[acronym] American Association for the Advancement of Science, pronounced "Triple-A ess."

• Appears in modules:

• The How and Why of Scientific Meetings

[noun] The emergence of life forms emerging from non-living chemical systems. In contrast with spontaneous generation, abiogenesis is not a process that biologists think continues in a particular environment, such as a planet or moon, once a living system has emerged.

• Appears in modules:

• Origins of Life I
• Origins of Life II

[noun] A temperature scale with its units in Kelvin. A temperature in degrees Celsius can be converted to Kelvin by adding 273.15 to its value.

• Appears in modules:

• Kinetic-Molecular Theory
• Properties of Gases

[noun] The theoretical lowest temperature possible at which all molecular motion ceases. Absolute zero, 0 K or -273.15°C, has never been reached.

• Appears in modules:

• Energy
• States of Matter
• Temperature

[verb] Take in or soak up (energy, liquids, or other substances), usually gradually, through a chemical or physical action.

• Appears in modules:

• Chemical Reactions
• Discovery and Structure of Cells
• Factors that Control Earth's Temperature
• Factors that Control Regional Climate
• Fats and Proteins
• Lipids
• Properties of Solids
• Solutions, Solubility, and Colligative Properties

[noun] In science, an abstract is a brief statement of essential information contained within a document or presentation. An abstract is not an introduction, rather it concentrates the most pertinent information to facilitate understanding of the main points of the document. Most scientific journal articles include an abstract at the beginning of the article which is uploaded to literature databases to facilitate information searches; and scientists also submit abstracts that summarize what they will present at a scientific meeting. See this Writing@CSU page for additional information.

• Appears in modules:

• Barbara McClintock
• Chemical Reactions
• Experimentation in Scientific Research
• Gene Expression
• Modeling in Scientific Research
• Peer Review in Scientific Publishing
• Scientific Controversy
• The How and Why of Scientific Meetings
• Understanding Scientific Journals and Articles
• Utilizing the Scientific Literature

[noun] The change in an object's velocity over time, measured in distance per unit time per unit time (for example meters per second per second or m/s²). Compare to velocity. Acceleration (a) is calculated by dividing the change (symbolized by Δ, the Greek letter delta) in velocity (v) by the change in time (t):

a = Δv/ Δt.

This can also be written as:

a = v₂-v₁/ t₂-t₁, where v₁ and t₁ denote the starting velocity and time and v₂ and t₂ denote the ending velocity and time.

To illustrate, imagine a car speeding up (accelerating) from a stand still (0 meters/second) to a speed of 15 meters/seconds over the course of 5 seconds. The car's total increase in velocity is 15 meters/second. During each of the 5 seconds that the car is accelerating, its velocity increases by 3 meters/second until it reaches its top speed. (After one second the car is traveling at a velocity of 3 meters/second; after 2 seconds, it's traveling at a velocity of 6 meters/second, and so on). Therefore, the car's rate of acceleration is 3 meters per second per second or 3 m/s². Using the equation above:

a = v₂-v₁/ t₂-t₁
a = 15-0 / 5-0
a = 15/5
a = 3 m/s²

• Appears in modules:

• Gravity
• The Hydrologic Cycle

[noun] In science, the term accuracy describes how well a measurement approximates the theoretically correct value of that measurement, for example, how close an arrow strikes to the center of a target. Accuracy provides a measure of the systematic error associated with a value. Compare to precision. See the module Uncertainty, Error, and Confidence.

• Appears in modules:

• Atomic Theory II
• Atomic Theory III
• Atomic Theory IV
• Comparison in Scientific Research
• Data Analysis and Interpretation
• Description in Scientific Research
• DNA III
• Exponential Equations in Science II
• Gravity
• History of Earth's Atmosphere I
• Linear Equations in Science
• Measurement
• Meselson and Stahl
• Modeling in Scientific Research
• Origins of Life II
• Properties of Minerals
• Statistics in Science
• The Nature of Scientific Knowledge
• Uncertainty, Error, and Confidence

[noun] A chemical neurotransmitter. When released onto a muscle, acetylcholine will activate sodium channels to open.

