Chapter 2: Principles of Science and Systems

Science

is a process for producing knowledge methodically and logically.

Accuracy

correctness of measurements.

Reproducibility

repeatability of results

Replication

repeating studies or tests.

Deductive Reasoning

logical reasoning from general to specific.

Inductive Reasoning

reasoning from many specific observations to produce a general rule.

Hypothesis

a testable explanation.

Scientific Theory

a description or explanation that has been supported by a large number of tests and is considered by experts to be reliable.

Probability

is a measure of how likely something is to occur.

Natural Experiment

involves observation of events that have already happened.

Manipulative Expirement

some conditions are deliberately altered and all other variables are held constant.

Controlled Study

comparing a treatment group to a control group which has not received the treatment.

Blind Expirement

researcher does not know which group has been treated until after the data has been analyzed.

Double-blind Experiment

neither the subject nor the researcher knows who is in the treatment group.

Variables

in studies there’s one dependent and one or more independent. the dependent is affected by independent. in graph, the dependent is on vertical (Y) axis and the independent is on the horizontal (X) axis.

Models

are simple representations of phenomena. They allow scientists to study complex systems and predict the effect of conditions they are too difficult to create snd control.

Systems

are networks of interdependent components and processes, with materials and energy flowing from one component of the system to another.

State Variables

stores resources such as matter or energy or have the pathways through which these resources move from one state variable to another.

System Characteristics - Open

exchanges matter and energy with surroundings.

System Characteristics - Closed

self contained, exchanges no matter or energy with the outside.

Throughput

the energy and matter that flow into through, and out of a system.

Positive Feedback Loop

self perpetuating process, as an increase in a state variable leads to further increases in it.

Negative Feedback Loop

suppresses change within a system, helps to maintain stability in systems.

Equilibrium

dynamic state in which system is stable over time (homeostasis)

Disturbance

periodic destructive events such as fire or flood that destabilize or change the system.

Resilience

ability of system to recover from disturbance.

State Shift

a severe disturbance in which the system does not return to normal but instead results in significant changes in some of its state variables.

Emergent Properties

are characteristics of a whole, functioning system that are quantitatively or qualitatively greater than the sum of the system’s parts.

Scientific Consensus

(general agreement among informed scholars) stems from a community of scientists who collaborate in a cumulative, self-correcting process.

Paradigm Shifts

(great changes in explanatory frameworks) occur when a majority of scientists agree that an old explanation no longer works very well.