Scientific Method and Experimental Design Vocabulary

Vocabulary flashcards covering fundamental scientific method concepts, types of studies, experimental variables, sources of bias, experimental controls, and research ethics derived from the lecture transcript.

Concentration Gradient

A difference in the amount of a substance between two areas, causing particles to naturally move from an area of high concentration to an area of low concentration.

Scientific Method

A structured, repeatable plan and series of steps used by scientists to ask questions, conduct experiments, and gather trustworthy information to advance scientific knowledge.

Observational Study

A scientific study in which existing subjects or natural conditions are observed without manipulating variables or assigning treatments, used to identify trends and correlations.

Controlled Experiment

A scientific study in which researchers randomly assign subjects to different treatment groups and manipulate specific variables to determine cause-and-effect relationships.

Correlation

A mutual relationship or trend identified between two variables in an observational study that does not establish a direct cause-and-effect link.

Hypothesis

A proposed causal explanation for an observed event that must be both testable and falsifiable.

Prediction

A specific forecast of an experimental outcome that is expected to occur if a given hypothesis is correct.

Independent Variable

The specific factor or treatment that an experimenter intentionally changes or manipulates between experimental groups.

Dependent Variable

The variable being measured or recorded as a response to changes made to the independent variable.

Control Variable

Any environmental or procedural condition that is kept identical across all treatment groups to ensure a fair test.

Subject

The individual unit, living organism, or object to which an independent variable or experimental treatment is applied.

Control Group

A group of subjects in an experiment that does not receive the experimental treatment, establishing a baseline measurement for comparison.

Positive Control

An experimental setup designed to show what a known positive result looks like under controlled conditions.

Negative Control

An experimental setup where the independent variable is omitted to confirm that no unexpected outcome occurs under baseline conditions.

Bias

Any factor other than objective truth that influences or alters the design, execution, or results of a study.

Sample Bias

An unintentional error resulting from non-random sampling, leading to inaccurate conclusions about a broader population.

Confirmation Bias

The human tendency to unintentionally seek out, favor, or interpret information that aligns with pre-existing beliefs or expectations.

Placebo

An inactive or fake treatment, such as a sugar pill, given to a control group in a study to serve as a baseline comparison.

Placebo Effect

A measurable physiological or psychological change in subjects receiving a fake treatment due to their belief that they are receiving an active treatment.

Double-Blind Study

An experimental setup in which neither the test subjects nor the administering researchers know who is receiving the active treatment or the placebo.

Replicate

An individual subject or trial that receives the same experimental treatment to increase reliability and account for variation.

IRB (Institutional Review Board)

A committee established at research institutions to review, approve, and oversee experiments involving human subjects to ensure ethical standards.

IACUC (Institutional Animal Care and Use Committee)

A committee that reviews and approves scientific research proposals involving vertebrate animals to minimize pain and enforce ethical treatment.