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THE NATURE OF SCIENCE
Science is the investigation and exploration of natural events and of the new information that results from those investigations. Science, like all disciplines uses a system of rules to guide its practice. Scientists have developed many tools and methods for working within the rules of science. These scientific rules, tools, and methods are known collectively as the nature of science.
THE PRACTICE OF SCIENCE
Many people instantly think of experiments when they think of science. However, while experiments are an important method of doing science, they are not the only way for scientists to investigate a question. There are several different types of scientific investigations, including controlled experiments, systematic observations, and data set analysis. Scientific investigations provide a way for researchers to use a systematic approach to answer questions about the natural world. Certain scientific questions lend themselves more toward certain types of investigations, so it is important for us to be able to distinguish between them. This review will focus on two of the more common types of investigations, controlled experiments and systematic observations.
A controlled experiment is a scientific investigation that tests how one factor affects another. A key step in conducting an experiment is to identify any factor that can be changed which may affect the outcome of the experiment. Such factors are called variables. In a controlled experiment, it is important to identify three types of variables. The first variable, the independent variable (test variable), is the factor that you want to test. It is the variable that you are manipulating to see what affect it has on something else. The second variable, the dependent variable (outcome variable), is the factor that you will observe or measure to see how it is affected by the independent variable. These two variables are the only ones that should change for any of your samples; all other factors should remain the same during your investigation. Variables that are kept the same for all samples are called controlled variables, or constants. Keeping them constant allows you to conclude that any variations in the dependent variable are a result of the independent variable changing. If you did not control these other variables, then you would have no way of knowing whether changes in the dependent variable were caused by the independent variable or one of these other factors.
A systematic observation is a scientific investigation that seeks to determine relationships between various factors by observing the interactions between them. It is a more “passive” way for scientists to learn about a topic without manipulating their environment the way they would in a controlled experiment. Scientists often establish a set of procedures or rules to govern their observation to eliminate bias, a process where the investigator knowingly or unknowingly influences the results. A systematic observation is based on the science process skill of observing. An observation is the result of using one or more of your five senses to gather and record information. It should not be confused with an inference, which is the process of using prior knowledge or experience to provide a logical explanation for an observation.
Before beginning an investigation, it is often necessary to make a hypothesis because it can help you develop your guiding question. It is important to understand that a hypothesis is different than a prediction. A hypothesis is a testable statement; an explanation that can be tested by performing the investigation. A prediction is a statement that represents the expected outcome of the investigation. A hypothesis is made at the beginning of the investigation so it can help you develop your guiding question and methods, while a prediction is made after your methods have been established but before you have collected any data. The prediction is often used to test the hypothesis. Many investigations are designed so that if the hypothesis is correct, then the prediction will be observed.
The information you gather during an investigation is called data. There are two types of data, qualitative data and quantitative data. Qualitative data uses words to describe what is observed, while quantitative data uses numbers to describe what is observed. In order for data to be useful, it must be analyzed. Data analysis includes finding patterns, highlighting relationships, and identifying trends among the observations and measurements you have collected. The purpose of analyzing data is to form a conclusion, or answer to the guiding question of the investigation. Your conclusion must be supported by the data. Data that is used to support a conclusion is called evidence. Scientific evidence is the foundation of all scientific knowledge.
THE CHARACTERISTICS OF SCIENCE KNOWLEDGE
Scientific knowledge represents ideas that are widely accepted throughout the scientific community. It is the result of continuous study, testing, debate, and confirmation of these ideas. Scientific explanations must be based on the empirical evidence, the cumulative body of observations on a scientific topic. They must also stand up to scientific confirmation.
Scientific confirmation is the process of attaining consistent and predictable results through investigation. This is done in two ways, repetition and replication. Repetition occurs when a scientist performs multiple trials in an investigation or repeats an investigation multiple times. Replication occurs when different scientists perform the same investigation. In both cases, the investigators are looking for results that are consistent and predictable, meaning that each investigation should yield similar results.
