Visionlearning Glossary

Formed from the cooling and crystallization of a magma. Igneous rocks can be extrusive, meaning that they cooled on or very near the earth’s surface, or intrusive, meaning that they cooled below the earth’s surface.

Used in the following modules: Minerals III, Research Methods: Description, The Rock Cycle

In science, an independent variable is a condition or parameter that is consciously manipulated in some way in the course of scientific research with the goal of observing the outcome of this manipulation on a second variable, referred to as a dependent variable. For more information, see: Research Methods: Experimentation

Used in the following modules: Research Methods: Experimentation

Deficient in active properties; especially: lacking a usual or anticipated chemical or biological action.

Used in the following modules: Chemical Reactions, Research Methods: The Practice of Science, The Nitrogen Cycle

A property of matter that is independent of the amount of material present. Common intensive properties include boiling point, color, density, melting point, and solubility.

Used in the following modules: Density

Any of those parts of geologic time from Precambrian onward when a similar or lesser portion of the earth was covered by glaciers than at present.

Used in the following modules: The Carbon Cycle

A scientific body created to evaluate the risk of human-caused climate change. The panel was established in 1988 by two organizations of the United Nations, the World Meteorological Organization (WMO) and the United Nations Environment Programme (UNEP).

Pertaining to or located between the small spaces and gaps between tissues in an organism.

An atom or molecule that has acquired an electrical charge by either gaining or losing electrons. A cation is an ion that has lost electrons and acquired a positive charge. An anion is an ion that has gained electrons and acquired a negative charge.

Used in the following modules: Absorption, Distribution and Storage of Chemicals, Acids and Bases, Atomic Theory II, Cells, Chemical Bonding, Chemical Reactions, Earth's Atmosphere, Matter: States of Matter, Minerals III, The Carbon Cycle, The Nitrogen Cycle, Water

A chemical bond characterized by electrostatic attraction between ions of opposite charge. The formation of an ionic bond involves a complete transfer of electrons between atoms, and can be predicted when one bonding atom has a much higher electronegativity than the other. Compare to covalent bond, hydrogen bond.

Used in the following modules: Chemical Bonding

A chemical compound held together by ionic bonds, that is, electrostatic attraction between positive and negative ions. Ionic compounds generally form ordered structures in which each cation is surrounded by several anions and vice versa. Thus ionic compounds commonly form complex lattices rather than true molecules.

Used in the following modules: Chemical Bonding, Water

Molecules with identical molecular formulas but differing in the sequence of bonding or arrangement in space of their atoms, i.e. their structural formulas.

Used in the following modules: Organic Chemistry

Atoms of the same element with different numbers of neutrons in their atomic nucleus. Isotopes have the same chemical properties and atomic number but different atomic masses. Isotopes can differ greatly in nuclear stability.

Used in the following modules: Atomic Theory II, Data: Analysis and Interpretation, Data: Uncertainty, Error, and Confidence, DNA I, Matter, Nuclear Chemistry

One step in an iterative process. Iteration refers to a single component of a process in which multiple, repeating steps are used to determine a solution.

Used in the following modules: Data: Uncertainty, Error, and Confidence

Repetitive in a cyclical fashion. An iterative process or method in science is one in which a sequence of steps is repeated in order to solve a problem, and each repetition of the steps brings one closer and closer to the solution. For more information, see: Data: Uncertainty, Error, and Confidence

Used in the following modules: Research Methods: Description, Research Methods: Modeling, Scientific Communication: Utilizing the Scientific Literature