'Connor (Nuclear Engineering GSI) and Chuck Anderson (Physics GSI) for the workshop "Teaching Labs" conducted by them during the CRLT Teaching Orientation for new GSIs, September 1993.
The original edition of the Guidebook was conceived and developed in association with the College of Literature, Science & the Arts Teaching Assistant Development Program.
© July, 1996
Every lab class has goals that may be particular to that course and it is important to find out those goals before classes begin. A general goal that usually pertains to most labs is to make a connection and understanding between the theoretical elements of a discipline and the practical aspects of the technical performance. In general, there are three objectives which should be considered when teaching a lab. First is the practice and mastery of specific technical skills such as using the microscope, preparing an agar plate or setting up an apparatus for measuring weight changes. Second is the mastery of the skills of the scientific process such as observation, classification, inference, hypothesizing, and designing methods of investigation. The third objective is that of experiencing abstract concepts in a concrete manner, such as measuring and understanding free energy or angular momentum (Gale and Andrews, 1989).
On another level the lab experience is valuable for its ability to give students a more intimate knowledge of the discipline, and a more intense involvement in the process of scientific inquiry. Lab work also encourages cooperation and teamwork among students, thus reinforcing the social aspect of learning and scientific work. Together all of these elements can contribute to a positive and exciting learning environment (Gale and Andrews, 1989).
The graduate student instructor has a very important role in helping students to feel good about their lab experience. How you handle your responsibilities can make the course quite enjoyable or painful for the students. As a GSI you may have many responsibilities: discussion leader, laboratory instructor, safety monitor, grader, exam proctor, and so on. You also have an especially important role in helping to make the undergraduate students' education a quality experience. In fact, in most lab settings, the GSI has the biggest influence as to the success or failure of the lab experience for the student.
Because you work with students in small groups and on a one-to-one basis in your office hours, you have the opportunity to provide the personal touch, individual feedback, and encouragement that students need in order to succeed in a science laboratory class. You have the opportunity to get to know the students as individuals, to know their strengths and weaknesses, to understand how they think, and to challenge them to improve. In their early years, many undergraduate students need encouragement and understanding and you have the opportunity to provide them with the personal help that can motivate them to do their best work.
Another important aspect of your work will be to help students develop higher-level thinking skills and problem solving skills through active involvement, guidance and feedback. In order to do this you must not always be so quick with answers that students end up relying on you to do their thinking. Your role will be to ask the kinds of questions that will help students think through the problems and learn how to go about solving problems. In order to do this you must create the climate needed for students to feel safe enough to ask and answer questions and to participate in discussions. Often students don't participate because they are afraid they will be wrong and look stupid in front of the GSI and their peers. It is important to help students realize that everyone learns from mistakes, and that it is working through the mistakes as a group that often leads to a much deeper level of understanding and thought for everyone. Also, sometimes you will be asked questions for which you are not sure of the answers. Don't be afraid to use the phrase, "I don't know." You could use this as a teaching opportunity and tell the class how you will go about finding an answer. In any case, make a point to find the answer and explain it to the class during the next lab period.
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One other important role is working as a team with other GSIs and the faculty member in charge of the course to help make the course better. It helps everyone if GSIs collaborate with each other, sharing and discussing successes and any problems that might arise.One way of communicating with others teaching the course is through e-mail. It is also important that you provide a communication channel between the students and the supervisor and/or faculty instructor in charge of the course. Instructors are not always in a position to know what students are finding difficult or how the lectures could be more helpful to students in understanding the concepts.
Back to Beginning of Lab Guidebook
If the following information has not been made available to you, contact the instructor or supervisor to find out about:
___ The goals of the lab
___ What is expected of you
___ When and where the lab meets
___ How you obtain a class list and grade book
___ How you obtain the course syllabus
___ Drop/Add policy
___ Class size limit
___ How you obtain a free copy of the lab book and experiments
___ Where you get supplies for each experiment
___ Where you get other supplies (disks, pens, paper, grade books)
___ Where you get photocopies done and who pays for them
___ Where you get the keys for the room and outside doors
___ What help to expect (typing, copying, collating materials, etc.)
___ Getting a complete list of experiments, the instructions for each and the lab schedule.
___ Check the lab where you will be teaching
___ Locate where all of the necessary equipment is stored
___ Meet the lab technician and find out where he/she can be found, especially before, during, and after lab
___ Find out the responsibilities of the lab technician
___ Locate the first-aid kit
___ Clarify your role in the lab, for example:
___ Determine the lab ground rules
Find out who is responsible for:
___ insuring that equipment is operating correctly
___ repairing and/or replacing damaged equipment
___ ordering lab supplies
___ paying for repairs or replacements
___ Scout out the location and availability of all safety equipment in the lab.
___ If any safety equipment is missing or in disrepair, make sure there is a replacement.
___ You may wish to ask for rubber gloves, a CPR mask and a first aid kit for your lab
. ___ Attend any department-sponsored safety seminars.
___ Determine hazards contained in your lab (electrical, mechanical and other equipment, materials, radioactivity). Know how to safely handle and dispose of hazardous material.
___ Think about your response to a crisis.
___ Determine department policy for handling injuries.
___ Learn how to operate the fire extinguisher in your lab.
___ Learn departmental policy on goggles, lab coats, food and drinks.
___ Determine the University's regulations and the role that safety offices such as OSEH might play.
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*In some labs it is impossible to take this much time, but even in labs where time is scarce you will find that a 3-5 minute "stretch" break will help to keep students alert and focused (and well worth taking that extra time).
