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1.2: Scientific Method – The Practice of Science - Biology


For an amusing look at how scientists think, check out The Pleasure of Finding Things Out: The Best Short Works of Richard Feynman (1999, New York, Harper Collins). Here we focus on the essentials of the scientific method originally inspired by Robert Boyle, and then look at how science is practiced today. Scientific method refers to a standardized protocol for observing, asking questions about, and investigating natural phenomena. Simply put, it says look/listen, infer a cause and test your inference. As captured by the Oxford English Dictionary, the essential inviolable commonality of all scientific practice is that it relies on “systematic observation, measurement, and experiment, and the formulation, testing and modification of hypotheses."

A. The Method

Adherence to the method is not strict, and may sometimes breach adherence to protocol! In the end, scientific method in actual practice recognizes human biases and prejudices and allows deviations from the protocol. Nevertheless, an understanding of scientific method will guides the prudent investigator to balance personal bias against the leaps of intuition that successful science requires. The practice of scientific method by most scientists would indeed be considered a success by almost any measure. Science “as a way of knowing” the world around us constantly tests, confirms, rejects and ultimately reveals new knowledge, integrating that knowledge into our worldview.

Here in the usual order are the key elements of the scientific method:

  1. Observe natural phenomena (includes reading the science of others).
  2. Infer and propose an hypothesis (explanation) based on objectivity and reason. Hypotheses are declarative sentences that sound like a fact, but aren’t! Good hypotheses are testable, easily turned into if/then (predictive) yes-or-no questions.
  3. Design an experiment to test the hypothesis: results must be measurable evidence for or against the hypothesis.
  4. Perform the experiment and then observe, measure, collect data and test for statistical validity (where applicable). Then, repeat the experiment.
  5. Consider how your data supports or does not support your hypothesis and then integrate your experimental results with earlier hypotheses and prior knowledge.

But, how do theories and laws fit into the scientific method?

A scientific theory, contrary to what many people think, is not a guess. Rather, a theory is a statement well supported by experimental evidence and widely accepted by the scientific community. One of the most enduring, tested theories is of course the theory of evolution. Among scientists, theories might be thought of as ‘fact’ in common parlance, but we recognize that they are still subject to testing and, modification, and may even be overturned. While some of Darwin’s notions have been modified over time, in this case, those modifications have only strengthened our understanding that species diversity is the result of natural selection. You can check out some of Darwin’s own work (1859, 1860; The Origin of Species] at Origin of Species. For more recent commentary on the evolutionary underpinnings of science, check out Dobzhansky T (1973, Nothing in biology makes sense except in the light of evolution. Am. Biol. Teach. 35:125-129) and Gould, S.J. (2002, The Structure of Evolutionary Theory. Boston, Harvard University Press).

A scientific Law is thought of as universal and even closer to ‘fact’ than a theory! Scientific laws are most common in math and physics. In life sciences, we recognize Mendel’s Law of Segregation and Law of Independent Assortment as much in his honor as for their universal and enduring explanation of genetic inheritance in living things. But Laws are not facts! Laws too, are always subject to experimental test.

Astrophysicists are actively testing universally accepted laws of physics. Strictly speaking, even Mendel’s Law of Independent Assortment should not be called a law. Indeed, it is not true as he stated it! Check the Mendelian Genetics section of an introductory textbook to see how chromosomal crossing over violates this law.

In describing how we do science, the Wikipedia entry states: “the goal of a scientific inquiry is to obtain knowledge in the form of testable explanations (hypotheses) that can predict the results of future experiments. This allows scientists to gain an understanding of reality, and later use that understanding to intervene in its causal mechanisms (such as to cure disease).” The better an hypothesis is at making predictions, the more useful it is, and the more likely it is to be correct. In the last analysis, think of Hypotheses as educated guesses and think of Theories and/or Laws as one or more experimentally supported hypothesis that everyone agrees should serve as guideposts to help us evaluate new observations and hypotheses.

A good hypothesis is a rational guess that explains scientific observations or experimental measurements. Therefore by definition, hypotheses are testable based on predictions based on logic. Additional observation can refine or change the original hypothesis, and/or lead to new hypothesis whose predictive value can also be tested. If you get the impression that scientific discovery is a cyclic process, that’s the point! Exploring scientific questions reveals more questions than answers!

We now recognize that a key component of the scientific method is the requirement that the work of the scientist be disseminated by publication! In this way, shared data and experimental methods can be repeated and evaluated by other scientists.

B. Origins of the Scientific Method

Long before the word scientist began to define someone who investigated natural phenomena beyond simple observation (i.e., by doing experiments), philosophers developed formal rules of deductive and inferential logic to try to understand nature, humanity’s relationship to nature, and the relationship of humans to each other. In fact, Boyle was not alone in doing experimental science. We therefore owe the logical underpinnings of science to philosophers who came up with systems of deductive and inductive logic so integral to the scientific method. The scientific method grew from those beginnings, along with increasing empirical observation and experimentation. We recognize these origins when we award the Ph.D. (Doctor of Philosophy), our highest academic degree! We are about to learn about the life of cells, their structure and function, and their classification, or grouping based on those structures and functions. Everything we know about life comes from applying the principles of scientific method.


