Thinking Skills in the Laboratory
Instructional Strategies — using Thinking Activities —
for helping students learn scientific thinking skills in science labs
This page has been revised
and moved to a new location:
ThinkingSkills in the Laboratory
The main body of the original page has been deleted. But below you'll find "extra ideas" to supplement asection about Potential Problems in therevisedpage about Thinking Skills in the Laboratory:
Quality of Teachers
Consider four types of TAs in DB labs: 1a) Those who, like myself, are shy but can talk about ideas, will usually do much better, in many ways, with DB. 1b) TAs who are socially fluent will have a great time, and so will their students. There may be concerns about using DB with: 2a) shy TAs who are not comfortable with talking, even about ideas and chemistry, and 2b) foreign TAs who are not skilled in speaking English. But in most cases these worries are exaggerated beyond what is justified. First, during the semester both types of non-fluent TAs (shy and foreign) will improve their social and linguistic skills as a natural result of the interactions that occurin DB labs. Although in conventional labs these TAs usually solvethe "balance problem" by choosing the easy way, by ignoring studentsand avoiding conversations, the structure of DB naturally leads to interactionswith students and between students, and thus to opportunities for learning bystudents who will become better thinkers, and by TAs who will becomebetter teachers. DB leads to increased experience in listening andspeaking. This practice will help shy TAs and foreign TAs improve theirlanguage skills, which will improve their graduate school experience and theiroverall professional (and personal) development.
To achieve consistently high quality of teachingin labs, effective TA preparation is a high priority. This will help allTAs, especially those in the latter two groups who begin with a lower level ofverbal comfort and/or fluency. And all TAs, including fluent talkers, willbenefit from mastering strategies for getting students to talk more freely duringdiscussions. { In fact, these "student stimulating" skills maybe especially useful for verbally fluent TAs, who must convince themselves thatthey don't have to dominatethe discussion. An equalizing factor: if a TA who is less fluent can producea good atmosphere for learning, students who are properly motivated may be willingto contribute more during discussion, out of necessity. } Just "knowingtheir stuff" (due to being prepared) will help all TAs feel better and teachbetter. / The prelab preparation can be done by the Lab Coordinator,or by TAs who have this responsibilityas part of their assigned duties.
Evaluation and Grading
If lab grades are assigned (as in Options 1, 2 or 3 above), what grading methods can be used?
* During lab, a TA can evaluate the quality of work (lab techniques, ability to follow directions or to improvise,...) and discussions (quality and quantity of contributions,...).
* Written reports for work done inside or outside the lab.
* Labs can include built-in accountability for work that is qualitative (identifying an unknown chemical,...) or quantitative (determining a concentration,...).
* Skill exams (to test qualitative or quantitative analysis, lab techniques such as pipeting,...) in lab, oral exams, or written exams.
comments:
As commonly used in conventional labs, some methods (such as grading labwork, discussions, and reports) may tend to counteract the DB advantages discussed earlier. But if simultaneously being a judge and teacher doesn't diminish the effectiveness of teaching (I can't combine these well, but maybe other TAs could), it could be feasible to grade labwork (but this may discourage questions) and discussions (and this could encourage active participation). / If written reports are designed cleverly, so the questions being asked are extensions or variations of what is being discussed, a main function of DB -- to help students prepare for later applications of what they're learning -- could have involve an application in the very near future, and this could encourage attention during discussions. { But in this situation a TA must be careful about providing "equal information" to all students, so the use of inquiry instruction would be more difficult and less likely. }
Appropriately used, accountability (qualitative or quantitative) and skill exams are very compatible with DB.
Oral exams can be excellent, but only if they're done well. This is difficult when using TAs with a wide range of abilities and experience, but it might be practical when all labs in a course are taught by one person, or if multiple TAs are all skilled at giving oral exams. { But there may be a problem with "information leaks" since the exams won't be given simultaneously. }
An increased use of written exams (that test the concepts and skills we want students to be learning in lab) deserves careful consideration:
A written lab exam can ask questions ranging from simple data analysis to familiar algorithmic problems to novel problems that require high-level thinking and creative improvisation.
An exam to test thinking skills should: differentiate between levels of mastery by including problems that vary in difficulty (with some problems that most students solve, some only a few solve, and some in between); provide an accurate measure of thinking skills; and measure the appropriate skills, the ones we're trying to teach (there should be a high correlation between success on problems and a mastery of thinking skills that have been the focus of learning in labs). Achieving all of these goals is not easy, but the potential rewards make it a challenge worth pursuing. { comment: These goals are common in professional test design. For example, scholars constructing the American Chemical Society Exams for an overall course (not just for labs) are trying to satisfy similar criteria. }
By making minor variations (changing numbers, chemicals,...) on familiar themes, it is easy to test for skills in data analysis, or to write algorithmic problems. But it is difficult to construct an exam that provides a reliably accurate measure of higher-level thinking skills, to invent novel problems that test creative and critical thinking. This requires creatively critical thinking by the exam writers, and this takes time. Therefore, especially in a small department, we should ask whether the "benefit per student" per hour invested (in making new problems each semester) is worth the effort. { Buying problems from test-writing specialists would require getting a match between the DB labs and the externally supplied problems, which might be time-consuming and expensive. }
Why do we need new problems? Because all questions from old exams should be available to all students, to improve the justice in grading by eliminating the advantage for students who have access to test files from a fraternity, sorority, dormitory, instructional center, athletic department, or tutor. Therefore, new problems are necessary. { But on a new exam, including some old problems (verbatim or with variations) can be useful to motivate students so they will study the old exams, and to decrease the number of new problems that must be written. }
In a department with many sections that share the same labs and the same new lab exam, all students should take the exam simultaneously, to avoid a leaking of information from students who see the exam earlier. Also, to preserve security the TAs should not see a new exam until the students see it; TAs should "teach to the exam" by knowing the general type of questions (similar to those on previous exams) but if they know the specific questions there will be unavoidable ethical dilemmas about what to teach.
a summary of potential problems with DB and grading: We should consider the possibility that decreasing the emphasis on "direct grading" of labs may increase the quality of learning, for reasons discussed earlier. Instead of using non-DB labs so we can grade students on what they do in lab, maybe we can use DB labs to help students prepare for future applications of what they are learning, later in the course and in life.
LINKS TO RELATED PAGES:
Aesop's Education for Goal-Directed Education
Thinking Skills in Labs — Chemistry Examples
original (from 1999) Home Page for "Thinking Skills in Chemistry Labs"
original (from 1999) full-length version of Discussion-Based Labs
DesignMethod & Scientific Method in Thinking Skills Education