Dedicated to the teaching of Earth Sciences


Prof. Sean Tvelia Suffolk County Community College


The Scientific Method

In this class you will be expected to not only learn about important processes and events but also be able to apply what you know to determine what the Earth may have looked like millions, and even hundreds of millions of years ago. This means that for most of this class I will be asking you to think like a scientist and determine what the world looked like based on evidence preserved within the rock record. To do this you will need some basic background on geologic processes--which we will get to-- but you will also need to understand how the scientific method works.

Geology isn't a guessing game. Like all other sciences, geology relies on a systematic approach to answering specific questions about world. We call this approach the scientific method. The scientific method is not a recipe for an answer but it is a process by which you can arrive at a logical conclusion to a problem

In all cases the scientific method begins with a question.For example, what makes material burn? Once a specific question is identified scientists can begin collecting data to help answer the question. Data can come in many forms depending on the complexity of the question being asked; It can be simple visual observations or it can be very precise measurments of properties like temperature and pressure. Once a enough information has been colected a hypothesis can be developed. A hypothesis is simply an idea that helps explain a set of observations; in the scientific method the best hyothesis is one that can be tested through careful experimentation. In other words it can be either validated or invalidated.

Take for example my previous question, what makes material burn? In the mid seventeenth century chemists were trying to answer this very question after observing that most metals when burned turn into a white powder called a calx. Then when heated with charcaol the clax can be turned back into the original metal. To explain this, scientists hypothesized that all things must contain a previously unkown element known as pholgiston and it was the varying amounts of phlogiston that lead to the different properties of earth materials.
When a metal burned it actually released its phlogiston to the air. Since this changed the amount of phlogiston within the material it also changed the properties of the material. Silvery magnesium when burned turned into a white powder. When burned in charcoal, it was believed that, the calx simply absorbed the phlogiston given off by the burning charcoal and reverted back to the former metal.

To test this hypothesis a number of experiments were devised. First, if burning a metal released pholigstion into the air then it seems reasonable to expect that when burned a metal should become lighter as it gives off more and more phlogiston. Unfortunately the experiments showed the exact opposite. A calx always weighs more than the original metal.

Meanwhile, Antoine Lavosier, a wealthy french aristocrat, devised another experiment. He reasoned that if he burned a calx then the clax should absorb phlogiston from the air, revert to its previous metal and become heavier. Unfortunatel, again experiments proved the exact opposite. When Lavoisier used his giant lenses to heat the calx he made two observations. First, the calx became lighter and second the calx also seemed to give off what Lavoisier called "fixed air."

Through these simple experiments Lavoisier was able to disprove the phlogiston hypothesis. Although not exactly correct Lavoisier developed a new hypothesis based on his observation. He claimed that by burning metal it was combined with this "fixed air." This is why the calx was always heavier. Then by burning the calx Lavoisier premised that he was simply releasing the fixed air.

Science assumes the natural world is consistent and predictable. Therefore our goal is to discover 'patterns' that we can then use to make predictions. If a hypothesis is validated it can then be used to develop laws and theories. Laws are models that explain specific observations and can be used to predict certain behaviors, such as the affect of gravity on a falling ball. Theories on the other hand are general explanations for the characteristics and behavoir of the natural world. In laymans terms, laws describe what will happen and theories describe why.

Chapter Contents:

1.0: The Science of Geology

1.1: Geology Through Time

1.2: The Scientific Method

1.3: The Big Bang

1.4: The Solar System

1.5: The Earth

1.6: The Earth System