BIO 111, The Scientific Method

Once a hypothesis has been selected, a prediction may be made. A prediction is similar to a hypothesis but it typically has the format "If . . . then . . . ." For example, the prediction for the first hypothesis might be,

"If the student turns on the air conditioning, then the classroom will no longer be too warm. Notice that the portion of the statement after the word "then" indicates what will be observed if the hypothesis is correct.

In other words, plants treated with all three brands of fertilizer should have the same amounts of water and sunlight to prevent these variables from interacting with the independent variable of interest.

A control group is a part of the experiment that does not change and provides a baseline of comparison to determine the effect of the independent variable of interest on the dependent variable.

Hypotheses, or tentative explanations, are generally produced within the context of a scientific theory.

A scientific theory is a generally accepted, thoroughly tested and confirmed explanation for a set of observations or phenomena.

Recall that a hypothesis is a suggested explanation that can be tested. To solve a problem, several hypotheses may be proposed. one hypothesis might be, "The classroom is warm because no one turned on the air conditioning."

But there could be other responses to the question, and therefore other hypotheses may be proposed. A second hypothesis might be, "The classroom is warm because there is a power failure, and so the air conditioning doesn't work."

Reporting Scientific Work Whether scientific research is basic science or applied science, scientists must share their findings for other researchers to expand and build upon their discoveries.

Communication and collaboration within and between sub-disciplines of science are key to the advancement of knowledge in science.

The process of peer review helps to ensure that the research described in a scientific paper or grant proposal is original, significant, logical, and thorough.

Grant proposals, which are requests for research funding, are also subject to peer review.

There is not an evolution of hypotheses through theories to laws as if they represented some increase in certainty about the world.

Hypotheses are the day-to-day material that scientists work with and they are developed within the context of theories. Laws are concise descriptions of parts of the world that are amenable to formulaic or mathematical description.

The scientific method is a series of defined steps that include experiments and careful observation.

If a hypothesis is not supported by data, a new hypothesis can be proposed.

Just adding something is also a control against the possibility that adding extra matter to the pond has an effect.

If the treated ponds show lesser growth of algae, then we have found support for our hypothesis.

A flow chart shows the steps in the scientific method. In step 1, an observation is made. In step 2, a question is asked about the observation. In step 3, an answer to the question, called a hypothesis, is proposed. In step 4, a prediction is made based on the hypothesis.

In step 5, an experiment is done to test the prediction. In step 6, the results are analyzed to determine whether or not the hypothesis is supported. If the hypothesis is not supported, another hypothesis is made. In either case, the results are reported.

In human drug trials, it is common for the control group to be given a placebo "sugar pill") so that individuals both groups experimental and control) are taking a pill. Otherwise, the act of taking a pill would be a variable that wasn't controlled.

It is also common for neither the subjects nor the researchers directly working with them to know which group is receiving the placebo. This feature of experiments, called a double-blind design, is included to prevent any bias from influencing the results.

In practice, the scientific method is not as rigid and structured as it might at first appear. Sometimes an experiment leads to conclusions that favor a change in approach; often, an experiment brings entirely new scientific questions to the puzzle.

Many times, science does not operate in a linear fashion; instead, scientists continually draw inferences and make generalizations, finding patterns as their research proceeds. Scientific reasoning is more complex than the scientific method alone suggests.

The scientific process typically starts with an observation (often a problem to be solved) that leads to a question. Let's think about a simple problem that starts with an observation and apply the scientific method to solve the problem.

One Monday morning, a student arrives at class and quickly discovers that the classroom is too warm. That is an observation that also describes a problem: the classroom is too warm. The student then asks a question: "Why is the classroom so warm?"

The Nature of Science Biology is a science, but what exactly is science? What does the study of biology share with other scientific disciplines?

Science from the Latin scientia, meaning "knowledge") can be defined as knowledge about the natural world.

These include such things as answering purely moral questions, aesthetic questions, or what can be generally categorized as spiritual questions.

Science has cannot investigate these areas because they are outside the realm of material phenomena, the phenomena of matter and energy, and cannot be observed and measured.

Scientific Inquiry One thing is common to all forms of science: an ultimate goal "to know." Curiosity and inquiry are the driving forces for the development of science.

Scientists seek to understand the world and the way it operates.

There are two main pathways of scientific study: descriptive science and hypothesis-based science. Descriptive or discovery) science aims to observe, explore, and discover, while hypothesis-based science begins with a specific question or problem and a potential answer or solution that can be tested.