Research and the Scientific Method

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Nutritional scientists discover the health effects of food and its nutrients by first making an observation. Once observations are made, they come up with a hypothesis, test their hypothesis, and then interpret the results. After this, they gather additional evidence from multiple sources and finally come up with a conclusion. This organized process of inquiry used in science is called the scientific method .

Figure 1.2 Scientific Method Steps

Scientific Method steps

In 1811, French chemist Bernard Courtois was isolating saltpeter for producing gunpowder to be used by Napoleon’s army. To carry out this isolation, he burned some seaweed and in the process, observed an intense violet vapor that crystallized when he exposed it to a cold surface. He sent the violet crystals to an expert on gases, Joseph Gay-Lussac, who identified the crystal as a new element. It was named iodine, the Greek word for violet. The following scientific record is some of what took place in order to conclude that iodine is a nutrient .

Observation. Eating seaweed is a cure for goiter , a gross enlargement of the thyroid gland in the neck.

Hypothesis. In 1813, Swiss physician Jean-Francois Coindet hypothesized that the seaweed contained iodine, and that iodine could be used instead of seaweed to treat his patients [1] .

Experimental test. Coindet administered iodine tincture orally to his patients with goiter.

Interpret results. Coindet’s iodine treatment was successful.

Hypothesis. French chemist Chatin proposed that the low iodine content in food and water in certain areas far away from the ocean was the primary cause of goiter, and renounced the theory that goiter was the result of poor hygiene.

Experimental test. In the late 1860s the program, “The stamping-out of goiter,” started with people in several villages in France being given iodine tablets.

Results. The program was effective and 80 percent of goitrous children were cured.

Hypothesis. In 1918, Swiss doctor Bayard proposed iodizing salt as a good way to treat areas endemic with goiter.

Experimental test. Iodized salt was transported by mules to a small village at the base of the Matterhorn where more than 75 percent of school children were goitrous. It was given to families to use for six months.

Results. The iodized salt was beneficial in treating goiter in this remote population.

Experimental test. Physician David Marine conducted the first experiment of treating goiter with iodized salt in America in Akron, Ohio. [2]

Results. This study was conducted on over four-thousand school children, and found that iodized salt prevented goiter.

Conclusions. Seven other studies similar to Marine’s were conducted in Italy and Switzerland, which also demonstrated the effectiveness of iodized salt in treating goiter. In 1924, US public health officials initiated the program of iodizing salt and started eliminating the scourge of goiter. Today, more than 70% of American households use iodized salt and many other countries have followed the same public health strategy to reduce the health consequences of iodine deficiency.

Career Connection

What are some of the ways in which you think like a scientist, and use the scientific method in your everyday life? Any decision-making process uses some aspect of the scientific method. Think about some of the major decisions you have made in your life and the research you conducted that supported your decision. For example, what brand of computer do you own? Where is your money invested? What college do you attend?


1.2: Scientific Method – The Practice of Science - Biology

The scientific method offers a standardized way for psychologists to test hypotheses, build on theories, and gain knowledge about the mind.

Learning Objectives

Defend each step of the scientific method as necessary to psychological research

Key Takeaways

Key Points

  • The scientific method was first outlined by Sir Francis Bacon (1561-1626) to provide logical, rational problem solving across many scientific fields.
  • The basic steps of the scientific method are: 1) make an observation that describes a problem, 2) create a hypothesis, 3) test the hypothesis, and 4) draw conclusions and refine the hypothesis.
  • The major precepts of the scientific method employed by all scientific disciplines are verifiability, predictability, falsifiability, and fairness.
  • The application of the scientific theory to psychology took the discipline from a form of philosophy to a form of science.
  • Critical thinking is a key component of the scientific method. Without it, you cannot use logic to come to conclusions.

Key Terms

  • social science: Sciences concerned with the social behavior of individuals and groups (e.g., sociology, anthropology, or psychology) and that are often considered more subjective due to the focus of study.
  • scientific method: A method of discovering knowledge about the natural world based on making falsifiable predictions (hypotheses), testing them empirically, and developing peer-reviewed theories that best explain the known data.
  • natural science: Sciences concerned with predicting and describing natural phenomena (e.g., biology, physics, or chemistry), using systematic data collection and performing controlled experiments.

All scientific disciplines are united by their use of the scientific method. The scientific method offers an objective methodology for scientific experimentation that results in unbiased interpretations of the world and refines knowledge. The scientific method was first outlined by Sir Francis Bacon (1561–1626) and allows for logical, rational problem solving across many scientific fields. Across all scientific disciplines, the major precepts of the scientific method are verifiability, predictability, falsifiability, and fairness.

The Scientific Method: The scientific method is a process for gathering data and processing information. It provides well-defined steps to standardize how scientific knowledge is gathered through a logical, rational problem-solving method. This diagram shows the steps of the scientific method, which are listed below.

The Basic Principles of the Scientific Method

Two key concepts in the scientific approach are theory and hypothesis. A theory is used to make predictions about future observations. A hypothesis is a testable prediction that is arrived at logically from a theory.

