Scientific Method Word Definitions: Use the definitions to answer questions on the back of this page. You can also use this page to study for quizzes and tests on scientific method.
The Scientific Method: The process that scientists use to make new evidence-based discoveries.
Asking A Question: The first step in the scientific method.
Hypothesis: A possible answer to a scientific question based on observation and inference that can be tested.
Inference: A reasonable assumption based on observation. Inferences about Nature are often wrong and thus scientific method is our most powerful tool for understanding Nature.
Observation: Basic information we receive through our senses that can be measured.
Research: Exploring information about a topic from various sources.
Design An Experiment: Finding a carefully considered way to test one’s hypothesis.
Controlled: To keep all variables but one from affecting the outcome of a scientific experiment.
Vary: to change
Variables: Things that can affect the outcome of the experiment. All variables must be controlled except the manipulated variable.
ManipulatedVariable: The one variable that you are testing and is allowed to change the outcome of a scientific experiment.
Data: Measurements gathered during a scientific experiment or investigation.
Analyze: To make sense of your data. Scientists often use mathematics to analyze data.
ConclusionAboutAHypothesis: Conclusions confirm or invalidate your hypothesis.
Experimental (Group): Science experiments often involve comparisons between a control and a experimental group. The experimental group receives the manipulated variable as in the case of testing a new drug.
Controlled (Group): The Controlled group is compared against the experimental group and receives no manipulated variable. The controlled group is considered “the norm”.
Placebo: Placebos are “fake” drugs or “fake” manipulated variables given to the controlled group.
PlaceboEffect: When a patient or test subject in the control group receives a placebo but shows an experimental effect because they believe they nay have received the manipulatedvariable (the test drug in most cases). The placebo effect is associated with lowered stress hormones in the body which can damage cells and exacerbate of cause disease.
BlindTest: When the subjects in both the control and experimental group do not know which group they are in (control or experimental).
DoubleBlindTest: When both those who administer (the doctors or nurses) the manipulated variable (test drug) and those who receive (the controlled and experimental group subjects) it don’t know if they are getting the test substance or the placebo.
Bias: Opinion on the outcome of an experiment. Opinions are subjective: what you believe whether based on fact or not. The Scientific Method is designed to rigorously seek only objective information (agreed upon by all, or consensual) about Nature.
ScientificTheory: A science based theory of how some aspect of nature or the physical world works based on rigorous testing, substantiated evidence, and peer review. Our scientific theories remain the best rational explanations of Nature and all future experiments must support the theory. A Scientific Law is a rule of Nature that remains unbroken.
Operational Definition: the standard by which a manipulated variable is judged. For example in an experiment to determine if fertilizers help plants to grow, the operational definition might be that the plants that receive fertilizer will grow higher
Responding Variable: The actual data collected in relation to the operational definition.
Subjective: Personal information, opinions and beliefs whether they are based on reality or not.
Objective: Factual information that is reality based.
Ignorance: When someone is uneducated about correct objective information and/or believes, or chooses to believe otherwise (willful ignorance) often for emotional subjective reasons.
1. Explain why saying “I like strawberry ice cream” is subjective and “The Earth revolves around the Sun” is objective. And explain why commercials are biased.
2. If you design an experiment to compare the gas mileage of cars (gas mileage is a measure of how many miles a car can go on a gallon of gas) what might be your operational definition? What might be your responding variable?
3. Explain why data is not information, but it can lead to being informed.
4. The purpose of doing blind and double blind studies with experimental medicines is to defeat the placebo effect in the control group patients. Explain why double blind studies are better at defeating the placebo effect than blind studies.
5. When scientists analyze data they are usually doing so by using mathematics. Explain why it is reasonable to expect to do or learn at least a little bit of math in a science class.
6. Explain why anecdotal evidence is not scientific evidence. Look at the paper: Pedro and the “Holy” chips if you need help.
7. In the 1990’s a scientist added vitamin A to rice to combat a form of blindness that was afflicting many children in Asia. Design a controlled experiment to test if vitamin A added to rice can help to combat blindness in children.
8. What is the difference between ignorance and willful ignorance?
9. Explain the difference between variables that must be controlled and the manipulated variable by explaining how we control all variables expect the manipulated variable in the paper towel test. Give an example of at least one variable that we controlled.
10. Explain why people who do not have control of their emotions, (emotions come from an older and more primitive part of our brain) are not likely to understand or accept scientific evidence that does not fit their own subjective view of the world.