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It is essential that you put in careful thought and planning for the first lab class. This is the time to set the tone for the rest of the term. It is a time for you to get acquainted with the students and for the students to get acquainted with you and each other. For instance, you may want to know students' majors, math background, computer expertise, and similar courses taken previously, including high school. If both lecture and lab are not connected as one course, you will want to know which students are taking the lecture course concurrently. You could have students put this information on an index card.
If you plan to have the students work in groups it is important to form the groups and have some way for them to get acquainted with each other. The first day's experiment may be simple but require group members to work together so they begin to get to know each other as collaborators and resources in a learning context.
Help the students understand the relationship of the laboratory section to the overall course and point out that most of the experiments are intended to illustrate basic ideas that underlie the fundamental concepts of science. Briefly review the types of experiments the students will be performing. Emphasize that because it will generally be necessary for you to present essential information and instructions at the beginning of each session they should be sure to arrive for class on time. Show them the laboratory facilities and give them a few minutes to become familiar with their surroundings.
Much of the lab philosophy, protocol and policies should be written on a handout in addition to being discussed in class.
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Other things that should be communicated on that first day include:
It is especially important to distribute a handout that specifies policies and guidelines. This is important for several reasons: it gives you and students a written record, students joining the class after the first day don't miss this important information, and, if disputes arise later, you will have documentation. Bring copies to subsequent classes for those who don't attend on the first day. In courses with multiple sections where the instructor provides a course-wide lab handout, it is still important to have your own handout for the section(s) you will teach. Your students will appreciate knowing your personal outlook and expectations for lab, and you can give more details about your sections, e.g. expected quiz dates, due dates for assignments, embellishments on discretionary points, etc.
Experienced GSIs in your department are a good resource for finding out what specifically needs to be emphasized or explicitly explained on the first day.
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Laboratory classes are taught in many different disciplines across the University. These suggestions are meant to be generally applicable. We hope that they help make your laboratory teaching experience enjoyable and rewarding.
There is much to coordinate in a laboratory class. Not only must you know the material, you must also supervise and guide students through the lab. Preparation for labs will probably require a large part of your teaching effort. Efficient preparation is a necessity for busy GSIs, so take advantage of all available resources. Asking for advice from GSIs who are familiar with the lab can save time, effort, and even occasional embarrassment.
Read the assigned lab in the lab manual. Know what the students are supposed to learn and why. Look up any terms or concepts which are unfamiliar to you or your students. It can be most embarrassing to stare blankly into space when students ask you about some concept which was presented in the lab manual. Refamiliarize yourself with the subject you will be teaching. This involves reading the course text or reference books and bringing them to the lab for student use. Be sure that you feel comfortable and knowledgeable about the material before lab. Also, keep abreast of the corresponding lecture syllabus. If it is possible for students to take the lab without being concurrently enrolled in the lecture, find out which students are doing so.
Some labs may benefit from supplemental materials, especially those that consist solely of demonstrations (for example, botany and geology sections). If the lab manual does not have this, it may be helpful for students for you to prepare a handout to guide their observation. Comparative questions (e.g., Which is more porous, sandstone or granite?) can be useful here.
Obtain a syllabus and textbook for the lecture (or the relevant lecture course) so you know where your students are in the lecture sequence. If a lab comes before the relevant lecture, you must take this into account as students will not yet have had the theory.
Do the experiment and analysis about one week or so before your class. The benefits of preparing the experiment in advance cannot be underestimated. Running through the protocol allows you to plan for problems. As you do the experiment, pay attention to the clarity and completeness of the lab manual. You may need to warn students about possible pitfalls or supple-- ment the manual with instructions or handouts.
Think about equipment and supplies. What and how much will you need for your students? Will you need to schedule class to avoid long waiting lines for a crucial piece of equipment?
Run through the data analysis with your trial data. Keep a record to refer to during lab, and include units and necessary equations since many students have difficulty with these. Finally, know whether you can obtain the expected result. If you can't, or if you can't expect the students to do so, now is the time to plan alternate strategies.
Many large courses have weekly preparatory sessions with GSIs and the course supervisor and/or the lecturer attending. "Prep" sessions have many advantages over individual preparation. When doing the lab as a group, you can preview the experiment and the lab manual in more of an actual classroom atmosphere. As a group you can decide what to emphasize across sections and discuss how to solve difficult situations from a variety of perspectives. This is also a wonderful opportunity to learn from GSIs who are experienced with the lab.
Think about time management. When preparing the lab, keep in mind how long to allow for particular tasks. What should students be doing after a half hour, an hour, three hours? Try to anticipate any problems your students will have with budgeting their time on various sections of the experiment. Figure out how you can pace your students so they all finish on time. Sometimes you can subdivide lengthy labs, with different groups carrying out different sections. In some cases, you may need to do certain parts of the experiments or give a group demonstration.
Know your equipment and materials. Be in control of all materials needed for the lab. Check that all the relevant equipment is available and in the appropriate location (consult the equipment lists as needed). Know how to use the equipment safely and efficiently, and where to find more should you need it. Be familiar with how to turn equipment on and off, what constitutes breakage or failure, where to find a replacement or how to get around it. Fiddle with the knobs before the students do. In what units are measurements given?
