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Class Notes
Science for inquiring minds
(Published May 20, 2002)

By H. WELLS WULSIN

Last week, "Darryl" jumped from being the worst student to the best student in a single day. He has received F's for the first three quarters of introductory chemistry, and last quarter he was absent from class twice as many days as he was present. I ran out of ideas long ago for what could be done to turn him around.

We were studying a unit on gases, and the topic for the day was Boyle's Law, which says that the volume of a gas is inversely proportional to the pressure exerted on it. I wanted students to see Boyle's Law in action, so I had each student bring in a two-liter bottle in order to create what is known as a "Cartesian diver." The only other material required for this science experiment is a medicine dropper, which I provided.

Creating the diver is simple: the dropper is filled halfway with water and placed inside the two-liter bottle, which is full of water. As expected, the air inside the dropper causes it to float, but when the bottle is squeezed, the dropper dives to the bottom. The students had no instructions for how to design the diver, but had to use trial and error to find the optimum amount of water to put in the dropper. Some filled the dropper with too much water, causing it to sink, while others put no water in the dropper, making it too buoyant to dive.

I offered a candy bar to the student whose diver could complete five round-trip dives the fastest. I timed each student with a stopwatch, announcing new records as they were set. Each time the record was broken, a victory cheer was met by groans of disappointment from others. The lowest time was finally set by Darryl, clocking in at 8.2 seconds. "I'm the champion!" he exclaimed triumphantly, two fists raised in the air. Before receiving his prize, Darryl had to explain the diver's motion using Boyle's Law - which he did flawlessly. I wondered to myself: Was this really the same student who hadn't taken any notes during our whole unit?

These are the moments that I live for as a science teacher. It is a joy to watch students solve a problem not because it will count for a grade, not because their teacher has coerced them, but simply because they are curious and want to figure it out. (It doesn't hurt to offer a little candy as incentive.)

Research has shown science educators that students learn best when they are active learners: building a catapult, testing enzyme catalysts, separating oil from water. The mind is more engaged when there is an immediate, tangible problem to solve, and this kind of curiosity is critical to developing the ability for scientific thinking. "Inquiry-based learning" is the name for science instruction in which students are responsible for discovering scientific principles by performing independent experiments. Done right, it has the potential to get even the least-disciplined students eager to learn about science.

We have been able to do some other inquiry-based experiments this year. To study Newton's Third Law of Motion ("For every reaction, there is an equal and opposite reaction"), I asked groups of students to move a balloon across the room as quickly as possible, using only a drinking straw, a long piece of string and masking tape. To learn about force and impulse, physics students built egg-carrying devices to cushion an egg dropped onto concrete from the top of the stadium bleachers. When studying simple machines, we calculated the mechanical advantage of different gears on my 10-speed bicycle.

Unfortunately, planning engaging inquiry-based classroom activities is sometimes difficult. These activities require supplies and resources that may not be available. Also, involved activities require a significant amount of time for planning. Sometimes there are just not enough hours in the day to plan as well as one would like.

On May 15, I had to substitute for another teacher during my planning period, so I didn't have time to type up a daily agenda for physics. When I came into my classroom the next period, it was clear that I was not as prepared as usual. There was no agenda on the overhead, and I had to hastily write four recap questions on the chalkboard. It took me a few precious minutes at the beginning of class to decide what topic in our electricity unit to teach.

Certainly the students learned something by the end of the period, but there was no hiding the fact that this was a class thrown together at the last minute. I have access to a wealth of resources for lab ideas - veteran teachers, university and public libraries, and a high-speed internet connection - and I know there are lots of mind-engaging activities we could be doing. However, the reality I have discovered is that teachers (especially in their first year) often don't have the time to develop as exciting lessons as they would like to.

It would be much easier to fill my class time by giving lectures or handing out worksheets to complete. It would save me many hours of planning and would eliminate the need for funding to buy new supplies. But when inertia and fatigue pull me towards the easy lesson plan, I remind myself of all the students whose minds will be energized if they can only get a chance to learn science in an interactive way.

In the end, it's not only students like Darryl who benefit, since even straight-A students need to solve practical problems using their scientific knowledge. When I fall short of the ideal inquiry-based lesson plan, I hope my students forgive their teacher for being less than perfect. After all, I allow my students to be less than perfect in their laboratory work - so long as they explain all of the experimental error in the write-up!

***

H. Wells Wulsin is a first-year chemistry and physics teacher at the H.D. Woodson Academy of Finance and Business. Please send comments and questions to wulsin@gwu.edu.

Copyright 2002, The Common Denominator