Wednesday, June 3, 2009

Changeless Physical Laws

Our recent posts on physical constants take me back several decades in my teaching career. One summer, after returning from a trip to the western states, I discovered the district science chairman had lined up a workshop for science teachers in my region. A course called “Introductory Physical Science” had just been developed for use as an 8th or 9th grade offering. Its goals and concepts were lofty and ahead of the curve in science education. Lawrence S. Lerner, science author and textbook critic, offered this appraisal of the IPS course in 1999: “The authors of Introductory Physical Science show the student how science is done, and they teach the student to think like a scientist. Their strategy…is to take the student through a series of experiments and analyses that amount to an abridged account of the development of chemistry and physics from the mid-1700s to 1900 or so.” From my experience, I agree that the IPS course helped students “think like a scientist.”

The experiments were carefully structured and sequenced to accomplish that goal. An offensively odorous introductory experiment on the destructive distillation of wood successfully captured the interest not only of our class members, but also everyone else at our end of the building. Then the students, in pairs, launched into a series of five varied experiments. Those activities purposed to demonstrate that, regardless of other apparent and significant changes occurring, the mass of matter in the isolated chemical system at each table was completely conserved. The changes involved dissolving a solid in a liquid, freezing and melting, generating a gas by adding a solid to a liquid, and two spectacular chemical change experiments in which new compounds were formed: a bright yellow solid precipitate formed by mixing two clear solutions, and another reaction generating intense heat, a red-hot glow, and production of an obviously new substance when two powdered solids were mixed and heated.

Beyond much doubt, we discovered that mass was completely conserved. We carefully measured the masses of the systems before and after. We accumulated results from as many as fifty pairs of experimenting students for each of five different types of chemical events. The blackboards were filled with experimental data, student-crafted bar graphs displayed our derived results, and we discussed possible errors and what our results could mean--all of this contributed to a sense of student satisfaction that they were actually discovering for themselves the important principles which would trigger further questions and experiments. After the complete year of IPS, students possessed an experimental justification for concluding that matter is composed of particles. This concept was only imagined by ancient thinkers, and only proven convincingly by scientists in the last two or three centuries.

In our recent posts we have spoken how precisely the masses of some of these particles have been determined in the last few decades. Masses of the proton, neutron, and electron are known to one or two parts per million. Experiments such as those carried out by IPS students (as well as high-tech science laboratories) have shown that the mass of everyday matter is invariant; it is conserved. The conservation of matter is now a scientific law based on plentiful observations of the way our universe operates under every conceivable circumstance.

It would seem that if the Creator of Heaven and Earth caused matter to operate according to what we might call absolutes, we might also devote some thought to the Creator’s absolutes in the moral realm: “I the Lord do not change” (Mal. 3:6 NIV). There is a rational connection between the operation of our physical world and the operation of behavioral moral absolutes. In this relativistic post-modern culture, we must contemplate this harmony in the physical and moral spheres.