Think about safety. Review the safety concerns presented by the lab and plan what you need to do to reinforce these concerns for students. Try to stay aware of any health-related problems students might have that require special consideration (allergies to chemicals, students who need rest breaks because of health, etc.).
Plan your introduction and closure. This is a good time to think about goals of the class. Think about how to integrate the lab and lecture. What concepts must be introduced or reviewed to make the material understandable? What is the take-home message for the lab and how will the students understand and retain it? Where appropriate, a short, well done demonstration can often be informative here.
These are important periods during the class, and your presentations should be short and to the point. Remember that students are there to get their hands dirty, not to listen to another lecture.
Take a few minutes at the end of lab to review the goals, and discuss results and difficulties. A group analysis and comparison of results helps students learn about the realities of the scientific process.
Plan for student preparation and write-up. There is nothing more frustrating than repeatedly answering the same questions because students didn't read the lab manual. In addition, unprepared students in a lab take longer and make more mistakes. Some options to help students prepare include the following:
Checklist for Pre-Lab preparation
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Back to Beginning of Lab Guidebook
With your preparations finished, everything is in place and ready to go for the students. Here are some suggestions for structuring the lab period.
Go into the lab early and write a brief outline on the board. This helps keep students focused, helps pace the work, and is especially important for classes that might have multiple ongoing experiments. Include pertinent announcements (review and exam dates, assignments due) to avoid spending too much time on these during class. You may wish to put this information on a handout for the students.
Begin the lab on time. Waiting for everyone to show up only encourages latecomers. Consistent promptness on your part can provoke everyone to arrive on schedule.
Briefly summarize the results of the previous week's lab. This is important for continuity throughout the semester.
Give a brief introduction to this week's lab. Here you can give any announcements, answer questions about lecture, and introduce the lab. Be concise. You might consider saving the latter part of the introduction for later, as results come in.
Demonstrate any tricky techniques or apparatus and point out the location of special materials. Gather the class close for this, and make certain everyone can see and hear. Encourage questions, but ask your own to monitor understanding. This will help you avoid explaining the same thing ten times in the first half hour. Have students form lab groups now.
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Interact with students. Take an active role with your students. Learn and use their names. Try to interact with everyone during the period. Move throughout the room. Check notebooks and make suggestions, eavesdrop on discussions or read over students' shoulders. This way you are readily available when questions come up and you can steer students in the right direction if they've gone off course.
Never pretend to know the answer to a question. Instead, if you don't know the answer be willing to look it up in a reference text, or ask another GSI or the professor.
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Let students take responsibility for learning. Try to de-emphasize the "teacher as expert" model. One purpose of a laboratory section is to teach students how to learn through experimentation, in other words, how to do science themselves. It can be hard to know where to draw the line between effective hands-off teaching and letting the class drift aimlessly. Have a procedure for encouraging students to be their own resources and follow it. For example, you might require students to pose their question to three other students before they ask you.
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Pace student progress. Many labs are too short and students will not finish unless you keep the class on track. Tell them what parts of the lab absolutely must be completed during the period. You can also periodically announce what they should be working on at a given time. Try to keep the class at roughly the same point, but recognize that students work at different rates. Aid groups that are lagging behind schedule. For those who finish early, encourage review of the material or discussion of additional questions, and expect some socializing.
Provide a sense of closure and clean up. With students working at various paces, some people will finish before others, and it can be difficult to gather everyone's thoughts at the end of a chaotic period. However, a good conclusion reinforces learning. It is a time for reflection and processing observations. Post results on the board and let the students draw their own conclusions as a class. If time is short, you can begin this when most people have finished. Allow sufficient time for cleaning up. Before leaving, check that all equipment and utilities such as gas, air and water outlets have been turned off.
There may be a large variety of equipment in use during the semester, some of which will probably be new to you. However, all of it will be new to the students, and you will be teaching them how to use it. A general knowledge of each piece is very useful, i.e., its purpose, how to turn it on, in what units measurements are given, and whether a manual exists. Find out how to do any calibrations for the lab. Be familiar with functions of all controls. Place tape over any controls which students should not change, or encourage them to do so for the sake of the experiment and check that they are properly reset at the end of lab. Remember to allow sufficient warm-up periods for equipment that needs it.
One of your most frustrating responsibilities may be to maintain enough functioning equipment for your classroom. Many teaching laboratories are equipped with outmoded machines that have been abused for years. Should you teach in a large course, the vast numbers of students sharing equipment virtually guarantees that equipment may be miscalibrated or non-functioning by the time your class uses it. If students cannot work on the lab for a few minutes while equipment is being replaced or repaired, you might use the time to work on calculations or discuss available results.
Do not leave defective equipment in the room. Make sure it is turned in for repair.
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As an instructor, you have the responsibility to ensure a safe learning environment for you and your students. Laboratories present many more potential hazards than the conventional classroom, and it makes sense from everyone's standpoint to have prepared for situations you will hopefully never have to handle. The classroom situation is often unpredictable and you may wish to provide basic written safety precautions to your students.
Within the University of Michigan, the Department of Occupational Safety and Environmental Health, Laboratory Safety Section (647-1143) offers safety resources for University employees, including graduate student instructors. Laboratory safety manuals are available which detail University policy on laboratory rules and maintenance, hazardous waste management, electrical safety, chemical spill procedures, and emergency and first-aid procedures. OSEH also provides training in laboratory safety and right-to-know issues.