Several types of studies exist within the scientific method— experiments, descriptive studies, case studies, surveys, and non-descriptive studies. In an experiment a researcher manipulates certain variables and measures their effect on other variables in a controlled environment. Descriptive studies describe the nature of the relationship between the intended variables, without looking at cause or effect. A case study covers one specific example in which something unusual has occurred. This is often done in extreme or rare cases, usually with a single subject. Surveys are used with large groups of people who answer questions about specific subjects. Non-descriptive studies use correlational methods to predict the relationship between two (or more ) intended variables.

Verifiability means that an experiment must be replicable by another researcher. To achieve verifiability, researchers must make sure to document their methods and clearly explain how their experiment is structured and why it produces certain results.

Predictability in a scientific theory implies that the theory should enable us to make predictions about future events. The precision of these predictions is a measure of the strength of the theory.

Falsifiability refers to whether a hypothesis can disproved. For a hypothesis to be falsifiable, it must be logically possible to make an observation or do a physical experiment that would show that there is no support for the hypothesis. Even when a hypothesis cannot be shown to be false, that does not necessarily mean it is not valid. Future testing may disprove the hypothesis. This does not mean that a hypothesis has to be shown to be false, just that it can be tested.

To determine whether a hypothesis is supported or not supported, psychological researchers must conduct hypothesis testing using statistics. Hypothesis testing is a type of statistics that determines the probability of a hypothesis being true or false. If hypothesis testing reveals that results were “statistically significant,” this means that there was support for the hypothesis and that the researchers can be reasonably confident that their result was not due to random chance. If the results are not statistically significant, this means that the researchers’ hypothesis was not supported.

Fairness implies that all data must be considered when evaluating a hypothesis. A researcher cannot pick and choose what data to keep and what to discard or focus specifically on data that support or do not support a particular hypothesis. All data must be accounted for, even if they invalidate the hypothesis.

The Basic Steps of the Scientific Method

The basic steps in the scientific method are:

  • Observe a natural phenomenon and define a question about it
  • Make a hypothesis, or potential solution to the question
  • Test the hypothesis
  • If the hypothesis is true, find more evidence or find counter-evidence
  • If the hypothesis is false, create a new hypothesis or try again
  • Draw conclusions and repeat–the scientific method is never-ending, and no result is ever considered perfect

In order to ask an important question that may improve our understanding of the world, a researcher must first observe natural phenomena. By making observations, a researcher can define a useful question. After finding a question to answer, the researcher can then make a prediction (a hypothesis) about what he or she thinks the answer will be. This prediction is usually a statement about the relationship between two or more variables. After making a hypothesis, the researcher will then design an experiment to test his or her hypothesis and evaluate the data gathered. These data will either support or refute the hypothesis. Based on the conclusions drawn from the data, the researcher will then find more evidence to support the hypothesis, look for counter-evidence to further strengthen the hypothesis, revise the hypothesis and create a new experiment, or continue to incorporate the information gathered to answer the research question.

Example of the Scientific Method

To better understand the process of the scientific method, take a look at the following example:

  • Observation: My toaster doesn’t work.
  • Question: Is something wrong with my electrical outlet?
  • Hypothesis: If something is wrong with the outlet, my coffeemaker also won’t work when plugged into it.
  • Experiment: I plug my coffeemaker into the outlet.
  • Result: My coffeemaker works!
  • Conclusion: My electrical outlet works, but my toaster still won’t toast my bread.
  • Refine the hypothesis: My toaster is broken.

From this point, the process would be repeated with a refined hypothesis.

Why the Scientific Method Is Important for Psychology

The use of the scientific method is one of the main features that separates modern psychology from earlier philosophical inquiries about the mind. Compared to chemistry, physics, and other “natural sciences,” psychology has long been considered one of the “social sciences” because of the subjective nature of the things it seeks to study. Many of the concepts that psychologists are interested in—such as aspects of the human mind, behavior, and emotions—are subjective and cannot be directly measured. Psychologists often rely instead on behavioral observations and self-reported data, which are considered by some to be illegitimate or lacking in methodological rigor. Applying the scientific method to psychology, therefore, helps to standardize the approach to understanding its very different types of information.

The scientific method allows psychological data to be replicated and confirmed in many instances, under different circumstances, and by a variety of researchers. Through replication of experiments, new generations of psychologists can reduce errors and broaden the applicability of theories. It also allows theories to be tested and validated instead of simply being conjectures that could never be verified or falsified. All of this allows psychologists to gain a stronger understanding of how the human mind works.


The Broader Purposes of Scientific Research in Psychology

People have always been curious about the natural world, including themselves and their behavior. (In fact, this is probably why you are studying psychology in the first place.) Science grew out of this natural curiosity and has become the best way to achieve detailed and accurate knowledge. Keep in mind that most of the phenomena and theories that fill psychology textbooks are the products of scientific research. In a typical introductory psychology textbook, for example, one can learn about specific cortical areas for language and perception, principles of classical and operant conditioning, biases in reasoning and judgment, and people’s surprising tendency to obey authority. And scientific research continues because what we know right now only scratches the surface of what we can know.