It is important to understand that confirmation does NOT mean to “prove” an idea or that the results of an investigation are “correct”. In fact, it is a common misconception that scientists prove anything. The reason that scientists cannot “prove” an idea is that, by definition, scientific knowledge is the result of continuous testing, debate, and confirmation. If it is a continuous process, then it is never finished; meaning that science cannot state that it has arrived at a “final” answer. To say that an idea has been “proven” gives the impression that it is not open to change. On the contrary, scientific knowledge is tentative, meaning that it can change if new evidence surfaces that contradicts current understanding. This ability to change scientific explanations is an important characteristic of science. History is full of examples where scientific knowledge changes to fit newly discovered evidence.
THE ROLE OF THEORIES, LAWS, HYPOTHESES, AND MODELS
Scientific Knowledge consists of many theories and laws. Unfortunately, scientific laws and theories are misunderstood by a significant portion of our society, and even by some within the science community. Many people hold on to the misconception that a theory is an unproven idea while a law has been proven correct. Recognizing the actual meaning and role of scientific laws and theories is essential to understanding the nature of scientific knowledge.
A scientific law refers to a rule that describes a repeatable pattern in nature. It does not attempt to explain why the pattern exists or how it happens; a law is simply a statement that it will happen every time under a specific set of conditions. Scientific laws are useful because they allow scientists to make assumptions of truth about specific patterns. A law is considered to be “true” until an observation is made that does not follow the law.
While scientific laws are not concerned with why a pattern exists, that doesn’t mean that scientists aren’t interested in “why”. Much of the work of science is an effort to explain such patterns. This is why hypotheses are important. A hypothesis is a possible explanation of “why”. When a group of closely-related hypotheses are confirmed through a significant amount of repetition and replication, it is possible to develop them into a scientific theory. A scientific theory is an explanation of observations or events that is based on a significant amount of research, debate, and confirmation. Scientific theories are important because they help us explain our world. They give us a foundation of knowledge to build on. However, as discussed above, scientific knowledge is tentative. This means that both theories and laws can be rejected or modified. If new evidence is discovered that disproves a theory, the theory can be changed to fit the new evidence. Theories are rarely discarded completely, but rather, they are tweaked so that they agree with the empirical evidence.
Another common misconception about scientific theories is that they will become law when they are proven correct. This is wrong! A theory will NEVER become a law; just as an apple will never become an orange because they are two different things. Laws describe what happens in nature, and theories explain why things happen.
It is often difficult for scientists to explain their ideas to people outside of their field of study. Many scientific theories are so complex that the average person cannot fully understand them. In situations like this, scientists often use models to communicate their ideas. A scientific model is a representation of an idea, object, system, or process. Scientific models have two main purposes. Some models are used to help scientists think about a phenomenon that either cannot be directly observed (such as atoms) or would be too dangerous, expensive, or difficult to observe directly (such as solar fusion). Other models are used to simplify a scientific concept so it can be more easily understood by the average person. In this way, models are valuable tools in deepening and expanding scientific knowledge. Models can include 3-dimensional representations of objects, drawings or diagrams, flow-charts, analogies, mathematical equations, or any other way that one might represent an idea, object, system, or process.
TECHNOLOGY
Educating the public about scientific concepts has become increasingly important in the modern era. As our knowledge increases, society continues to develop new materials and make significant advancements in technology. Technology is the practical use of scientific knowledge, especially in the case of industrial and commercial uses. Consider this… In 1944 the first “digital” computer was built at the University of Pennsylvania. It weighed almost 100,000 pounds and took up an entire 800 square-foot room. Just 50 years later, in 1994, personal computers fit on a small table in the homes of millions of people. The size of a few large textbooks, these computers were used by the general public for gaming and internet browsing. Less than 25 years later, the smart phone in your pocket has more versatility and computing power than most of those PC’s. Technological advancements such as this not only make it easier to study new phenomena, unearth new discoveries, and perform ever-more complex calculations, but it is becoming increasingly easier to communicate those ideas to a global audience.