Here are some basic guidelines. Protective clothing (lab coats, safety goggles, gloves, shielding) should be available for everyone handling dangerous materials or equipment. Separate waste receptacles for glass, biohazards, and radioactive materials should be in place. For additional safety concerns pertinent to your course, consult the course supervisor.
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Those using equipment can monitor it most frequently, which often puts GSIs in the best position to check for safety hazards. Electrical cords should be in good condition; equipment with worn or broken cords should not be in use. All electrical equipment should be grounded with either a three-pronged plug or double insulation. Never use electrical equipment near flammable solvents, and do not handle any electrical connection with wet hands or when near or standing in water. Any electrical equipment used near water must be plugged into a socket with a ground-fault interrupt trip circuit. Check that your students do not bypass this precaution.
To extinguish electrical fires use only a multipurpose ABC, BC, or carbon dioxide extinguisher. Never try to put out a fire with water or a water-based extinguisher.
Because chemical vapors can be toxic or cause irritation, when using odor to identify chemicals do not place your nose directly over the container. Instead, gently waft vapors toward your nose using your hand. Never pipette by mouth. Materials that produce toxic fumes, such as waste cyanides and sulfides, should be stored in a fume hood. Know how to correctly dispose of waste chemicals. Never dispose of chemical waste by pouring it down the drain. This violates federal, state, and local government regulations. In case of a chemical spill, notify the class and ventilate the room. Supplies for cleaning chemical spills should be available to you.
In a chemical emergency, remove all contaminated clothing and wash the affected area at the nearest shower or eyewash station. Report chemical spills and emergencies to your supervisor.
First aid should be used only to provide assistance until professional medical attention can be given. Procedures for basic first aid are found on page 4 of the OSEH Laboratory Safety Manual. If an accident or injury occurs during your class, report it to the laboratory supervisor and, if necessary, notify medical authorities. You or the supervisor should accompany the student to the University Health Service for treatment, if needed.
Emergencies
In an emergency, dial 911. |
Other emergency numbers:
Poison Information Center:
800-222-1222
Occupational Safety and Environmental Health (OSEH): 647-1143
Other (________________________________________):
Back to Beginning of Lab Guidebook
Too often we feel that the only things we should or are allowed to teach in a science lab are the specific sets of facts or techniques that are outlined in the lab manual. However, if this gives the students an impression of science as a restricted and procedure-bound set of steps, they would never develop any of the higher-order skills that are required to be a professional in any field. There are a number of additional concepts that a GSI should keep in mind as being of importance to expose students to and take every opportunity to introduce them in discussions and presentations in and out of the laboratory.
As mentioned above, the ultimate aim of training students in a science lab is not merely to fill them with facts but to help them learn how to approach and analyze a problem. How do we formulate questions and establish facts? How do we determine the meanings of observations? How do we reason? Teaching students to think critically can be approached by helping them develop an awareness of the steps one goes through in a scientific investigation.
1. How to ask questions. Scientists spend their time trying to answer questions for which there are no known answers. But the quality of the research and importance of the answer often depends on how good the question is. Asking insightful and meaningful questions is a skill that must be learned and part of the students' training in the laboratory should include practice in asking questions. Encourage the students to ask questions for the sake of forming the questions and analyzing how it is done.
One exercise that you can use in lab or as an outside exercise to encourage students to develop their skills at inquiry is the 20 Question Game. Have the students sit quietly in the lab or elsewhere and think about the course work or their surroundings. Each student should write down 20 questions that come to his or her mind about the body of knowledge encompassed by the course. It is not important whether the question has a known answer. The goal is to give the students practice in using their imaginations.
Afterwards, discuss their questions with them individually or in groups. What types of questions did they ask? Usually their questions will fall into a few categories: why is it so, how does it work, structure and function, what if.... and where it fits in a general hierarchy. What are the advantages and difficulties of each kind? How would one go about answering them? Would the answer to the question say anything significant about the nature of patterns in the discipline? Can the question be feasibly answered given available time and resources? Are the questions generalizable? With practice, the students (for example in the life sciences) will go from asking questions like, '"Why is this tree taller than that one?" and "How many molecules are in the human body?" to "What are the factors that control plant growth?" and "How do cells select which molecules cross membrane boundaries?" In a short while, the students will find that questions come more freely to mind and that many of them could lead to productive research programs.
2. How to answer questions. Finding the answers to questions represents the physical labor of doing science. As you talk to students and answer their questions, tell them about the process by which the answers were found.
The basis of most scientific investigation is an observation about a pattern. A tentative explanation for the pattern can be given and is called a hypothesis. Before the explanation can be accepted, however, it must be tested. A prediction is made about what should be seen under other circumstances or at a different time if the explanation is correct. The results of the experiment may be as predicted, and therefore support the explanation and add to our confidence in it, or may not be as predicted and indicate that the explanation needs to be revised. Ideally, this process is repeated until the results from all the experimental tests can be explained by only one hypothesis. Point out to the students that by this process you can never prove a hypothesis; you can only fail to disprove it. Science advances because as techniques are improved additional predictions can be tested to further refine the hypothesis.
