Tutorial round 7: Assignment for the nature of heat

Reading assignment: “Heat is a Form of Motion: An Experiment in Boring Cannon” Download it from here.

For this round of tutorials, the reading assignment is on the internet. Please download it from the link above. It is about 5 pages of text, depending on your printer. The reading assignment is the text of a journal article published in 1798 by Benjamin Thompson, who took the name Count Rumford when he moved to Germany. He was discussed briefly in class on Wednesday, January 10, and his work in the boring of cannons was described then. In this article, Rumford described his observations of what he saw going on during the process of cannon boring and some experiments he undertook that bear upon the nature of heat.

You will recall from my lecture, that chemists working around this time were endeavouring to reconstruct chemistry as a science that fit the mechanical model that they believed how scientific theories must be conceived. A particular problem for the early chemists was the nature of heat. Was it an element, like carbon or oxygen, or was it something else. Mechanical models required that all components of the theory be quantifiable. Heat fit that. Particular, measurable amounts of heat had to be added to chemical elements to cause certain reactions to take place, and some chemical reactions produced heat, also in measurable quantities. But what was heat? Was it some form of matter, like the chemical elements, or was it the other possibility, some form of motion.

Rumford thought he had the answer: heat was motion, and he concluded that on the basis of the obversations he described in this article.

Your task for this tutorial is to analyze his argument from the point of view of scientific discovery and scientific method, as we have discussed in class. Think about the following and provide your answers as starting points for class discussion:

1. Was Rumford in a special position that gave him the insights to make his discovery (i.e., educated guess) that heat was motion and not a fluid? Compare Rumford’s position to Archimedes with the crown problem and Kekulé with benzene.

2. Having made his hypothesis, how did Rumford test it? How did his tests fit the model of modus tollens and/or the fallacy of affirming the consequent?

3. What did Rumford establish by his article? Did he show that heat must be a form of motion or did he show (only) that it cannot be a material fluid? Or did he establish any of these assertions?