• Appears in modules:

• Membranes II

[noun] Generally, a substance that reacts with bases to form a salt, several different definitions of acids have been proposed by different scientists (listed in parentheses). 1) (Arrhenius) a compound that releases hydrogen ions (H+) in solution; 2) (Brønsted-Lowry) a compound capable of donating hydrogen ions, 3) (Lewis) a compound that can accept a pair of electrons from a base.

• Appears in modules:

• Acids and Bases
• Biological Proteins
• Cell Division I
• César Milstein
• Chemical Reactions
• Creativity in Science
• DNA I
• DNA II
• DNA III
• Early Ideas about Matter
• Energy Metabolism I
• Energy Metabolism II
• Factors that Control Earth's Temperature
• Fats and Proteins
• Gene Expression
• Lipids
• Membranes II
• Modeling in Scientific Research
• Origins of Life I
• Origins of Life II
• Properties of Minerals
• Solutions, Solubility, and Colligative Properties
• The Carbon Cycle
• The Nitrogen Cycle

[noun] Rain with a pH less than 5.

[organization] American Chemical Society

• Appears in modules:

• Comparison in Scientific Research

[noun] The energy required to initiate a chemical reaction or process, abbreviated E_a. For example, a cigarette lighter requires activation energy (provided in the form of a spark) to initiate the reaction of fuel with oxygen.

• Appears in modules:

• Chemical Bonding
• Chemical Equations
• Chemical Reactions

[noun] The opposite of passive transport, active transport involves the input of energy (usually in the form of ATP), the building of concentration gradients, and the action of a membrane pump to create high concentrations of molecules.

• Appears in modules:

• Absorption, Distribution, and Storage of Chemicals
• Membranes II

[person] Welsh astronomer, born near Launceston, Cornwall (1819-1892). He successfully predicted the existence of a then-unknown planet (Neptune) based on perturbations in Uranus' orbit. He also studied the Leonid meteor shower, successfully predicting its occurrence and proving its association with Tempel's Comet.

• Appears in modules:

• Gravity

[noun] A change that allows an organism to function better in a particular environment.

• Appears in modules:

• Adaptation
• Charles Darwin I
• Charles Darwin II
• Charles Darwin III
• David Ho
• Fabiola León-Velarde
• Future of Human Evolution

[noun] (ATP) Molecules that provide energy for important chemical reactions within the cell; the main energy currency of the cell.

• Appears in modules:

• Cellular Organelles I
• Energy Metabolism I
• Energy Metabolism II
• Membranes II
• Photosynthesis I
• The Phosphorus Cycle
• Y-Chromsome and Mitochondrial DNA Haplotypes

[noun] The interaction of a molecule with something other than itself, often related to mechanical or electrostatic forces. For example, water forms a meniscus within a glass cylinder due to adhesive forces between the water and glass.

• Appears in modules:

• Properties of Liquids
• Water

[verb] To adhere in an extremely thin layer of molecules (as of gases, solutes, or liquids) to the surfaces of solid bodies or liquids with which a substance is in contact.

[noun] The transfer of a material or of heat due to the movement of a fluid.

• Appears in modules:

• Diffusion I

[adjective] An organism or cell that requires oxygen to carry out its metabolic processes; a process that requires oxygen.

• Appears in modules:

• Cellular Organelles I
• Discovery and Structure of Cells
• Energy Metabolism I

[person] (1807-1873) A geologist and paleontologist, born and educated in Europe, but regarded as one of the founding fathers of American science. While in Switzerland and France, Agassiz studied comparative anatomy under Georges Cuvier in 1832, focusing on fossil and modern fish. In 1836, he began to study glacial landforms and became a strong proponent of the theory of glacial ice ages. In 1848, Agassiz accepted a position at Harvard University and moved to the United States, where he helped found the National Academy of Sciences, the American Association for the Advancement of Science, and served as a regent of the Smithsonian Institution.