This process of investigation serves as a heuristic model to describe the thought processes that go on when a person tries to answer a question. Another set of skills necessary to answer questions are those involved in running a valid experiment. The details will vary from discipline to discipline, but virtually every experiment involves first defining the terms with which you are describing the system, identifying the variables and assumptions, identifying the possible sources of error, and determining what is already known about the system. A possible step involves comparing an experimental group to a control group, which should differ from the experimental group in only one variable. Experiments can be either manipulative, in which the scientist causes the difference between the two groups, or natural, in which advantage is taken of natural differences between groups. The strength of the experiment is influenced by both sample size and replication of experimental and control groups.
3. How to deal with numerical data. Students often want to record their results on paper towels or scrap paper. These are easily lost and are hard to keep organized. The data should be recorded in a lab notebook or on data paper that can be easily stored safely in a binder and with column headings and descriptions that will allow the data to be interpreted at a later time. Encourage the students to treat all their data as important, even if they think they already know what the answer will be, and to make their measurements with all the accuracy allowed by their equipment. They should also think in advance about how they will analyze their data. This will help them to avoid collecting data that cannot be analyzed or that do not answer their question.
When the students analyze their data, have them keep in mind the question that they are trying to answer. Students often analyze their data in a particular way only because they saw that the data could be put together in that fashion and not because it addressed their question.
In some of the introductory labs many students will not yet have studied statistics and therefore you can only expect a minimal amount of sophistication in how they analyze their data. The best that many students will be able to do to simplify their data is to calculate mean values. However, take the opportunity to tell them about the need for statistics to estimate the uncertainties in their results. Even though a hypothesis can never be proved, a statistical test can tell you how likely it is that your results could have occurred by chance or error.
In more advanced labs most students will come in with knowledge of calculus and statistics but you may have to help them learn to apply it to the material of the lab. Again, know the math background of your students.
The hardest thing for many students to learn is how to interpret their data. Introduce them to the ideas of causation and correlation. For example in the life sciences we are usually interested in discovering what the cause of a pattern is but can often only determine if two variables are correlated with one another. Also, remind them of the complexity of the experiments. Not only is any pattern likely to be influenced by more than one variable but each variable is likely to have multiple effects.
Encourage them to display their data in ways that are easily interpreted by other people, such as in graphs or tables. This will help them learn to communicate their results and will often give them new ideas about what their data might mean.
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Both written and oral communication are important in every profession. However, many students feel that because they are not in an English class that the quality of their writing is not important. Strongly discourage this view. Clear and effective communication skills are vital no matter what profession the students plan to enter. Make every effort you can to comment constructively on both their basic writing skills and their ability to effectively communicate their scientific ideas on paper.
Also encourage them to practice their oral communication. Students often have difficulty expressing themselves verbally in science classes because of the large number of new terms (this is especially true of introductory labs). At first, get them to think about what they are trying to say in non-technical language. Then provide for them the scientific terminology for their ideas. In this way they will improve their ability to interact verbally with someone and to use scientific terminology to increase the precision of their communication.
Scientific communication also involves the use of visual aids. Get the students to draw diagrams of concepts and specimens that they observe in the lab. If they are required to give formal oral presentations in the laboratory, help them to organize and use illustrative slides and overhead projections.
As we have discussed before, sciences are more than collections of facts and observations. They have a historical and philosophical component as well. Talk to the students about the history of the current understanding of a field. Encourage them to think about the social and ethical implications of scientific knowledge. The world today is rapidly changing because of many advances in the various sciences and the impact of this change on our society is something about which everyone should be aware. For example, research in biomedical and genetic engineering, agriculture and fisheries practices, and medical technology all have emotional as well as technical content. Encourage your students to think and talk about the implications for society of the subject they are studying. This will often stimulate them to learn more about the subject because it allows them to generate their own reasons for why the material is relevant.
In addition to the historical and ethical importance of a new fact or observation, encourage the students to think about how scientific information might influence future research. Remember that one of our goals in the laboratory is to teach the students how to ask questions.
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A difficult thing to convey to students is that everyone is capable of doing science. Their lack of confidence in their scientific abilities often results from high school science courses in which they were taught only to memorize facts and formulae. As a result, they never learned that science is as much a way of thinking as it is a body of knowledge. These students can often be helped by using examples of hypothesis formulation and testing that relate to non-laboratory situations. For example, people often go through the process of formulating, testing, and revising a hypothesis whenever they burn a cake in the oven or their car refuses to start. Get them to recognize that they already know how to do science and that by taking a science course they are simply broadening their awareness of the world around them.
Another attitude that students occasionally have is that science is an impersonal and unemotional subject. Especially in introductory courses, laboratories are often prearranged exercises in which the GSI already knows the expected results. Therefore, the whole process appears cut-and-dried. In your discussions with them, let them know that science is a way of exploring the unknown and that all of our explanations for patterns in nature are tentative. The force that drives most scientists is the excitement of exploration and the chance that something completely unexpected may be discovered. Many of the most significant discoveries, such as the discovery of penicillin, have come about by accident; observations were made in areas and under conditions that were not planned. Science offers everyone the opportunity to let their mind go where no one else's has gone before.
Your students will inevitably ask how to study for a test or complain that science is nothing but the memorization of facts. Tell them that they should try not to memorize but to understand the material; in other words, they should be able to explain in some depth the reason why a pattern is the way it is. If in the face of their logical analysis the pattern still doesn't make sense, then perhaps they have identified a new direction for research. Simple memorization of facts, however, has never resulted in any lasting contribution to our scientific knowledge.
