[noun - biomolecules, cells] Occurs when a channel assists molecules in moving through a membrane. For example, a sodium channel creates a path through the membrane for sodium ions to flow freely.

[person - energy, physical & chemical properties, laws & theories, units of measurement] German physicist born in Danzig, Poland (1686-1736). Fahrenheit invented the alcohol thermometer in 1709, and the mercury thermometer in 1714. He also developed the temperature scale now known as Fahrenheit, which defines freezing as 32°F, boiling as 212°F, and body temperature as 98.6°F.

• Appears in modules:

• Data Analysis and Interpretation

[person - energy, physical & chemical properties, electromagnetism] British chemist and physicist born in London (1791-1867). In 1831, Faraday discovered electromagnetic induction, the principle by which electric transformers and generators function. The farad, a unit of electrical capacitance, is named in his honor.

• Appears in modules:

• Atomic Theory I
• Atomic Theory II
• Energy
• Light and Electromagnetism

[person - units of measurement, calculus, geometry, statistics, trigonometry] A French lawyer and mathematician, born in Beaumont-de-Lomagne (1602-1665 CE). Fermat had a very successful career in the criminal court, but retained a deep interest in mathematics. He made contributions toward the development of calculus and analytical geometry; and along with Blaise Pascal he laid the foundations of probability theory which led to development of statistical methods. For further information, see our module Statistics in Scientific Research.

• Appears in modules:

• Wave Mathematics

[person - atoms & subatomic particles, modern physics] (1901–1954). Italian experimental and theoretical physicist, remembered as the "architect of the nuclear age." He led research in the Manhattan Project that created the first nuclear reactor, Chicago Pile-1. For discovering transuranic elements and for work on induced radioactivity by neutron bombardment, Fermi received the Nobel Prize in Physics in 1938.

[noun - atmospheric science, weather & climate] The atmospheric circulation cell that operates within the 30-60° latitude bands. Cold, dry air sinks near 30° N and S and flows towards the poles and rises over the polar front around 60° N and S.

[person - atmospheric science, weather & climate] (1817-1891) American schoolteacher and meteorologist. Ferrel is best known for his contributions to describing and explaining circulation in what is now known as the Ferrel cell, which operates in the latitude bands between 30° and 60°. As a writer for a nautical almanac and scientist at the Coast and Geodetic Survey, Ferrel conducted extensive research on tides. He designed a machine to predict maximum and minimum tide heights and times, which was used by the survey from 1885 through the 1910s.

• Appears in modules:

• Factors that Control Regional Climate

[person - electromagnetism, modern physics, thermodynamics] American physicist, born in Queens, New York (1918-1988). Feynman is best known for his work on quantum mechanics, quantum electrodynamics, and particle theory. In 1965, he was the joint recipient of the Nobel Prize in physics (with Julian Schwinger and Shin-Ichiro Tomonaga) for his work on quantum electrodynamics. Feynman also worked on the Manhattan Project and participated on the panel that investigated the Space Shuttle Challenger disaster. In addition, he published several popular semi-autobiographical books.

[person - atoms & subatomic particles, matter, physical & chemical properties, atoms & subatomic particles, matter] German physicist and physiologist (1829-1901) born in Kassel, Germany. Building upon the work of Thomas Graham, Fick introduced the notion of diffusivity, also know as the diffusion coefficient, that describes how fast molecules diffuse.

• Appears in modules:

• Diffusion I

[adjective - genetics & inheritance, organisms] In science, filial is commonly used to designate the sequence of generations following the parental generation. For example, the first filial generation (abbreviated as F1) would be the direct offspring of a parental generation, the second filial generation (F2) would be the offspring of the first filial generation.

• Appears in modules:

• Mendel and Inheritance

[noun - atoms & subatomic particles, energy] The energy required to remove one mole of electrons from one mole of neutral, gaseous atoms, to form one mole of singly charged (positive) gaseous ions.

• Appears in modules:

• Atomic Theory II

[noun - energy, thermodynamics] One of three Laws of Thermodynamics, or laws relating to heat power. The First Law explores the conservation of energy. Specifically, this law explains that energy cannot be created or destroyed, only transformed from one form to another. It also states that the energy within a closed system is fixed – it cannot increase or decrease. The First Law is often expressed as an equation: ∆U = Q - W, or the change in internal energy (∆U) equals the heat added to the system (Q) minus the work done by the system (W). See also the Second Law of Thermodynamics and the Third Law of Thermodynamics.