• Appears in modules:

• The How and Why of Scientific Meetings

[noun] (15th-early 17th century) also referred to as the Age of Discovery, this was a time in history during which Europeans explored and mapped the world, establishing primary contacts with Africa, the Americas, Asia and Oceania. In particular, Portuguese and Spanish explorers made ocean voyages in search of alternative trade routes to the Indies, the source of gold, silver and spices.

• Appears in modules:

• Taxonomy I

[noun] The clumping together cells bearing antigens, microorganisms, or particles when in the presence of an antibody. When the clumping involves red blood cells, the process is called hemagglutination.

• Appears in modules:

• Blood Biology I

[person] (aka Georg Pawer/Bauer) German geologist and medical doctor, born in Glauchau, Saxony (1494-1555). Agricola wrote several influential geological manuscripts, including De Natura Fossilium (1546), De Ortu et Causis Subterraneorum (1546) and De Re Metallica (published posthumously in 1556). The later is his most influential work, being a compendium of everything then known about mining, including (but not limited to) equipment, methods of surveying for and extracting minerals, mine administration, and the occupational diseases of miners.

• Appears in modules:

• Defining Minerals

[noun] A scientist whose focus is the management of soil and the production of crops. Agronomy includes the study of farming practices: The effect a farmer’s actions have on the soil and surrounding environment.

• Appears in modules:

• The Phosphorus Cycle

[acronym] American Geophysical Union.

• Appears in modules:

• Scientific Institutions and Societies
• The How and Why of Scientific Meetings

[noun] The fraction of reflected solar radiation off of light-colored surfaces on Earth, such as clouds, snow, ice, and sandy deserts. Earth reflects about 30% of the solar radiation it receives.

• Appears in modules:

• Factors that Control Earth's Temperature
• Factors that Control Regional Climate

[noun] A medieval chemical philosophy concerned principally with the transformation of base metals into gold, and the discovery of an elixir of life.

• Appears in modules:

• Chemical Reactions

[noun] An organic compound containing a hydroxyl group. Common examples include methanol (CH₃OH) and ethanol (CH₃CH₂OH).

• Appears in modules:

• Carbon Chemistry
• Chemical Reactions
• Confidence Intervals
• Lipids
• Membranes I
• Scientists and the Scientific Community
• Solutions, Solubility, and Colligative Properties
• Temperature

[noun] (plural form of alga) Mostly aquatic plantlike organisms that range in size from one cell to large multi-celled seaweed and are photosynthetic.

• Appears in modules:

• Cellular Organelles I
• Lipids
• Photosynthesis I
• The Nitrogen Cycle
• The Phosphorus Cycle

[person] The Latinized name for the Muslim scientist Abū-Alī al-Hasan ibn al-Hasan ibn al-Haytham who was born in Basra, Mesopotamia (Iraq) (965-1039 CE). Alhazen made significant contributions in the fields of astronomy, mathematics, medicine, and most significantly, optics. His work in optics irrefutably proved that vision is a function of external light rays entering the human eye; and his rigorous and quantitative approach formed the basis of the modern experimental method in science.

• Appears in modules:

• Experimentation in Scientific Research
• Light I
• The Practice of Science
• Utilizing the Scientific Literature

[noun] Any of a class of nitrogen-containing organic compounds that come from plants and have an effect on the body. Common alkaloids include caffeine, nicotine, and codeine.

• Appears in modules:

• Cell Division II
• Percy Lavon Julian

[noun] A group of hydrocarbons with the general formula C_nH_(2n+2). Alkanes contain no carbon-carbon multiple bonds; common examples include methane and propane.

• Appears in modules:

• Carbon Chemistry

[noun] A group of hydrocarbons with the general formula C_nH_(2n). Alkenes contain at least one carbon-carbon double bond; common examples include ethylene.

• Appears in modules:

• Carbon Chemistry

[noun] A group of hydrocarbons with the general formula C_nH_(2n-2). Alkynes contain at least one carbon-carbon triple bond; common examples include ethyne also known as acetylene.