Remind the students as they work in the lab of the need to remember and use information that they have acquired from other sources. This includes material as basic as simple arithmetic. In lower division courses students will occasionally say that they cannot multiply because they have not had math in awhile. Do not let them believe that this is a valid excuse. Encourage them to review these skills immediately and require that they use them.
In upper division courses, encourage students to use information acquired in other courses. For example, if you are teaching a physiology laboratory, you may not have time to teach the students about biochemistry. However, many physiological processes are determined by rates of chemical reactions. If some of your students have had biochemistry, get them to share their knowledge with the others in the class. This kind of interaction impresses upon them the value of taking a diversity of science courses, of the importance of remembering the material in a course even after it is over, and of the interrelated patterns and connections between various science disciplines.
Often students work in groups in the interest of time and equipment. Ultimately, however, every student is responsible for his or her own performance. Encourage them to be sure that they can solve the questions and can perform the techniques for themselves.
By teaching your students the skills and perspectives described above, your students will have gained knowledge and abilities that will stay with them long after the particular facts of your discipline have become outdated.
This section was adapted with permission from Reference Manual for Teaching Assistants in Life Science Laboratories, Center for Instructional Development and Research, The University of Washington, Seattle, 1988.
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This unit is in two sections. The first section on "Group Work in an Introductory Science Laboratory" was written by a GSI, and is based on his experience in using groups in a lab setting in Geological Sciences. The last section gives general information about using groups.
Introductory science laboratories in the university setting often have to rely on the utilization of groups to efficiently use resources that are available. Many graduate student instructors try to avoid this type of interaction among the students by trying to get more lab materials, or by including the entire class in lectures. During my teaching of Geology/Geography 201 I found that group work by the students, with small group-instructor interaction, was an effective way to present material in the introductory laboratory.
Science classrooms are often equipped with tables around which the students sit, rather than the traditional rows of individual desks. My classroom had four square tables with seating for one person on each of the sides. This led to the students forming their working groups the first day. The students tended to disperse themselves evenly around the available tables as they came in. For instance, the first four people that came in tended to pick four different tables. As more students came in they also distributed themselves randomly and evenly among the tables. To some extent, this distribution resulted in grouping of different personalities together because the students did not know each other when they entered the class. I thought that the students might regroup as the semester went on, but instead they much preferred to use the same space for the entire semester regardless of how they interacted with their group. The random distribution of individuals among the groups was very much what I had hoped for.
Teaching assistants often have a short (sometimes long) lecture containing information for the students before they start the lab. I found that the longer my lecture was, the more students were apt to tune out what I was saying. I think it is important to start out the class with everyone on the same wavelength. I started my labs with announcements pertaining to the class, then solicited questions pertaining to labs I had handed back and labs they had just handed in. This allowed me to answer questions the students may have had in front of the entire class. It also allowed the students to see that others in the class may have had the same questions they did. At that point I briefly explained the new lab and handed it out. The students then worked on the labs in their small groups.
In labs of 15 to 20 people, group size is best limited to four or five persons. I found that three people tended to work independently, and more than five allowed for someone in the group to avoid participating. Groups of four or five were large enough that students were more apt to articulate an idea, thinking that someone else would have similar thoughts. The groups were also small enough that students who tended to shy away from asking questions in a large group would pose those questions to peers in the smaller group setting. Group size will depend upon the total size of the class, the amount of available lab materials, and, interestingly, the size of the tables. Don't squish eight people around a table meant for four, even if you don't have enough lab supplies. Wait until one group is done and rotate the materials, or the students, about the room. In the same vein, don't spread four people around a table meant for ten. This is no longer a group, but rather four individuals.
The formation and use of groups in the class has more advantages than just the effective use of resources. The division of my class allowed the students to work at a pace at which they were comfortable. I was given lab exercises that were used in previous years, but had the freedom to make any changes I felt appropriate. I made sure that the labs were written so that the first exercise covered basic ideas that all students should have been familiar with. I allowed groups to forge ahead if they understood the material, and I didn't have to hold them back if the rest of the class was having more trouble.
I worked more closely with, and gave more help to, one group if they were struggling with the material and the rest of the class was not. The "ifs" in the sentences above are very important. It is essential when working with groups that the GSI recognize the dynamics of each group. For example, one group consistently seemed to comprehend the material and move quickly through the lab. With this group it was important to check that everyone was working at the same fast pace. If four students were comprehending the material and one was not, s/he tended to copy down answers, so as not to slow down the rest of the group. To check understanding as I worked with the groups, I asked each person if they understood the material. I posed some challenging questions for each member of groups that were working particularly quickly. This allowed me to slow the group, make them think about the consequences of the work they were doing, and find out if individuals were having problems with the material. I looked for group dynamics from across the room as well, checking that all members were engaged in the discussion at some point. If they were not, I intervened to tie the group back together with some questions.
