THE TA IN THE LABORATORY
The lab section is offered in conjunction with the large lecture course so that the students have the opportunity to acquire technical skills. This hands-on experience encourages them to develop a spirit of inquiry and allows them to live for a year (at least during the lab period!) as practicing chemists.
To realize your full potential as a laboratory instructor, you will have to recover some of the enthusiasm YOU had when you were a freshman in a chemistry laboratory.
- Read the entire experiment before you go to the staff meeting. It is only after you have read the experiment that the instructions given at the staff meeting make sense.
- Get acquainted with the Teaching Laboratory Services and laboratory technicians, they can be of invaluable help. Stop and see them at the beginning of every lab to check for last minute developments and pick up your bucket.
- Get to the pre-lab on time. Listen to what is being said so that you and your students hear the same instructions. Some experiments have been modified to suit this laboratory and its limitations.
Safety takes on special importance when you are directly responsible for the health and well being of 16 laboratory students. Window shattering explosions are rare, but it is not uncommon for students to get cut from glass tubing, get acid burns or ignite their lab notes with a Bunsen burner. You must therefore refer constantly to the ACS Safety in the Academic Chemistry Laboratory manual and to the different sheets in this manual that refer to safety and conduct (both your students’ and yours) in the laboratory.
You are responsible for enforcing the safety contract and making sure your students abide by it. If faculty or the safety committee notice that these rules are not enforced in your laboratory, the student at fault will be expelled from the lab and get a zero for the experiment he/she was working on. A memo will also be put in your file about your carelessness on rule enforcement. A number of these memos in your file could seriously jeopardize continuation of TA support for you. (See below for all of the criteria your performance will be evaluated on.)
SUPERVISING THE EXPERIMENT
- Get to know the students quickly and make full use of the lab period to teach and observe. DO NOT spend the lab time grading quizzes, lab reports or chatting with other TA’s. Try to talk with each student at least once during the experiment. Technical and procedural matters can be handled quickly with a few words of advice or a very brief demonstration, but your primary role is to help the students master the steps of scientific inquiry.
- Helping students master each step is not an easy task. There are a variety of ways to help students get to each step and solve problems for themselves. Instead of answering questions, you can ask them. You might also try to correlate principles covered in the lecture during the week with the experiment at hand.
- However you approach this part of your task, refrain from giving outright answers or advice. If the student asks, “Why don’t I get a precipitate?” try asking him/her a series of questions which will lead him/her to discover the reason rather than you explaining why the experiment failed. Of course, sometimes the reason will be relatively simple (You used potassium nitrate instead of potassium nitrite.), but just as often the reason can be more substantial. Students may become frustrated if they can’t get a straight answer out of you but in the end they will learn more and, if they are honest, thank you for it.