The boundary between these two forms of study is often blurred, because most scientific endeavors combine both approaches.

Hypothesis Testing Biologists study the living world by posing questions about it and seeking science-based responses. This approach is common to other sciences as well and is often referred to as the scientific method.

The scientific method was used even in ancient times, but it was first documented by England's Sir Francis Bacon 1561-1626) (Figure). The scientific method is not exclusively used by biologists but can be applied to almost anything as a logical problem-solving method.

The scientific method is a method of research with defined steps that include experiments and careful observation.

The steps of the scientific method will be examined in detail later, but one of the most important aspects of this method is the testing of hypotheses. A hypothesis is a suggested explanation for an event, which can be tested.

Each experiment will have one or more variables and one or more controls. A variable is any part of the experiment that can vary or change during the experiment.

There are three types of variables we will discuss: Independent variables) of interest, independent variables not of interest controlled variables), and dependent variables.

To test a hypothesis, a researcher will conduct one or more experiments designed to eliminate one or more of the hypotheses.

This is important. A hypothesis can be shown to be incorrect, or eliminated, but it can never be proven.

Observations lead to questions, questions lead to forming a hypothesis as a possible answer to those questions, and then the hypothesis is tested.

Thus, descriptive science and hypothesis-based science are in continuous dialogue.

If they do not, then we reject our hypothesis. Be aware that rejecting one hypothesis does not determine whether or not the other hypotheses can be accepted; it simply eliminates one hypothesis that is not valid Figure).

Using the scientific method, the hypotheses that are inconsistent with experimental data are rejected.

A hypothesis must be testable to ensure that it is valid. For example, a hypothesis that depends on what a bear thinks is not testable, because it can never be known what a bear thinks.

``It should also be falsifiable, meaning that it can be shown to be incorrect by experimental results.

communication from another researcher

about unpublished results with the cited author's permission.

There are many journals and the popular press that do not use a peer-review system. A large number of online open-access journals, journals with articles available without cost,

are now available many of which use rigorous peer-review systems, but some of which do not. Results of any studies published in these forums without peer review are not reliable and should not form the basis for other scientific work. In one exception, journals may allow a researcher to cite a personal

For this reason, an important aspect of a scientist's work is disseminating results and communicating with peers. Scientists can share results by presenting them at a scientific meeting or conference,

but this approach can reach only the limited few who are present. Instead, most scientists present their results in peer-reviewed articles that are published in scientific journals.

Science does not deal in proofs like mathematics. If an experiment fails to show a hypothesis is incorrect, then we find support for that explanation,

but this is not to say that down the road a better explanation will not be found, or a more carefully designed experiment will be found to falsify the hypothesis.

Scientists publish their work so other scientists can reproduce their experiments under similar or

different conditions to expand on the findings. The experimental results must be consistent with the findings of other scientists.

Look for the variables and controls in the example that follows. An experiment is conducted to test the hypothesis that phosphate limits the growth of algae in freshwater ponds. A series of artificial ponds are

filled with water and half of them are treated by adding phosphate each week, while the other half are treated by adding a salt that is known not to be used by algae. The independent variable of interest here is the phosphate or lack of phosphate), the experimental or treatment cases are the ponds with added phosphate and the control ponds are those with something inert added, such as the salt.

Science is a very specific way of learning, or knowing, about the world. The history of the past 500 years demonstrates that science is a very powerful way of knowing about the world;

it is largely responsible for the technological revolutions that have taken place during this time. There are however, areas of knowledge and human experience that the methods of science cannot be applied to.

Peer-reviewed articles are scientific papers that are reviewed, usually anonymously by a scientist's colleagues, or peers. These colleagues are qualified individuals,

often experts in the same research area, who judge whether or not the scientist's work is suitable for publication.

Scientific theory is the foundation of scientific knowledge. In addition, in many scientific disciplines less so in biology)

there are scientific laws, often expressed in mathematical formulas, which describe how elements of nature will behave under certain specific conditions.

It is important to realize that independent variables other than the brand of fertilizer could affect plant growth:

soil moisture content, amount of sunlight, temperature, In order to prevent these variables from impacting the results, they are "controlled", meaning they are not allowed to change during the experiment.

basic experiments will only have one independent variable of interest

the factor that is being changed in a deliberate manner to determine if it has an impact on the dependent variable).

The dependent variable is the one being measured. if an experiment is designed to test the effects of three different brands of plant fertilizer on plant growth,

the independent variable of interest is the brand of fertilizer and the dependent variable is plant growth.