A student that was having trouble with the material could also slow the group down to where they were becoming unproductive. Often if one student fell behind, the others in the group tended to "goof off" while waiting for the slower student to catch up. I tried to stimulate these groups by asking questions from the lab to the students who had finished a particular section. I also posed questions to draw the students back into a group as a whole. For example, I would ask students who had finished a section how they did a certain part. Then I asked them if they could explain how they thought through the problem, and how that might help a hypothetical slower student in the group. Not only did this help any slower students with ideas and additional points of view, but it also made the others think again about their own work. After I did this exercise once or twice, I found that the students took on a sort of responsibility for the others in their groups. I found that, by using groups of four to five, the students want to be at the same level as others in their group. Students that understood the material, or to whom I had explained the material so that they understood, wanted to show their peers that they had gained knowledge. It was a status symbol to show the others they had this knowledge. The students who didn't understand the material looked at their peers and said "If s/he can do this, I must be able to do it." These two attitudes had an amazing effect on group dynamics. Suddenly I had groups of teachers and students in my class. The students with a good grasp of the ideas wanted to pass on their knowledge, and the students who were confused wanted to understand the material. Not only did this make it easier for me to teach, the students became more comfortable working with one another as well.
Although it certainly was a great feeling to have the groups working on their own, I never lost contact with any group for more than 10 minutes. If I had been fielding questions from three of my four groups, I either quickly checked on the fourth group, or sometimes just shouted to them that I saw them working well (or not well) so they knew I was still interested in their progress. If the lab had kept the students busy for the entire period, I tied the entire class back together at the end by asking again for general questions and previewing what we would be doing in the next session.
Lab groups are an integral part of lab science. The necessity of working in groups is often brought on by limited supplies, but groups can also be an effective teaching structure. The small-group format allowed me to get closer to the students and gave them opportunities to ask and answer questions of each other. I don't feel that instructors should shy away from using this structure, but instead should try to tailor their classes for effective use of small groups.
Working in lab groups is an opportunity for students to learn to work with other students and learn to talk and share ideas about the material. This group experience helps prepare them for teamwork later in their careers.
The most effective lab groups consist of two to four students. The number of students per group can be determined by such factors as the nature of the experiment and the availability of equipment. When selecting lab groups, the instructor has several options:
Each method of selection has its advantages and disadvantages. With self-selection, students can choose people they know and would like to work with. However, this method can make students who don't know others in the class feel awkward during the selection process. It can also provide for unfair groupings (i.e., motivated "high performers" may group together). Finally, self-selection does not guarantee that the chosen groups will make a good work group.
Random selection, either through location or instructor choice, does provide a more balanced mix of students in the groups. It also provides exposure to real life settings, where individuals are often assigned their teams or task groups. On the other hand, random selection cannot guarantee a successful group, and some groups may not work well together.
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Effective groups use a balance of task-oriented and group-maintenance oriented behavior. These groups get their job done on time and maintain a positive, inclusive climate during their work. When groups don't work well, the instructor can help them figure out why and what they can do about it.
During a lab, the instructor monitors group progress and makes sure that groups are moving along with the experiment. Occasionally, groups will move through an experiment more quickly than anticipated. While it may be that these groups are highly efficient, the instructor should check that they have completed all steps, have set up the equipment correctly, and are recording all data.
More often than not, however, groups will move through an experiment more slowly than anticipated. In this case, the instructor can help them to be more efficient by finding out what is delaying the group. Some common causes for slow groups are lack of understanding of what to do, lack of preparation, lack of motivation, or group conflict.
If students do not understand the lab, the instructor can use guiding questions to help them discover what they are doing and why. If students do not understand a specific procedure, outlining steps and clarifying terminology will help. When monitoring group progress, some instructors will handle the "quick question" groups first, and then turn to the groups they know will need more input.
If a lack of preparation or motivation is the reason for a slow group, offering encouragement and showing the benefits of timely completion for the students is often a good incentive. For groups with little motivation, breaking the task into manageable segments and helping the groups to set specific tasks and goals will help them to gain direction.
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To help groups deal with conflict, the instructor should work as a facilitator rather than problem solver. Drawing out passive students will help these students feel more involved and will encourage more equal participation. Another facilitation technique is to help the students focus on issues rather than personalities. Having students search jointly for solutions is also a good way to have them solve their own conflicts. For groups with different work styles, help them to divide the task and outline roles and responsibilities for each member. This can encourage equal participation and minimize conflict.
In some labs students are encouraged to write their lab reports together and everyone in the group receives the same grade. If this is the case in your lab, students will sometimes need guidelines on how to collaborate in their writing. In other labs, even though students work together in lab, each student must write his or her own report.
In this case, it is important to avoid plagiarism and related issues. Students are not always sure what it means to plagiarize, so there needs to be a clear, written policy and guidelines for students to follow. For example, one of the rules might be that any analysis done in a group should be acknowledged.
It is important for you to check what is acceptable in your lab and clearly communicate guidelines to students. A sample lab write-up that illustrates your guidelines may be helpful for students.
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Writing up a lab serves several purposes. First, producing a report allows students the opportunity to collect their observations and interpretations into a cohesive and coherent format. Secondly, it helps students prepare for their future careers, illustrating the process of conducting research and documenting results.
The following suggestions should help make the grading of lab reports easier.
Lay out grading criteria clearly and in advance. A written statement clarifying what an "A" lab is, what a "B" lab is, and so on can outline teacher expectations for the students. It can also serve as a useful reference tool should a student have a question about a grade received. Likewise, policies on late lab reports should be written down and handed out at the beginning of the term. Again, this reduces possible misunderstandings and allows for easier decision-making during the term.
Determine your policy for lateness. Some policies for lateness have included: no late reports accepted, late reports accepted only with valid excuse, late reports accepted with grade reduction penalty, and one late lab accepted without penalty during the term. Check with the professor of the course to see if there is a standard late policy for the sections. If there isn't, choose one that fits with your philosophy and apply it consistently throughout the term. When determining your late policy, you should also pay attention to when labs are due. If you are setting due dates that are difficult for students to meet, then you will probably have more late lab situations to address.