Scientific research is often classified as being either basic or applied. Basic research in psychology is conducted primarily for the sake of achieving a more detailed and accurate understanding of human behavior, without necessarily trying to address any particular practical problem. The research of Mehl and his colleagues falls into this category. Applied research is conducted primarily to address some practical problem. Research on the effects of cell phone use on driving, for example, was prompted by safety concerns and has led to the enactment of laws to limit this practice. Although the distinction between basic and applied research is convenient, it is not always clear-cut. For example, basic research on sex differences in talkativeness could eventually have an effect on how marriage therapy is practiced, and applied research on the effect of cell phone use on driving could produce new insights into basic processes of perception, attention, and action.

Key Takeaways

  • Research in psychology can be described by a simple cyclical model. A research question based on the research literature leads to an empirical study, the results of which are published and become part of the research literature.
  • Scientific research in psychology is conducted mainly by people with doctoral degrees in psychology and related fields, most of whom are college and university faculty members. They do so for professional and for personal reasons, as well as to contribute to scientific knowledge about human behavior.
  • Basic research is conducted to learn about human behavior for its own sake, and applied research is conducted to solve some practical problem. Both are valuable, and the distinction between the two is not always clear-cut.

Exercises

  1. Practice: Find a description of an empirical study in a professional journal or in one of the scientific psychology blogs. Then write a brief description of the research in terms of the cyclical model presented here. One or two sentences for each part of the cycle should suffice.
  2. Practice: Based on your own experience or on things you have already learned about psychology, list three basic research questions and three applied research questions of interest to you.

1.2 The Scientific Methods

By the end of this section, you will be able to do the following:

  • Explain how the methods of science are used to make scientific discoveries
  • Define a scientific model and describe examples of physical and mathematical models used in physics
  • Compare and contrast hypothesis, theory, and law

Teacher Support

Teacher Support

The learning objectives in this section will help your students master the following standards:

  • (2) Scientific processes. The student uses a systematic approach to answer scientific laboratory and field investigative questions. The student is expected to:
    • (A) know the definition of science and understand that it has limitations, as specified in subsection (b)(2) of this section
    • (B) know that scientific hypotheses are tentative and testable statements that must be capable of being supported or not supported by observational evidence. Hypotheses of durable explanatory power which have been tested over a wide variety of conditions are incorporated into theories
    • (C) know that scientific theories are based on natural and physical phenomena and are capable of being tested by multiple independent researchers. Unlike hypotheses, scientific theories are well-established and highly-reliable explanations, but may be subject to change as new areas of science and new technologies are developed
    • (D) distinguish between scientific hypotheses and scientific theories.

    Section Key Terms

    experiment hypothesis model observation principle
    scientific law scientific methods theory universal

    Teacher Support

    Teacher Support

    [OL] Pre-assessment for this section could involve students sharing or writing down an anecdote about when they used the methods of science. Then, students could label their thought processes in their anecdote with the appropriate scientific methods. The class could also discuss their definitions of theory and law, both outside and within the context of science.

    [OL] It should be noted and possibly mentioned that a scientist, as mentioned in this section, does not necessarily mean a trained scientist. It could be anyone using methods of science.

    Scientific Methods

    Scientists often plan and carry out investigations to answer questions about the universe around us. Such laws are intrinsic to the universe, meaning that humans did not create them and cannot change them. We can only discover and understand them. Their discovery is a very human endeavor, with all the elements of mystery, imagination, struggle, triumph, and disappointment inherent in any creative effort. The cornerstone of discovering natural laws is observation. Science must describe the universe as it is, not as we imagine or wish it to be.

    We all are curious to some extent. We look around, make generalizations, and try to understand what we see. For example, we look up and wonder whether one type of cloud signals an oncoming storm. As we become serious about exploring nature, we become more organized and formal in collecting and analyzing data. We attempt greater precision, perform controlled experiments (if we can), and write down ideas about how data may be organized. We then formulate models, theories, and laws based on the data we have collected, and communicate those results with others. This, in a nutshell, describes the scientific method that scientists employ to decide scientific issues on the basis of evidence from observation and experiment.

    An investigation often begins with a scientist making an observation . The scientist observes a pattern or trend within the natural world. Observation may generate questions that the scientist wishes to answer. Next, the scientist may perform some research about the topic and devise a hypothesis . A hypothesis is a testable statement that describes how something in the natural world works. In essence, a hypothesis is an educated guess that explains something about an observation.

    Teacher Support

    Teacher Support

    [OL] An educated guess is used throughout this section in describing a hypothesis to combat the tendency to think of a theory as an educated guess.

    Scientists may test the hypothesis by performing an experiment . During an experiment, the scientist collects data that will help them learn about the phenomenon they are studying. Then the scientists analyze the results of the experiment (that is, the data), often using statistical, mathematical, and/or graphical methods. From the data analysis, they draw conclusions. They may conclude that their experiment either supports or rejects their hypothesis. If the hypothesis is supported, the scientist usually goes on to test another hypothesis related to the first. If their hypothesis is rejected, they will often then test a new and different hypothesis in their effort to learn more about whatever they are studying.

