Laboratory TAs

As a laboratory teaching assistant, you are responsible for developing the scientific proficiency of your students. This covers a range of skills, from ensuring that students have a grasp of the work to be done, to introducing them to basic laboratory and safety skills, to supporting students through their experiments, to the helping them deliver the final product: a laboratory report.

Crucial Questions

We suggest addressing the crucial questions listed below before the laboratory session.

Five crucial questions about lab teaching:

  1. What are the most important things a student should learn from this experiment, perhaps things that cannot be learned by reading a textbook or listening to a lecture?
  2. How can I get students engaged with the experiment, as opposed to mechanically following the instructions?
  3. Where are students likely to get stuck, or to do the wrong thing without realizing it?
  4. What can I do or say to make this experiment more meaningful—how does it relate to the course overall, to other experiments, to current technology, to our understanding or appreciation of nature, or to how we live our lives?
  5. What will students and their apparatus look and sound like when they are doing their experiments well, and how will I recognize 'teachable moments' from the visual, auditory, and behavioral cues?

Five crucial questions about lab logistics:

  1. What milestones can be identified in the experiment—things that students should have achieved at certain times through the lab session—and how will I check that they're making good progress?
  2. If an apparatus is missing, broken, or malfunctioning, or if it breaks while in use (perhaps spreading glass shards or hazardous materials), what do I do?
  3. If I need assistance to cope with lots of students needing help at once, who do I call?
  4. If we need to evacuate, how do I direct the students, where do we go, and where do we assemble? What needs to be turned off or otherwise secured before we leave?
  5. If someone is injured, where do I find things like eye showers, a first aid kit, a spills kit, a paramedic?
Preparing for Class

It is important to be in constant communication with both the course instructor and the laboratory coordinator. Too many problems have arisen when assumptions are made about the lab TA's level of understanding about their role. The best way to head these off is by having conversations with the relevant people.

Familiarity with the work that your students are covering in their lectures is vital. Therefore, it would help you in your lab TA work if you attended all lectures (or as many as possible). That way, you are effectively refreshing your knowledge of the content prior to the laboratory session.

Familiarity with the laboratory equipment, processes, and safety procedures is equally important. Students quickly lose confidence in, and respect for, a lab TA who does not appear to know how the equipment works, or who leaves out a step in the experimental process, and then has to try and make a ‘save’. If possible, go to the laboratory a day before you see your class and practice the experiment. That way, you can make any major mistakes before you see your class.

Running a Lab

Make sure that you are early for each lab session so that you can prepare the benches and write the necessary information and instructions on the board neatly. For the first few lab sessions, include your office hours on the board and encourage students to make use of them.

Begin each lab by stating what the objective of the day’s experiment is. In other words, what knowledge and skills should the students leave the laboratory with? It is also worthwhile to briefly remind the students how the work that they are about to do connects with the work covered in lectures.

Then, provide them with a clear, step-by-step explanation of the experimental process (which includes a description of how to use the equipment as well as any safety precautions they need to be aware of). Try not to leave anything out on the (potentially mistaken) assumption that it should be obvious to the students. Keep checking in with the students after every step in this process to make sure that they understand.

Be careful not to talk for too long—you will need to find a balance between giving the students sufficient information to complete the experiment, and boring them with too much information.

Throughout the explanation, encourage students to engage with you and ask questions. It is important that they recognize the lab as a safe space for learning. Also, try not to answer their questions straight away—ask the class if anyone wants to attempt an answer. That way, you will encourage a more participatory learning experience for them. Also, validate their answers even if they are incorrect—a wrong answer is a fantastic opportunity for learning because you can explore why the answer is wrong.

Always have a 'plan b'—what you would do if there was an equipment malfunction, for instance.

Throughout your explanation, keep an eye on the students' body language—frowns, deep sighs, and nervous movements generally denote confusion and uncertainty. When you recognize this kind of behavior, stop and encourage the students to tell you where they started getting lost. Then, go back and start your explanation again. Alternatively, you could ask one of the other students in the group to explain the work.

Try and 'chunk' the work as much as possible. That is, break it down into smaller, more manageable steps—this makes the stages easier to follow.

Once the students have begun to do the experiment, move between the groups frequently, without hovering. When you see students having problems, go over and ask them some constructive, probing questions about where they think that they might have gone wrong. Avoid the temptation of jumping in and giving them the answer or solution immediately. Rather, let them try and reason it out for themselves. This is a powerful learning opportunity for them.

In the last few minutes of the lab session, ask one or two students to summarize the experiment, its procedure, and the results for the rest of the class. Alternatively, you could go around the class and ask each student to name one thing that they learned in the day's lab that they did not know before. Ideally, there should be no 'repeats', but it is not the end of the world if more than one student lists the same thing. What is important is that they have a chance to reflect on and articulate the day's work.

After the lab, do a reflection of your own: think about what worked well, and why. Also, what did not work that well? How might you have handled the situation differently? It would be useful for you to capture these thoughts in a journal so that you can revisit them from time to time.