• Appears in modules:

• Carbon Chemistry

[noun] A variation of a genetic element, usually resulting in a distinct trait.

• Appears in modules:

• Future of Human Evolution
• Mendel and Inheritance
• Population Genetics
• Theories, Hypotheses, and Laws
• Y-Chromsome and Mitochondrial DNA Haplotypes

[noun] The ability of a single element to form multiple solids. For example, graphite and diamond are different solids both formed by carbon.

• Appears in modules:

• Properties of Solids

[noun] A type of particle that is ejected from radioactive nuclei. Alpha particles consist of two protons and two neutrons and thus are equivalent to helium nuclei.

• Appears in modules:

• Atomic Theory I
• Atomic Theory II
• Nuclear Chemistry

[noun] In statistical testing, an alternative hypothesis (H₁) is a statement describing the possibility that an observed result or effect is genuine. The alternative hypothesis is always compared to a null hypothesis (H₀), and H₁ is not accepted until statistical testing shows that it should be accepted in favor of H₀. For example, in an evaluation of data regarding the pain relieving properties of a new drug, the alternative hypothesis would state that the new drug has an effect on pain relief compared to a control. Accepting H₁ does not indicate that the observed result or effect is large or important, simply that it is favored in terms of probability of the outcome.

• Appears in modules:

• The Case of the Ivory-billed Woodpecker

[adjective] Pertaining to an alveolus.

• Appears in modules:

• Absorption, Distribution, and Storage of Chemicals

[noun] A small sac-like structure in the body, especially common in the lung. A lung alveolus has extremely thin walls that aid in the exchange of gases including O₂ and CO₂.

• Appears in modules:

• Absorption, Distribution, and Storage of Chemicals

[organization] A professional society established in 1848 that serves scientists in all disciplines. The mission of AAAS is to "advance science, engineering, and innovation throughout the world for the benefit of all people." AAAS hosts an annual meeting, publishes the journal Science, and has numerous programs that promote science education and the interactions between science and policy. More information about AAAS can be found on their website.

• Appears in modules:

• France Anne-Dominic Córdova
• The How and Why of Scientific Meetings
• Using Graphs and Visual Data in Science

[organization] A professional society for chemists established in 1876. The mission of ACS is "to advance the broader chemistry enterprise and its practitioners for the benefit of Earth and its people." In addition to publishing journals and holding meetings, ACS provides competitive funding for research through its Petroleum Research Fund. More information about ACS can be found on their website.

• Appears in modules:

• Mario Molina
• Ruth Benerito
• Scientific Ethics
• Scientific Institutions and Societies
• The How and Why of Scientific Meetings

[organization] A professional society established in 1919, originally as part of the National Academy of Sciences, but now an independent organization. The mission of AGU is "to promote discovery in Earth and space science for the benefit of humanity"; the primary means of achieving that mission is through hosting two annual meetings and publishing numerous journals. More information about AGU can be found on their website.

• Appears in modules:

• Scientific Institutions and Societies
• The How and Why of Scientific Meetings

[noun] Biochemical molecules that contain at least one amine group (-NH₂) and at least one carboxylic acid group (-COOH) and conform to the general formula NH₂-R-COOH, where R is an organic molecule. Amino acids are essential basic building blocks of proteins.

• Appears in modules:

• Biological Proteins
• Cell Division I
• César Milstein
• DNA I
• Energy Metabolism I
• Fats and Proteins
• Gene Expression
• Membranes II
• Origins of Life I
• Origins of Life II

[adjective] Having no specific arrangement or organization. Amorphous solids are those that have no specific arrangement of atoms and usually melt over a broad temperature range and break unpredictably, producing fragments with irregular, often curved surfaces.

• Appears in modules:

• Properties of Minerals
• Properties of Solids

[person] French mathematician born in Poleymieux, Lyon (1775-1836). Ampere researched metaphysics, physics, and chemistry, but he focused on mathematics, which he taught at the Ecole Polytechnique in Paris. His key contributions to science include his work on partial differential equations, the discovery of fluorine, and studies on the wave theory of light. His most important work was the Memoir on the Mathematical Theory of Electrodynamic Phenomena, Uniquely Deduced from Experience, in which he described a mathematical derivation for the electrodynamic force law. The Amp (a measurement of electrical current) is named in his honor.