    Scientific processes can be applied to many situations. Let’s say that you try to turn on your car, but it will not start. You have just made an observation! You ask yourself, "Why won’t my car start?" You can now use scientific processes to answer this question. First, you generate a hypothesis such as, "The car won’t start because it has no gasoline in the gas tank." To test this hypothesis, you put gasoline in the car and try to start it again. If the car starts, then your hypothesis is supported by the experiment. If the car does not start, then your hypothesis is rejected. You will then need to think up a new hypothesis to test such as, "My car won’t start because the fuel pump is broken." Hopefully, your investigations lead you to discover why the car won’t start and enable you to fix it.

    Modeling

    A model is a representation of something that is often too difficult (or impossible) to study directly. Models can take the form of physical models, equations, computer programs, or simulations—computer graphics/animations. Models are tools that are especially useful in modern physics because they let us visualize phenomena that we normally cannot observe with our senses, such as very small objects or objects that move at high speeds. For example, we can understand the structure of an atom using models, despite the fact that no one has ever seen an atom with their own eyes. Models are always approximate, so they are simpler to consider than the real situation the more complete a model is, the more complicated it must be. Models put the intangible or the extremely complex into human terms that we can visualize, discuss, and hypothesize about.

    Scientific models are constructed based on the results of previous experiments. Even still, models often only describe a phenomenon partially or in a few limited situations. Some phenomena are so complex that they may be impossible to model them in their entirety, even using computers. An example is the electron cloud model of the atom in which electrons are moving around the atom’s center in distinct clouds (Figure 1.12), that represent the likelihood of finding an electron in different places. This model helps us to visualize the structure of an atom. However, it does not show us exactly where an electron will be within its cloud at any one particular time.

    As mentioned previously, physicists use a variety of models including equations, physical models, computer simulations, etc. For example, three-dimensional models are often commonly used in chemistry and physics to model molecules. Properties other than appearance or location are usually modelled using mathematics, where functions are used to show how these properties relate to one another. Processes such as the formation of a star or the planets, can also be modelled using computer simulations. Once a simulation is correctly programmed based on actual experimental data, the simulation can allow us to view processes that happened in the past or happen too quickly or slowly for us to observe directly. In addition, scientists can also run virtual experiments using computer-based models. In a model of planet formation, for example, the scientist could alter the amount or type of rocks present in space and see how it affects planet formation.

    Scientists use models and experimental results to construct explanations of observations or design solutions to problems. For example, one way to make a car more fuel efficient is to reduce the friction or drag caused by air flowing around the moving car. This can be done by designing the body shape of the car to be more aerodynamic, such as by using rounded corners instead of sharp ones. Engineers can then construct physical models of the car body, place them in a wind tunnel, and examine the flow of air around the model. This can also be done mathematically in a computer simulation. The air flow pattern can be analyzed for regions smooth air flow and for eddies that indicate drag. The model of the car body may have to be altered slightly to produce the smoothest pattern of air flow (i.e., the least drag). The pattern with the least drag may be the solution to increasing fuel efficiency of the car. This solution might then be incorporated into the car design.

    Snap Lab

    Using Models and the Scientific Processes

    Be sure to secure loose items before opening the window or door.

    In this activity, you will learn about scientific models by making a model of how air flows through your classroom or a room in your house.

    • One room with at least one window or door that can be opened
    • Piece of single-ply tissue paper
      1. Work with a group of four, as directed by your teacher. Close all of the windows and doors in the room you are working in. Your teacher may assign you a specific window or door to study.
      2. Before opening any windows or doors, draw a to-scale diagram of your room. First, measure the length and width of your room using the tape measure. Then, transform the measurement using a scale that could fit on your paper, such as 5 centimeters = 1 meter.
      3. Your teacher will assign you a specific window or door to study air flow. On your diagram, add arrows showing your hypothesis (before opening any windows or doors) of how air will flow through the room when your assigned window or door is opened. Use pencil so that you can easily make changes to your diagram.
      4. On your diagram, mark four locations where you would like to test air flow in your room. To test for airflow, hold a strip of single ply tissue paper between the thumb and index finger. Note the direction that the paper moves when exposed to the airflow. Then, for each location, predict which way the paper will move if your air flow diagram is correct.
      5. Now, each member of your group will stand in one of the four selected areas. Each member will test the airflow Agree upon an approximate height at which everyone will hold their papers.
      6. When you teacher tells you to, open your assigned window and/or door. Each person should note the direction that their paper points immediately after the window or door was opened. Record your results on your diagram.
      7. Did the airflow test data support or refute the hypothetical model of air flow shown in your diagram? Why or why not? Correct your model based on your experimental evidence.
      8. With your group, discuss how accurate your model is. What limitations did it have? Write down the limitations that your group agreed upon.

    Grasp Check

    1. Yes, you could use your model to predict air flow through a new window. The earlier experiment of air flow would help you model the system more accurately.
    2. Yes, you could use your model to predict air flow through a new window. The earlier experiment of air flow is not useful for modeling the new system.
    3. No, you cannot model a system to predict the air flow through a new window. The earlier experiment of air flow would help you model the system more accurately.
    4. No, you cannot model a system to predict the air flow through a new window. The earlier experiment of air flow is not useful for modeling the new system.

