Geology For Dummies - Alecia M. Spooner

Скачать книгу

This type of graph is best used for illustrating different pieces of a whole. The total of a pie chart must always add up to 100 percent.

       Bar graph: Also called histograms, bar charts are used to display information that can be sorted into different categories.

       Scatterplot: Scatterplot graphs illustrate how two types of data are related. Sometimes a scientist will use a scatterplot to look for patterns of relationship between the data types — by finding clusters of data points.

       Line graph: This type of graph is most commonly used to plot changes in a type of data over time, distance, or other variable.

Schematic illustration of a) Pie chart, b) Bar chart, c) Line graph, and d) Scatter plot.

      Interpreting results

      After data has been described, compared, and graphed, the next step is interpreting the data to draw new conclusions and perhaps propose a new hypothesis for further testing. Often scientists will find that the patterns in their data bring up new questions for exploration.

      

If an experiment is designed well, the outcome (and collected data) should clearly prove or disprove the initial hypothesis. It is much easier and more common for a scientist to prove a hypothesis wrong than to prove it right. Finding that the hypothesis is incorrect helps rule out wrong ideas and is a very important step toward eventually finding an answer to larger questions that are being asked — and toward determining which hypothesis to test next.

      The challenge at this stage is applying previous knowledge (perhaps from previous experiments) to understand what the patterns in the data — or the relationships between variables — mean. Rather than finding answers to all the questions, scientists often find themselves asking new questions and circling back to the hypothesis stage, preparing to test another hypothesis.

      Sharing the findings

      When a scientist has completed experiments, analyzed data, and interpreted the results, he must share his findings and ideas with other scientists. Commonly this step is done through scientific journals that are peer-reviewed, meaning that other qualified and respected scientists have examined the experimental design and procedure, perhaps tested it themselves, and determined that the results and interpretation are reasonable.

      The peer-review step is very important. The process of having other knowledgeable scientists — other specialists in a particular topic — double-check the work helps find any errors. Errors may lead to false results or incorrect interpretations. Having more than one eye look for errors reduces the potential for moving forward on such false assumptions.

      The goal of scientific study is to better understand the world. Step by step, information is collected until a broader or deeper understanding is gained. Eventually, this understanding may be expressed as a scientific theory. As scientists create and share theories, they expand what we know about the world around us.

      It’s never “just a theory”

      Most people use the word theory to refer to an educated guess — a hypothesis. But scientifically speaking, a theory explains how some complex process works in the natural world. For example, the theory of plate tectonics that I cover in detail in Chapter 10 explains how crustal plates on the earth move around, forming mountains and volcanoes and causing earthquakes. The theory explains how all those geologic processes and resulting features are related to one another through the movement of crustal plates.

      

A theory does not, however, explain why something occurs. The theory of plate tectonics does not answer the question of why the surface of the earth is broken into plates that move around. It only describes how those plates move around and interact with one another to result in the features we observe.

      When a scientist describes something as a theory, she has come to the end of a long series of experiments and hypothesis testing. She is able to explain something so well, to provide evidence for that explanation (and to have that something accepted by other scientists as true) that it can be called a theory.

      

In other words, a theory is a hypothesis that has been thoroughly tested through multiple experiments and is accepted as true by the scientific community. But the work doesn’t end there! Scientists will continue to test hypotheses about the details within a theory, filling in gaps in understanding and looking out for incorrect assumptions that can be corrected to strengthen the theory.

      Scientific theory versus scientific law

      Scientific theories are not waiting to blossom someday into scientific laws. Laws and theories in science are two very different things.

       A scientific law describes an observed action that, when repeated many times, is always the same. For example the law of gravity states that two objects will move toward one another. This movement is observed every time you drop something. The object you drop is attracted to the earth. The law of gravity simply describes this action, which is demonstrated to be the same in every test.

       A scientific theory explains how a set of observations are related. For example, the theory of gravity seeks to explain how the relationship of two objects (their relative size, weight, and distance from each other) results in the observed interaction described by the law of gravity.Both a scientific law and a scientific theory could be accurately described as “fact.” Both are developed out of hypotheses that have been tested and proved true. A well-tested and generally accepted theory is considered true even though it may still be tested by the proposal of new hypotheses and experimentation. In some cases, part of a theory may be shown to be untrue, in which case the theory will be adjusted to accommodate this new truth without the entire theory being called into question.

      The road to paradigms

      A really thorough, well-tested, and widely accepted theory may become the current scientific paradigm. Scientific paradigms are patterns that serve as models for further research. Right now, plate tectonics theory is the paradigm within which all new geologic research takes place. The explanation provided by plate tectonics theory is accepted as proven true, and most researchers seek to answer questions that refine their understanding of this process rather than seeking to disprove the theory as a whole.

      Paradigms, like theories, may change with new information; the change is called a paradigm shift. A paradigm shift brings a new perspective — a whole new way of looking at things. For example, the acceptance of the ancient age of the earth was a paradigm shift for early geologists. These scientists had struggled to explain how geologic features were created in the short span of a few thousand years (previously accepted as the age of the earth). The new paradigm of Earth being billions of years old provided a framework within which geologic processes had plenty of time to occur, creating the features they observed. (See Chapter 3 for more discussion about this particular paradigm shift.)

      As with many

Скачать книгу