• Appears in modules:

• Light and Electromagnetism

[adjective] Having the ability to live both on land and in water.

• Appears in modules:

• Adaptation

[adjective] (from the Greek amphi, "both," and philic, "loves," so together it means "loves both") Molecules that are both water-soluble (hydrophilic) and oil-soluble (lipophilic).

• Appears in modules:

• Lipids

[noun] Magnitude; a measure of height from the highest to lowest point on a vertical axis; a measure of the size of a wave.

• Appears in modules:

• Light I
• Wave Mathematics
• Waves and Wave Motion

[noun] The careful study of data to look for patterns.

• Appears in modules:

• Blood Biology I
• Bone Changes in Rock Climbers
• Confidence Intervals
• Creativity in Science
• Data Analysis and Interpretation
• David Ho
• Defining Minerals
• Experimentation in Scientific Research
• Future of Human Evolution
• Introduction to Inferential Statistics
• Kevin Arrigo
• Lipids
• Louis Tompkins Wright
• Mendel and Inheritance
• Meselson and Stahl
• Origins of Life II
• Peer Review in Scientific Publishing
• Percy Lavon Julian
• Properties of Minerals
• Scientific Controversy
• Scientific Ethics
• Scientists and the Scientific Community
• Sergio Avila
• Statistics in Science
• The Carbon Cycle
• The How and Why of Scientific Meetings
• The Piltdown Hoax
• The Practice of Science
• The Process of Science
• Uncertainty, Error, and Confidence
• Understanding Scientific Journals and Articles
• Unit Conversion
• Using Graphs and Visual Data in Science
• Utilizing the Scientific Literature
• Y-Chromsome and Mitochondrial DNA Haplotypes

[person] (510–428 BCE) Ionian Greek philosopher. He posited the idea of panspermia, that life on Earth had begun as seedlings that had arrived through space from other worlds.

• Appears in modules:

• Early Ideas about Matter
• Origins of Life I

[person] (610–546 BCE) Ionian Greek philosopher. He put forth an early idea about human origins in which humans had evolved gradually from fish. This echoes aspects of modern evolutionary theory. However, in ancient Greece Anaximander’s idea developed into the concept of spontaneous generation that grew into a complex hypothesis that persisted for 24 centuries.

• Appears in modules:

• Experimentation in Scientific Research
• Origins of Life I

[noun] A convergent plate boundary, where oceanic crust is being subducted beneath continental crust. Named after the Andes Mountains in South America, which are the classic example of a continent-ocean convergence.

• Appears in modules:

• Plates, Plate Boundaries, and Driving Forces

[noun] An extrusive igneous rock of intermediate composition, often gray in color. The main minerals present in andesite are plagioclase and hornblende. The word "andesite" comes from the Andes Mountains in South America, where this rock type is common. Around the world, andesitic magma erupts out of volcanoes along convergent boundaries, and its intrusive equivalent is diorite.

• Appears in modules:

• The Rock Cycle
• The Silicate Minerals

[noun] Also written as Ångstrom. A unit of length equivalent to 10^-10 meters. 1Å = 0.0000000001 m.

[noun] The momentum possessed by an object in rotation around a point, it is the analog to linear momentum. In physics, one of the fundamental conserved quantities in classical and quantum mechanics (the others are mass, energy, and linear momentum). Total angular momentum of a particle in quantum mechanics is the sum of the spin angular momentum and the orbital angular momentum. The units of Planck's constant are units of angular momentum.

• Appears in modules:

• Atomic Theory III
• Atomic Theory IV

[noun] A negatively charged ion that migrates to the anode in an electrical cell.

• Appears in modules:

• Atomic Theory II
• Chemical Bonding
• Chemical Reactions
• Properties of Minerals
• The Phosphorus Cycle
• The Silicate Minerals

[noun] A positively charged terminal in an electrical cell.