    Teacher Support

    Teacher Support

    This Snap Lab! has students construct a model of how air flows in their classroom. Each group of four students will create a model of air flow in their classroom using a scale drawing of the room. Then, the groups will test the validity of their model by placing weathervanes that they have constructed around the room and opening a window or door. By observing the weather vanes, students will see how air actually flows through the room from a specific window or door. Students will then correct their model based on their experimental evidence. The following material list is given per group:

    • One room with at least one window or door that can be opened (An optimal configuration would be one window or door per group.)
    • Several pieces of construction paper (at least four per group)
    • Strips of single ply tissue paper
    • One tape measure (long enough to measure the dimensions of the room)
    • Straws
    • Scissors
    • tape
    1. Group size can vary depending on the number of windows/doors available and the number of students in the class.
    2. The room dimensions could be provided by the teacher. Also, students may need a brief introduction in how to make a drawing to scale.
    3. This is another opportunity to discuss controlled experiments in terms of why the students should hold the strips of tissue paper at the same height and in the same way. One student could also serve as a control and stand far away from the window/door or in another area that will not receive air flow from the window/door.
    4. You will probably need to coordinate this when multiple windows or doors are used. Only one window or door should be opened at a time for best results. Between openings, allow a short period (5 minutes) when all windows and doors are closed, if possible.

    Answers to the Grasp Check will vary, but the air flow in the new window or door should be based on what the students observed in their experiment.

    Scientific Laws and Theories

    A scientific law is a description of a pattern in nature that is true in all circumstances that have been studied. That is, physical laws are meant to be universal , meaning that they apply throughout the known universe. Laws are often also concise, whereas theories are more complicated. A law can be expressed in the form of a single sentence or mathematical equation. For example, Newton’s second law of motion , which relates the motion of an object to the force applied (F), the mass of the object (m), and the object’s acceleration (a), is simply stated using the equation

    Scientific ideas and explanations that are true in many, but not all situations in the universe are usually called principles . An example is Pascal’s principle , which explains properties of liquids, but not solids or gases. However, the distinction between laws and principles is sometimes not carefully made in science.

    A theory is an explanation for patterns in nature that is supported by much scientific evidence and verified multiple times by multiple researchers. While many people confuse theories with educated guesses or hypotheses, theories have withstood more rigorous testing and verification than hypotheses.

    Teacher Support

    Teacher Support

    [OL] Explain to students that in informal, everyday English the word theory can be used to describe an idea that is possibly true but that has not been proven to be true. This use of the word theory often leads people to think that scientific theories are nothing more than educated guesses. This is not just a misconception among students, but among the general public as well.

    As a closing idea about scientific processes, we want to point out that scientific laws and theories, even those that have been supported by experiments for centuries, can still be changed by new discoveries. This is especially true when new technologies emerge that allow us to observe things that were formerly unobservable. Imagine how viewing previously invisible objects with a microscope or viewing Earth for the first time from space may have instantly changed our scientific theories and laws! What discoveries still await us in the future? The constant retesting and perfecting of our scientific laws and theories allows our knowledge of nature to progress. For this reason, many scientists are reluctant to say that their studies prove anything. By saying support instead of prove, it keeps the door open for future discoveries, even if they won’t occur for centuries or even millennia.

    Teacher Support

    Teacher Support

    [OL] With regard to scientists avoiding using the word prove, the general public knows that science has proven certain things such as that the heart pumps blood and the Earth is round. However, scientists should shy away from using prove because it is impossible to test every single instance and every set of conditions in a system to absolutely prove anything. Using support or similar terminology leaves the door open for further discovery.

    Check Your Understanding

    1. Models are simpler to analyze.
    2. Models give more accurate results.
    3. Models provide more reliable predictions.
    4. Models do not require any computer calculations.
    1. They are the same.
    2. A hypothesis has been thoroughly tested and found to be true.
    3. A hypothesis is a tentative assumption based on what is already known.
    4. A hypothesis is a broad explanation firmly supported by evidence.
    1. A scientific model is a representation of something that can be easily studied directly. It is useful for studying things that can be easily analyzed by humans.
    2. A scientific model is a representation of something that is often too difficult to study directly. It is useful for studying a complex system or systems that humans cannot observe directly.
    3. A scientific model is a representation of scientific equipment. It is useful for studying working principles of scientific equipment.
    4. A scientific model is a representation of a laboratory where experiments are performed. It is useful for studying requirements needed inside the laboratory.
    1. The hypothesis must be validated by scientific experiments.
    2. The hypothesis must not include any physical quantity.
    3. The hypothesis must be a short and concise statement.
    4. The hypothesis must apply to all the situations in the universe.
    1. A scientific theory is an explanation of natural phenomena that is supported by evidence.
    2. A scientific theory is an explanation of natural phenomena without the support of evidence.
    3. A scientific theory is an educated guess about the natural phenomena occurring in nature.
    4. A scientific theory is an uneducated guess about natural phenomena occurring in nature.
    1. A hypothesis is an explanation of the natural world with experimental support, while a scientific theory is an educated guess about a natural phenomenon.
    2. A hypothesis is an educated guess about natural phenomenon, while a scientific theory is an explanation of natural world with experimental support.
    3. A hypothesis is experimental evidence of a natural phenomenon, while a scientific theory is an explanation of the natural world with experimental support.
    4. A hypothesis is an explanation of the natural world with experimental support, while a scientific theory is experimental evidence of a natural phenomenon.