When grading lab reports, read through several before making any comments or determining scores. This allows you to form a baseline impression for the class before grading individual reports. It also helps to form a checklist of criteria that you can refer to when grading, to ensure consistency in your marks and to give students a specific understanding of what you are looking for in that report. Find out if there is a course-wide checklist for grading each lab to promote consistency across labs.
When developing your criteria, decide how heavily you will weigh content vs. form. Content refers to the substance of the report: data, results, interpretations, conclusions. Form refers to how the substance is presented: organization of material, graphs and tables, clarity of writing, and grammatical correctness of sentences. Many courses have a standard format which students should follow in doing their write-ups. Again, check with the course professor to develop a clear understanding of grading criteria for reports. It also helps to check with other GSIs teaching the same course, or with those who have taught it previously.
As with "real" science, not all labs will work out successfully for students. In many labs, the report will not be graded on the success of the results, but on the students' interpretation of their results. Thus, students who do not get the desired results from an experiment, but make a thoughtful analysis of why or of what should have occurred would not be penalized in their write-ups. Evidence of good interpretation or analysis involves identification of patterns or contradictions and a specific, plausible and well-supported explanation for these results.
Give useful and prompt feedback to students. In addition to determining a grade for the report, your role as a GSI involves giving useful feedback to students. You should make comments on lab reports and return them with sufficient time for students to learn from the comments before turning in their next report. When providing feedback, remember to focus on functional comments, not subjective opinions. For example comments such as "Could there be another explanation?" are more productive than statements such as "Oh really? Also, when providing feedback, try not to overwhelm the student. Sometimes, too many comments on a page can be daunting to a student who wants to improve. Instead, pinpoint a few key issues for each report. Spending extra time to thoroughly grade the first assignment and provide prompt feedback will greatly ease the grading procedure for the latter part of the semester.
Finally, remember that learning to grade is an ongoing process. As you gain experience as a GSI you will develop new methods and systems for grading, and will constantly fine-tune your processes. Sharing grading issues and ideas with peers can help you in this process. If in doubt on a grading issue, consult the appropriate senior personnel. It is difficult to alter grades once they are assigned.
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Giving students clear guidelines for what is expected in a lab report or how lab reports are evaluated will make your job of grading much easier. On the next few pages are examples of guidelines for lab reports that have been used by GSIs.
*This will vary for specific labs. See lab-specific format.
Some general comments that apply to many reports are given below, with some specific comments written in. You may also find comments on your paper. Total points possible are 35.
FORMAT
Title: The title of an experimental report should indicate the factors being manipulated, the effects or responses being measured and (sometimes) the specific topic or organism under study. Be as concise as possible.
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Introduction: The introduction should provide a clear statement of the problem or questions addressed by your study. It should give references to relevant reports by other workers and should include enough background information to make your report understandable as an independent unit.
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Materials and Methods: This section should (1) enable others to judge whether your techniques justify your conclusions and (2) provide enough information to allow your work to be repeated. Since your protocol was detailed in the lab manual, a short outline or explanation and a formal reference to the lab manual will suffice. Include any deviations from the lab manual protocol.
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Results: Tables and figures, although important, are not enough for this section. Describe your results briefly, but indicate trends in your data that will be discussed in the next section. Tables and figures should be numbered, labeled, and mentioned in the text. The dependent variables should be on the vertical axes and independent variables on the horizontal axes. Linear, semi-log or log-log graphs should be used where appropriate.
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Discussion: The discussion should include an error analysis (or at least an estimate of uncertainties), any inductions drawn from your results, and whether your data are consistent with relevant models or hypotheses.
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Summary: The summary should be a shorter version (1-2 paragraphs) of the paper for those who don't want to read it in detail. This section should be independent of the paper. Tell what you did, what happened as a result, and what you concluded.
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Literature Cited: Any facts or ideas that you did not generate yourself must be attributed to the source where you found them (including other people). Indicate such references by inserting the author's (authors') name(s) and the date of publication at the appropriate place in the text and by listing a complete citation under Literature Cited. If any of the analysis was done as a group effort, this should be indicated. All references cited MUST be mentioned in the text. See the lab manual supplement for complete citation format.
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SCIENTIFIC CONTENT:
Is the reasoning accurate? Are all possible inferences made? No illogical inferences drawn?
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STYLE, GRAMMAR AND SPELLING
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TOTAL ___/30
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*This will vary for specific labs. See lab-specific format.
** = the most crucial sections of the report
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Chadwick, N. "Introduction to Lab Sections," Learning to Teach, A Handbook for Teaching Assistants at U. C. Berkeley, University of California, Berkeley, 1989, pp. 28-30.
Gale, R. A. and Andrews, J. D. W. "Teaching in the Laboratory," A Handbook for Teaching Assistants, Center for Teaching Development, University of California, San Diego, 1989, pp. 84-88.
Laboratory Safety: Practices for Progress. 1990. Occupational Safety and Environmental Health, The University of Michigan.
The University of Michigan Hazardous Waste Manual.
The University of Michigan Services for Students with Disabilities Faculty Handbook.
Trombulak, S. C. Reference Manual for Teaching Assistants in Life Science Laboratories, Center for Instructional Development and Research, University of Washington, 1988.