• Appears in modules:

• Atomic Theory I

[noun] A deviation from the normal or expected, sometimes expressed with respect to an average value. Anomalies are described in many kinds of data, and are features of datasets that require explanation.

• Appears in modules:

• Data Analysis and Interpretation
• Population Genetics

[acronym] A statistical test of significance for three or more subsamples. Short for “analysis of variance,” ANOVA is a method of statistical hypothesis testing that generalizes Student’s t-test to more than two groups without incorporating the additional error associated with repeatedly conducting tests of statistical significance.

• Appears in modules:

• Introduction to Inferential Statistics

[noun] Male part of a flowering plant that holds pollen.

• Appears in modules:

• Mendel and Inheritance
• Scientists and the Scientific Community

[noun] A Y-shaped protein molecule that is produced by the immune system in response to infection by an antigen. Different antigens provoke the production of different antibodies. Antibodies fight disease by attaching themselves to antigens, destroying them or surrounding them so that they cannot attack the body.

• Appears in modules:

• Biological Proteins
• César Milstein

[noun] A substance that stimulates the production of an antibody by the immune system. Antigens include toxins, bacteria, foreign blood cells, and cells of transplanted organs.

• Appears in modules:

• Blood Biology I
• César Milstein

[noun] A protein that simultaneously transports two different molecules, in opposite directions, across the membrane.

• Appears in modules:

• Membranes II

[noun] (Also known as top-level predator or alpha predator) A carnivorous species at the top of the food chain in a particular ecosystem with no natural predators other than humans. Examples include large cats (lions, jaguars, tigers, etc.), sharks, wolves, bears, anaconda snakes, and others. Removing these top predators can have ripple effects throughout an ecosystem.

• Appears in modules:

• Sergio Avila

[adjective] Related to, located in, or living in or on a body of water. Not terrestrial. Aquatic includes both freshwater and saltwater (marine) environments.

• Appears in modules:

• Carlos J. Finlay
• Modeling in Scientific Research
• The Nitrogen Cycle
• The Phosphorus Cycle
• Water

[noun] A porous and permeable body of rock or sediment through which groundwater flows.

• Appears in modules:

• The Hydrologic Cycle

[noun] (plural of archaeon) One of three domains of life on Earth (the other two being Bacteria and Eukaryota), consisting of single-celled organisms that are prokaryotes (lacking membrane-bound organelles), yet phylogenetically and biochemically are as distinct from the Bacterial domain as they are from Eukaryotes.

• Appears in modules:

• Cell Division II
• Cellular Organelles I

[person] Greek mathematician, born in Syracuse, Sicily (287-212 BCE). Little is known about Archimedes' life, but he is best known for devising the water displacement method of measuring the volume of an irregularly-shaped object (which he possibly conceived of while getting into his bathtub). He is also credited with developing the foundations of integral calculus and mathematical physics.

• Appears in modules:

• Density

[person] A Greek philosopher born in Stagira (384-322 BCE). He joined Plato's Academy in Athens (then being run by Eudoxus) at the age of 17. After attending the academy, he taught there for 20 years before founding his own school, the Lyceum. He is remembered primarily for his works on deductive logic and the use of philosophical reasoning to address questions about the natural world.

• Appears in modules:

• Charles Darwin I
• Charles Darwin III
• Early Ideas about Matter
• Energy
• Factors that Control Earth's Temperature
• Light I
• Origins of Life I
• Scientific Institutions and Societies
• Taxonomy I
• The Nature of Scientific Knowledge
• The Practice of Science

[noun] See mean.

• Appears in modules:

• Introduction to Descriptive Statistics

[person] Swedish physical chemist born in Vik (1859-1927). Arrhenius is most famous for what is now known as the Arrhenius equation, which relates the rate of chemical reactions to temperature and activation energy. Arrhenius was awarded the Royal Society's Davy medal and the Faraday medal of the Chemical Society in 1914, and the Nobel Prize for Chemistry in 1903 based on his early work on the conductivity of electrolytes in solution.

