Improving Class Interaction

Any Questions?
(Richard Felder, Chemical Engineering Education, 1994)

If I ask the whole class a question and wait for someone to volunteer an answer, the students remain silent and nervously avoid eye contact with me until one of them (usually the same one) pipes up with an answer. On the other hand, if I call on individual students with questions, I am likely to provoke more fear than thought.

No matter how kindly my manner and how many eloquent speeches I make about the value of wrong answers, most students consider being questioned in class as a setup for them to look ignorant in public—and if the questions require real thought, their fear may be justified.

I find that a better way to get the students thinking actively in class is to ask a question, have the students work in groups of two to four people to generate answers, and then call on several of the groups to share their results. I vary the procedure occasionally by having the students formulate answers individually, then work in pairs to reach consensus. For more complex problems, I might then have pairs get together to synthesize team-of-four solutions.

Following are some different things we can ask our students to do that can get them thinking in ways that "Given this fact, calculate that" never can.

Define a concept in your own words

Using terms a bright high school senior or your grandmother could understand, briefly explain the concept of vapor pressure (viscosity, heat transfer coefficient, ideal solution, etc.).

Explain familiar phenomena in terms of course concepts

Why do I feel comfortable in 65-degree still air, cool when a 65-degree wind is blowing, freezing in 65-degree water, and even colder when I step out of the water unless the relative humidity is close to 100%?

Predict system behavior before calculating it

Without using your calculator, estimate the time it will take for half of the methanol in the vessel to drain out (for all the water in the kettle to boil off, for half of the reactant to be converted).

Think about what you've calculated

Find two different ways to verify that the results you have calculated are accurate or that the formula you have chosen to solve the problem is the correct one. The computer output says that we need a tank volume of 3,657,924 cubic meters. Any problems with this solution?

Brainstorm

What are possible safety (environmental, quality control) problems we might encounter with the process unit we just designed? Once a list of problems has been generated, you might follow up by asking the students to prioritize the problems in terms of their potential impact and to suggest ways to minimize or eliminate them.

Formulate questions

Write on an index card two questions you could ask a classmate to verify that he or she read and understood the assigned material for today's class.