Experimental Design Vocabulary

New Vocabulary Independent Variable Dependent Variable Constant Control Hypothesis Qualitative observation Quantitative observation Inference Question Pseudoscience Science Scientific law Scientific theory

Independent Variable (IV): (into- down/away-hang/weigh) (different-ability/worth) (in an experiment) a variable that is intentionally changed to observe its effect on the dependent variable. is the variable that is varied or manipulated by the researcher The IV is the antecedent (a thing or event that existed before or logically precedes another) Example: If a scientist conducts an experiment to test the theory that a vitamin could extend a person’s life- expectancy, then: The independent variable is the amount of vitamin that is given to the subjects within the experiment. This is controlled by the experimenting scientist.

Dependent Variable (DV): the event studied and expected to change when the independent variable is changed. is what you measure in the experiment and what is affected during the experiment. The dependent variable responds to the independent variable. It is called dependent because it "depends" on the independent variable. In a scientific experiment, you cannot have a dependent variable without an independent variable. the DV is the consequent (following as a result or effect). Example: A scientist studies the impact of a drug on cancer. The independent variables are the administration of the drug - the dosage and the timing. The dependent variable is the impact the drug has on cancer. 

Constant: (with/together-to stand) are the things that are kept the same each time one of the trials in the experiment is repeated. For example, constants could include the amount of water used, the brand of effervescent tablet used, the type of water used, and the fact that the water was not stirred. As many outside factors as possible should be kept constant in an experiment so that the researcher can be sure that any changes that occur do so because of the independent variable.

Control (to check, verify, regulate) standard of comparison, in the “natural” state a person, group, event, etc., that is used as a constant and unchanging standard of comparison in scientific experimentation. Example: testing plant fertilizer by giving it to only half the plants in a garden: the plants that receive no fertilizer are the control group, because they establish the baseline level of growth that the fertilizer-treated plants will be compared against. Without a control group, the experiment cannot determine whether the fertilizer-treated plants grow more than they would have if untreated.

Hypothesis (under-placing) a supposition or proposed explanation made on the basis of limited evidence as a starting point for further investigation. an uncertain belief Examples: If the water faucet is opened, then the amount of water flowing will increase.  If fenders are placed on a bicycle, then the user will stay dry when going through puddles. If a prisoner learns a work skill while in jail, then he is less likely to commit a crime when he is released.  If I raise the temperature of a cup of water, then the amount of sugar that can be dissolved in it will be increased. 

Qualitative Observation (how/why/nature-causing/making) Qualitative observations use your senses to observe the results. (Sight, smell, touch, taste and hear.) Quality: a distinctive attribute or characteristic possessed by someone or something. Synonyms: feature, trait, attribute, characteristic, point, aspect, facet, side, property

Quantitative Observation (measureable-condition) Quantitative observations are made with instruments such as rulers, balances, graduated cylinders, beakers, and thermometers. These results are measurable. Quantity: an amount or number of something Synonyms: abundance, amount, total, aggregate, sum, mass, weight, volume, bulk, quantum, proportion, portion, part

Inference is an attempt to explain or interpret observations or to identify the cause of what was observed. a conclusion reached on the basis of evidence and reasoning. Synonyms: deduction, conclusion, reasoning, conjecture speculation, guess, presumption, assumption, supposition, reckoning, extrapolation Example: After her guests went back for second helpings, Mary could infer that they enjoyed her meal.

Question (ask-action ) a linguistic expression used to make a request for information, or the request made using such an expression. The information requested may be provided in the form of an answer. a sentence worded or expressed so as to elicit information. Synonyms: inquiry, query, interrogate, cross examine, cross- question, quiz, catechize, interview, debrief, examine, Examples: What is the universe made of? How did life begin? What makes us human? What is consciousness? Why do we dream? When can I have a robot butler? Are there other universes?

What is science and what is it not?

Pseudoscience Pseudoscience is a claim, belief or practice which is presented as scientific, but does not adhere to a valid scientific method, lacks supporting evidence or plausibility, cannot be reliably tested, or otherwise lacks scientific status. Pseudoscience is often characterized by the use of vague, contradictory, exaggerated or unprovable claims, an over-reliance on confirmation rather than rigorous attempts at refutation, a lack of openness to evaluation by other experts, and a general absence of systematic processes to rationally develop theories. Examples: Astrology, creation science, crop circles, full moon lunacy, aromatherapy, Feng Shui, Hypnosis *lack empirical evidence

Science Science (from Latin scientia, meaning "knowledge"[1]) is a systematic enterprise that builds and organizes knowledge in the form of testable explanations and predictions about the universe.[2][3][4] In an older and closely related meaning, "science" also refers to a body of knowledge itself, of the type that can be rationally explained and reliably applied.

Scientific Law A scientific law is a statement based on repeated experimental observations that describes some aspect of the universe. A scientific law always applies under the same conditions, and implies that there is a causal relationship involving its elements. An empirical generalization; a statement of a biological principle that appears to be without exception at the time it is made, and has become consolidated by repeated successful testing; rule Examples: Newton's Law of Gravitational Force is written as g = GM/r², Newton's Second Law of Motion is written as F net = (mass) x (acceleration).

Scientific Theory A scientific theory is a well-substantiated explanation of some aspect of the natural world that is acquired through the scientific method, and repeatedly confirmed through observation and experimentation. A scientifically accepted general principle supported by a substantial body of evidence offered to provide an explanation of observed facts and as a basis for future discussion or investigation Examples: The Big Bang Theory, The Theory of Evolution, The Theory of Plate Tectonics

Empirical Evidence Empirical evidence (also empirical data, sense experience, empirical knowledge, or the a posteriori) is a source of knowledge acquired by means of observation or experimentation. The term comes from the Greek word for experience, Εμπειρία (empeiría).

What is science and what is it not? Ticket Out the Door