    Teacher Support

    Teacher Support

    Use the Check Your Understanding questions to assess students’ achievement of the section’s learning objectives. If students are struggling with a specific objective, the Check Your Understanding will help identify which objective and direct students to the relevant content.

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      • Book title: Physics
      • Publication date: Mar 26, 2020
      • Location: Houston, Texas
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      Step 2: Formulate a hypothesis

      After deciding to learn more about an observation or a set of observations, scientists generally begin an investigation by forming a hypothesis, a tentative explanation for the observation(s). The hypothesis may not be correct, but it puts the scientist&rsquos understanding of the system being studied into a form that can be tested. For example, the observation that we experience alternating periods of light and darkness corresponding to observed movements of the sun, moon, clouds, and shadows is consistent with either of two hypotheses:

      1. Earth rotates on its axis every 24 hours, alternately exposing one side to the sun, or
      2. the sun revolves around Earth every 24 hours.

      Suitable experiments can be designed to choose between these two alternatives. For the disappearance of the dinosaurs, the hypothesis was that the impact of a large extraterrestrial object caused their extinction. Unfortunately (or perhaps, fortunately), this hypothesis does not lend itself to direct testing by any obvious experiment, but scientists can collect additional data that either support or refute it.


      Who Conducts Scientific Research in Psychology?

      Scientific research in psychology is generally conducted by people with doctoral degrees (usually the doctor of philosophy [PhD] ) and master’s degrees in psychology and related fields, often supported by research assistants with bachelor’s degrees or other relevant training. Some of them work for government agencies (e.g., the National Institute of Mental Health), for nonprofit organizations (e.g., the American Cancer Society), or in the private sector (e.g., in product development). However, the majority of them are college and university faculty, who often collaborate with their graduate and undergraduate students. Although some researchers are trained and licensed as clinicians—especially those who conduct research in clinical psychology—the majority are not. Instead, they have expertise in one or more of the many other subfields of psychology: behavioral neuroscience, cognitive psychology, developmental psychology, personality psychology, social psychology, and so on. Doctoral-level researchers might be employed to conduct research full-time or, like many college and university faculty members, to conduct research in addition to teaching classes and serving their institution and community in other ways.

      Of course, people also conduct research in psychology because they enjoy the intellectual and technical challenges involved and the satisfaction of contributing to scientific knowledge of human behavior. You might find that you enjoy the process too. If so, your college or university might offer opportunities to get involved in ongoing research as either a research assistant or a participant. Of course, you might find that you do not enjoy the process of conducting scientific research in psychology. But at least you will have a better understanding of where scientific knowledge in psychology comes from, an appreciation of its strengths and limitations, and an awareness of how it can be applied to solve practical problems in psychology and everyday life.

      Scientific Psychology Blogs

      A fun and easy way to follow current scientific research in psychology is to read any of the many excellent blogs devoted to summarizing and commenting on new findings. Among them are the following:

      • Child-Psych, http://www.child-psych.org
      • PsyBlog, http://www.spring.org.uk
      • Research Digest, http://bps-research-digest.blogspot.com
      • Social Psychology Eye, http://socialpsychologyeye.wordpress.com
      • We’re Only Human, http://www.psychologicalscience.org/onlyhuman

      You can also browse to http://www.researchblogging.org, select psychology as your topic, and read entries from a wide variety of blogs.


      Evidence-Based Approach to Nutrition

      It took more than one hundred years from iodine’s discovery as an effective treatment for goiter until public health programs recognized it as such. Although a lengthy process, the scientific method is a productive way to define essential nutrients and determine their ability to promote health and prevent disease. The scientific method is part of the overall evidence-based approach to designing nutritional guidelines [3] . An evidence-based approach to nutrition includes [4] :

      • Defining the problem or uncertainty (e.g., the incidence of goiter is lower in people who consume seaweed)
      • Formulating it as a question (e.g., Does eating seaweed decrease the risk of goiter?)
      • Setting criteria for quality evidence
      • Evaluating the body of evidence
      • Summarizing the body of evidence and making decisions
      • Specifying the strength of the supporting evidence required to make decisions
      • Disseminating the findings

      The Food and Nutrition Board of the Institute of Medicine, a nonprofit, non-governmental organization, constructs its nutrient recommendations (i.e., Dietary Reference Intakes, or DRI) using an evidence-based approach to nutrition. The entire procedure for setting the DRI is documented and made available to the public. The same approach is used by the USDA and HHS, which are departments of the US federal government. The USDA and HHS websites are great tools for discovering ways to optimize health however, it is important to gather nutrition information from multiple resources, as there are often differences in opinion among various scientists and public health organizations. Full text versions of the DRI publications are available in pdf format at https://www.nap.edu/, along with many other free publications.

