Making Science Real

......Teaching and learning science in the real world

From the Scientific Method to Claim Evidence Reasoning

Cosmogenic Theory

Since recorded time, humans have been curious about the natural world. They observed phenomena and sought explanations for what they saw.  How is scientific knowledge developed? How is this knowledge changed as scientists find new evidence?

We all remember earth, wind, fire, and air, right? (Or maybe just Earth Wind and Fire, depending on your age.)

TL;DR: Two millennia ago, the Greek philosopher Empedocles proposed the cosmogenic theory of 4 elements. In 1667, J. J. Becher suggested Phlogiston theory, later put together more formally by Georg Ernst Stahl. Phlogiston theory attempted to explain chemical processes such as combustion and rusting, now collectively known as oxidation. The Phlogiston theory explained these processes by the release of a substance called phlogiston while burning and the absorption of phlogiston during reverse processes.

     Over time, newer explanations may upend older ideas as more sophisticated equipment and methods allow the collection and analysis of newer, more reliable evidence.  The theory was challenged by evidence showing the increase in mass of the substance rather than a decrease in mass,  after combustion. This evidence, combined with the work of Anton Lavosier and others in the discovery of oxygen  led to the phlogiston theory being abandoned before the end of the 18th century.

     Let’s stop for a moment to examine the pattern we see in this example. First, scientists attempt to explain their observations with the best knowledge and data they have. Years pass; instruments and technology develop. Using new technology, observations are made and data are collected in ways that were not possible before. How does this new information fit the old explanation? Often, it doesn’t. New explanations are needed and are proposed.

     Valid, reliable evidence has become the foundation of scientific discoveries. The processing of evidence and explaining the evidence with respect to what is already known is the foundation of communicating new information.  Enter: Claim, Evidence, Reasoning, commonly referred to as CER, has emerged as the fundamental goal of science.

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