[adjective - electromagnetism, light & optics] Wavelengths between 1 and 380 nanometers (nm) on the electromagnetic spectrum, falling between X-rays (10^-2 nm to 1 nm) and visible light (380 nm to 780 nm). Ultraviolet, or UV, radiation causes sunburn and certain skin cancers.

• Appears in modules:

• Atomic Theory IV
• Composition of Earth's Atmosphere
• Energy
• History of Earth's Atmosphere II
• Kevin Arrigo
• Light and Electromagnetism
• Mario Molina
• Meselson and Stahl
• Origins of Life I

[noun - data] The quantitative estimation of error, which indicates the precision of a measurement or value. All measurements include some amount of uncertainty generated through a combination of systematic and random error. See our module Uncertainty, Error, and Confidence.

• Appears in modules:

• Atomic Theory III
• Atomic Theory IV
• Confidence Intervals
• Data Analysis and Interpretation
• Experimentation in Scientific Research
• Introduction to Descriptive Statistics
• Introduction to Inferential Statistics
• Measurement
• Modeling in Scientific Research
• Statistics in Science
• The Mole and Atomic Mass
• The Process of Science
• The Scientific Method
• Uncertainty, Error, and Confidence
• Using Graphs and Visual Data in Science

[noun] The fundamental geological principle that the processes that are operating now to shape the world around us have been operating throughout the geologic past as well. This principle was first proposed by James Hutton in the mid-1700s, and implied that the Earth had to be billions of years old to create all of the rocks and structures we see today. Importantly, uniformitarianism does not require that all changes happen at the same rate; some processes are slow, like the deposition of sediment in deltas, others are fast, like volcanic eruptions. This principle is often paraphrased as "The present is the key to the past."

• Appears in modules:

• The Rock Cycle
• Theories, Hypotheses, and Laws

[noun - units of measurement] An accepted quantity used as a standard of measurement. For example, the meter, liter, and gram.

• Appears in modules:

• Atomic Theory I
• Carbohydrates
• Cell Division II
• Composition of Earth's Atmosphere
• Density
• Description in Scientific Research
• Diffusion I
• Energy
• Exponential Equations in Science II
• Gravity
• Kinetic-Molecular Theory
• Linear Equations in Science
• Measurement
• Nuclear Chemistry
• Santiago Ramón y Cajal and Camillo Golgi
• Scientific Notation and Order of Magnitude
• Temperature
• The Metric System
• The Mole and Atomic Mass
• Theories, Hypotheses, and Laws
• Unit Conversion
• Using Graphs and Visual Data in Science
• Wave Mathematics
• Waves and Wave Motion

[noun - cosmology] The cosmos and everything that exists in it.

• Appears in modules:

• Atomic Theory III
• Charles Darwin I
• Chemical Equations
• Composition of Earth's Atmosphere
• Description in Scientific Research
• Diffusion I
• Early Ideas about Matter
• Energy
• Factors that Control Regional Climate
• France Anne-Dominic Córdova
• Gravity
• History of Earth's Atmosphere I
• History of Earth's Atmosphere II
• Light and Electromagnetism
• Light I
• Luis Walter Alvarez
• Mario Molina
• Peer Review in Scientific Publishing
• States of Matter
• The Carbon Cycle
• The How and Why of Scientific Meetings
• The Nature of Scientific Knowledge
• The Practice of Science
• The Process of Science

[noun - evolution & adaptation, organisms] A gland on the back at the base of the tail in most birds that secretes an oily fluid used by the bird in preening and waterproofing its feathers.

• Appears in modules:

• Adaptation