      1. Zimmerman, M.B. Research on Iodine Deficiency and Goiter in the 19th and Early 20th Centuries. Journal of Nutrition. 2008 138(11), 2060–63. http://jn.nutrition.org/content/138/11/2060.full Accessed September 17, 2017 &crarr
      2. Carpenter, K.J. David Marine and the Problem of Goiter. Journal of Nutrition. 2005 135(4), 675–80. http://jn.nutrition.org/content/135/4/675.full?sid=d06fdd35-566f -42a2-a3fd- efbe0736b7ba Accessed September 17, 2017. &crarr
      3. Myers E. Systems for Evaluating Nutrition Research for Nutrition Care Guidelines: Do They Apply to Population Dietary Guidelines? J Am Diet Assoc. 2003 12(2), 34–41. http://jandonline.org/article/S0002-8223(03)01378-6/abstract. Accessed September 17, 2017. &crarr
      4. Briss PA, Zara S, et al. Developing an Evidence-Based Guide to Community Preventive Services—Methods. Am J Prev Med. 2000 18(1S), 35–43. https://www.ncbi.nlm.nih.gov/pubmed/10806978. Accessed September 17, 2017. &crarr

      1.2 Scientific Investigation

      Scientific method is a body of technique of acquiring knowledge about the nature and its phenomena.

      Basics Steps of Scientific Investigation

      1. Identifying problem
      2. Making hypothesis
      3. Plannig the investigation
      4. Identifying and Controlling Variable
      5. Conducting the experiment
      6. Collecting and recording data
      7. Analysing and interpreting data
      8. Making conclusion
      9. Preparing the report

      The 2 main scientific skills

      The 6 Science Process Skill (OCCMIP)

      1. Observation
      2. Communication
      3. Classification
      4. Measurement
      5. Inference
      6. Prediction

      Examples of Manipulative Skill

      1. Handling apparatus and material correctly.
      2. Handling specimen correctly
      3. Clean apparatus correctly
      4. Storing apparatus and reagents correctly

      Hypothesis

      Hypothesis is a suggested explanation for a specific phenomenon.

      Inference

      Inference is the act or process of deriving a conclusion based on what one already knows.


      Evidence-Based Approach to Nutrition

      It took more than one hundred years from iodine’s discovery as an effective treatment for goiter until public health programs recognized it as such. Although a lengthy process, the scientific method is a productive way to define essential nutrients and determine their ability to promote health and prevent disease. The scientific method is part of the overall evidence-based approach to designing nutritional guidelines [4] . An evidence-based approach to nutrition includes [5] :

      • Defining the problem or uncertainty (e.g., the incidence of goiter is lower in people who consume seaweed)
      • Formulating it as a question (e.g., Does eating seaweed decrease the risk of goiter?)
      • Setting criteria for quality evidence
      • Evaluating the body of evidence
      • Summarizing the body of evidence and making decisions
      • Specifying the strength of the supporting evidence required to make decisions
      • Disseminating the findings

      The Food and Nutrition Board of the Institute of Medicine, a nonprofit, non-governmental organization, constructs its nutrient recommendations (i.e., Dietary Reference Intakes, or DRI) using an evidence-based approach to nutrition. The entire procedure for setting the DRI is documented and made available to the public. The same approach is used by Health Canada of the Canadian federal government, which has great tools for discovering ways to optimize health however, it is important to gather nutrition information from multiple resources, as there are often differences in opinion among various scientists and public health organizations. Full text versions of the DRI publications are available in pdf format at https://www.nap.edu/, along with many other free publications.

      1. Zimmerman, M.B. Research on Iodine Deficiency and Goiter in the 19th and Early 20th Centuries. Journal of Nutrition. 2008 138(11), 2060–63. http://jn.nutrition.org/content/138/11/2060.full Accessed September 17, 2017 &crarr
      2. Carpenter, K.J. David Marine and the Problem of Goiter. Journal of Nutrition. 2005 135(4), 675–80. http://jn.nutrition.org/content/135/4/675.full?sid=d06fdd35-566f -42a2-a3fd- efbe0736b7ba Accessed September 17, 2017. &crarr
      3. Leung AM, Pearce EN. Iodine nutrition in North America. Hot Thyroidology 2009. 5, 1-12. &crarr
      4. Myers E. Systems for Evaluating Nutrition Research for Nutrition Care Guidelines: Do They Apply to Population Dietary Guidelines? J Am Diet Assoc. 2003 12(2), 34–41. http://jandonline.org/article/S0002-8223(03)01378-6/abstract. Accessed September 17, 2017. &crarr
      5. Briss PA, Zara S, et al. Developing an Evidence-Based Guide to Community Preventive Services—Methods. Am J Prev Med. 2000 18(1S), 35–43. https://www.ncbi.nlm.nih.gov/pubmed/10806978. Accessed September 17, 2017. &crarr


      Watch the video: Science u0026 the Scientific Method older version (January 2022).