Chemistry Professor Encourages
cience texts should respond to their readers, says Carl David, and should refuse to allow a reader to proceed until the reader has demonstrated understanding of the material.
"This is the future of technical books," he says. To learn from a technical book, he says, students must follow each step in the reasoning. If they are required to answer questions as they work through the text, he says, they will learn how to read such a book.
David, a professor of chemistry, has put his idea to the test in his graduate class on quantum mechanics. He has posted the required reading material to the Web, and students must correctly answer questions on one portion before proceeding to the next assignment.
Pam Dolan, a graduate student in chemistry, says the computer-assisted readings in David's class help her digest the material. "The computer-aided readings force one to pay attention to many of the nuts-and-bolts mathematics inherent in a rigorous study of quantum mechanics," she says. "It is easy to 'fall asleep at the wheel' while reading about these details in a traditional textbook. With Dr. David's method, you cannot gloss over derivations, because the program will not let you continue with the reading until you can prove you understand the math."
Tom Terry, an associate professor of molecular and cellular biology, has tried something similar. Last year, he also used the Web to administer quizzes on the assigned reading in one of his classes. He says students responded well to the quizzes because the approach forced them to keep up with the readings.
David also wants to change the nature of science tests. He says chemistry exams should not include multiple-choice questions and should be administered over the Internet.
Multiple-choice questions are a poor way to measure a student's understanding of science, he says, because the creator of a multiple-choice test intentionally tries to distract the student from the right answer. "They're more a test of reading than of science," he says. "Multiple-choice is intentionally deceptive."
It is fairer, David says, to require the students to construct the answers themselves by doing a calculation or drawing a diagram. If a student gets the right answer, he grants full credit. If not, he grants no credit.
The Internet would allow professors to make exams available whenever students are ready to take them. It also could offer students the opportunity to take an exam multiple times.
David says electronic exams are the way of the future, although there are still problems in administering exams over the Web. Currently, he says, there is no way to verify the identity of a person taking an exam over the Web, for example. "But in the future, my grandchildren will be tested this way," David says.
In the meantime, he is forging ahead with the use of computers in teaching freshman chemistry and has written hundreds of web-based homework and pre-lab problems for his chemistry courses.
Using a browser, a student can read David's problems, submit answers, and get hints. The professor's computer automatically checks each answer and responds to the student, without any human intervention.
The problems are a good way to learn the material, David says, and his students agree. "I like it because the problems he puts on the Web are like the problems he puts on tests," says Kelly McCabe, a fourth-semester math major. "It's a good way of studying."
David says the purpose of his techniques is to help students be independent thinkers. "Most of the responsibility for learning is on the students." And that, he adds, is what a university education is all about: "The point of the university," he says, "is to wean students off teaching."
David is trying to equip his students to succeed in an era when more and more knowledge is available.
"I want them to be better than I was," he says. "I want them to learn the material faster and better and then move on. The amount of knowledge is advancing, but the number of years in school is fixed."
He says he is confident students can meet the challenge: "If you raise the bar, students will respond by doing better."
Brent C. Evans