• Appears in modules:

• Acids and Bases
• Atomic Theory II
• Factors that Control Earth's Temperature

[noun] A blood vessel that conveys oxygenated blood away from the heart to other parts of the body.

• Appears in modules:

• Adaptation
• Comparison in Scientific Research
• Lipids
• Louis Tompkins Wright

[noun] The process of mating certain animals or plants to intentionally pass along desirable traits to the next generation; also called selective breeding.

• Appears in modules:

• Future of Human Evolution

[noun] The semi-molten layer of the earth which starts at ~70-200 km depth and ends at 660 km depth. The asthenosphere is part of the mantle, and is composed primarily of the rock peridotite. The asthenosphere can flow very slowly, allowing rigid pieces of the lithosphere to move around on top of it.

• Appears in modules:

• Earth Structure

[noun] The branch of biology concerned with the search for life forms native to worlds other than Earth and with the origin, distribution, and evolution of life throughout the cosmos.

• Appears in modules:

• France Anne-Dominic Córdova
• Origins of Life I

[noun] The collective mass of gases that surrounds the Earth or another planet.

• Appears in modules:

• Carlos J. Finlay
• Cellular Organelles I
• Composition of Earth's Atmosphere
• Craig Lee
• Data Analysis and Interpretation
• Description in Scientific Research
• Diffusion I
• Discovery and Structure of Cells
• Ellen Ochoa
• Energy Metabolism I
• Exponential Equations in Science II
• Factors that Control Earth's Temperature
• Factors that Control Regional Climate
• Future of Human Evolution
• History of Earth's Atmosphere I
• History of Earth's Atmosphere II
• Kevin Arrigo
• Luis E. Miramontes
• Luis Walter Alvarez
• Mario Molina
• Modeling in Scientific Research
• Origins of Life I
• Properties of Gases
• Scientific Controversy
• The Carbon Cycle
• The Hydrologic Cycle
• The Nitrogen Cycle
• The Phosphorus Cycle
• The Practice of Science
• The Rock Cycle
• Uncertainty, Error, and Confidence
• Unit Conversion
• Using Graphs and Visual Data in Science
• Water

[noun] The smallest unit of an element that retains the chemical properties of the element. Atoms can exist alone or in combinations with other atoms forming molecules.

• Appears in modules:

• Atomic Theory I
• Atomic Theory II
• Atomic Theory III
• Atomic Theory IV
• Biological Proteins
• Carbohydrates
• Carbon Chemistry
• Chemical Bonding
• Chemical Equations
• Chemical Reactions
• Composition of Earth's Atmosphere
• Creativity in Science
• Defining Minerals
• Density
• Diffusion I
• DNA I
• DNA II
• Early Ideas about Matter
• Energy
• Energy Metabolism I
• Energy Metabolism II
• Fats and Proteins
• France Anne-Dominic Córdova
• Franklin Chang Díaz
• Gene Expression
• History of Earth's Atmosphere I
• History of Earth's Atmosphere II
• Kinetic-Molecular Theory
• Lipids
• Luis E. Miramontes
• Luis Walter Alvarez
• Mario Molina
• Membranes I
• Meselson and Stahl
• Modeling in Scientific Research
• Nuclear Chemistry
• Origins of Life I
• Origins of Life II
• Percy Lavon Julian
• Photosynthesis I
• Properties of Gases
• Properties of Liquids
• Properties of Solids
• Scientific Ethics
• Scientific Notation and Order of Magnitude
• Solutions, Solubility, and Colligative Properties
• States of Matter
• Teaching Effectively with Multimedia
• The Mole and Atomic Mass
• The Nitrogen Cycle
• The Periodic Table of Elements
• The Phosphorus Cycle
• The Silicate Minerals
• Thermodynamics I
• Uncertainty, Error, and Confidence
• Using Graphs and Visual Data in Science
• Water

[noun] The average mass of an atom of an element, usually expressed in atomic mass units. The term is often used interchangeably with atomic weight.

• Appears in modules:

• Atomic Theory II
• Confidence Intervals
• Density
• Diffusion I
• History of Earth's Atmosphere II
• Meselson and Stahl
• Nuclear Chemistry
• The Mole and Atomic Mass

[noun] One atomic mass unit (amu or u) is defined as 1/12 the mass of the standard carbon-12 isotope, or 1.66 × 10^-27 kg.

[noun] The number of protons in an atomic nucleus.

• Appears in modules:

• Nuclear Chemistry
• The Periodic Table of Elements

[noun] See electron orbitals.

• Appears in modules:

• Atomic Theory IV

[noun] Compare with Bohr radius and hartree. A system of non-SI units used in quantum chemistry to simplify calculations and mathematical expressions. The definitions of atomic units include physical constants (like the speed of light, the rest mass of the electron, and other quantities that never change), so that all constants drop out of expressions when atomic units are used.

[noun] As listed on the periodic table, the atomic weight is a weighted average of the masses of stable isotopes of an element that occur in nature. Given in grams, the atomic weight is the weight of one mole of atoms of an element. Atomic weight is often used interchangeably with atomic mass.

• Appears in modules:

• Early Ideas about Matter
• Nuclear Chemistry
• The Mole and Atomic Mass
• The Periodic Table of Elements

[noun] Adenosine triphosphate. Molecules that provide energy for important chemical reactions within the cell.

• Appears in modules:

• Energy Metabolism I
• Energy Metabolism II
• Membranes II
• Photosynthesis I

[noun] The behavior of waves as they radiate out from a source. As distance from the source increases, intensity of the waves decreases. Attenuation occurs because the same amount of energy is being spread out over a larger area.

• Appears in modules:

• Earth Structure

[noun] In statistics, average commonly refers to the arithmetic mean, also called simply "mean," which is one measure of the mid-point of a dataset. See mean for more details.

• Appears in modules:

• Atomic Theory II
• Comparison in Scientific Research
• Composition of Earth's Atmosphere
• Confidence Intervals
• Craig Lee
• Data Analysis and Interpretation
• Diffusion I
• Earth Structure
• Exponential Equations in Science II
• Factors that Control Earth's Temperature
• Factors that Control Regional Climate
• History of Earth's Atmosphere I
• Introduction to Descriptive Statistics
• Introduction to Paleoanthropology
• Kinetic-Molecular Theory
• Linear Equations in Science
• Modeling in Scientific Research
• Properties of Minerals
• The Carbon Cycle
• The Hydrologic Cycle
• The Mole and Atomic Mass
• The Process of Science
• Uncertainty, Error, and Confidence
• Using Graphs and Visual Data in Science

[person] (October 21, 1877 - February 2, 1955) A Canadian-born American physician and medical researcher, considered one of the founders of immunochemistry, a branch of chemistry that deals with the immune system. Avery was part of the team, along with Maclyn McCarty and Colin MacLeod, which discovered that DNA is the genetic basis of life. Later, Avery served as president of the American Association of Immunologists, the American Association of Pathologists and Bacteriologists, and the Society of American Bacteriologists, and received numerous honors and recognitions for his medical research.

• Appears in modules:

• DNA I

[noun] The relationship between a gas’s volume (V) and amount (n, in moles), which was based on the work of the Italian scientist Amedeo Avogadro. Avogadro’s Law states that at a constant pressure and temperature, a gas’s volume is directly proportional to its amount.

[person] Italian chemist and mathematician born in Turin (1776-1856). Avogadro was schooled to be an ecclesiastical lawyer, but retained an interest in natural philosophy, and studied mathematics and physics on his own. In 1811, Avogadro made the first distinction between molecules and atoms. He further suggested Avogadro’s Law: Equal volumes of gas at the same pressure and temperature contain the same number of molecules. Avogadro's number, which defines the number of atoms in a mole, is named after him for his disambiguation of molecules.

• Appears in modules:

• Properties of Gases
• The Mole and Atomic Mass