• Appears in modules:

• Thermodynamics I

[person - statistics, data, research methods, scientific concepts] English statistician, geneticist, and evolutionary biologist born in London (1890-1962). He is considered the father of modern statistics. In 1919, Fisher began working at the Rothamsted Experimental Station. Six years later, he published Statistical Methods for Research Workers, drawing on his experience in creating statistically valid experiments. In 1935, Fisher published The Design of Experiments. Both works are still considered standards in the field of statistics. Fisher also contributed extensively to understanding population genetics, and was a staunch promoter of eugenics.

• Appears in modules:

• Comparison in Scientific Research
• Confidence Intervals
• The Practice of Science

[noun - evolution & adaptation, taxonomy & systematics] An idea popular among 16th and 17th century European zoologists and botanists that reflected Western religion and the story of creation as laid out in the Bible. A key feature of the argument for "fixity" was the notion that the structure of each species was based on a model, ideal form and never changed. With the publication of Darwin's and other scientists' work on evolution, the idea is no longer considered by scientists. For more information, see our module Charles Darwin I.

• Appears in modules:

• Charles Darwin I
• Scientists and the Scientific Community
• Theories, Hypotheses, and Laws

[noun - hydrology & fresh water, landforms & geologic formations, weather & climate, natural resources, weather & climate] The relatively flat land adjacent to a river channel that is underwater when the river floods. The floodplain is the site of deposition of sediments carried down the river and are often occupied by farms, due to the proximity of irrigation water, fertile soils, and flat topography.

• Appears in modules:

• The Rock Cycle

[noun - oceanography] wreckage of a ship or its cargo found floating on the ocean or washed ashore

[adjective - matter, physical & chemical properties, fluid mechanics & hydraulics, matter] Able to flow because the intermolecular forces allow the molecules to move around in relation to one another. Both liquids and gases are fluid.

• Appears in modules:

• Acids and Bases II
• Carbon Chemistry
• Density
• Diffusion I
• Discovery and Structure of Cells
• Earth Structure
• Energy Metabolism I
• Fabiola León-Velarde
• Lipids
• Membranes I
• Membranes II
• Modeling in Scientific Research
• Percy Lavon Julian
• Properties of Liquids
• Santiago Ramón y Cajal and Camillo Golgi
• Scientists and the Scientific Community
• Temperature
• The Rock Cycle
• Thermodynamics I
• Water

[noun] branch of math and physics that deals with the description and study of the flow of liquids and gases

[noun - biomolecules, matter, physical & chemical properties, rocks & minerals] The emission of light by a substance following the absorption of light or other energy by the substance. The emitted light is generally of longer wavelength, and lower energy, than that absorbed. Fluorescence occurs as a result of the relaxation of valence shell electrons after their excitation to higher shells. Fluorescence is related to the concepts of atomic emission and line spectra.

• Appears in modules:

• Atomic Theory I
• Properties of Minerals

[noun - genetics & inheritance, taxonomy & systematics] The names given to organisms and phenomena on the basis of cultural tradition.

[noun - energy, forces] An influence (a "push or pull") that changes the motion of a moving object (e.g., slows it down, speeds it up, changes its direction) or produces motion in a stationary object. The strength of a force is calculated by multiplying the mass of the object by its acceleration. In the metric (or SI) system, force is measured in newtons.

• Appears in modules:

• Adaptation
• Atomic Theory I
• Atomic Theory II
• Atomic Theory IV
• Cell Division II
• Charles Darwin I
• Chemical Bonding
• Defining Minerals
• Density
• Diffusion I
• Earth Structure
• Energy
• Experimentation in Scientific Research
• Factors that Control Earth's Temperature
• Factors that Control Regional Climate
• Gravity
• History of Earth's Atmosphere I
• Introduction to Inferential Statistics
• Kinetic-Molecular Theory
• Light and Electromagnetism
• Light I
• Measurement
• Mendel and Independent Assortment
• Meselson and Stahl
• Modeling in Scientific Research
• Nuclear Chemistry
• Origins of Plate Tectonic Theory
• Plates, Plate Boundaries, and Driving Forces
• Properties of Gases
• Properties of Liquids
• Properties of Minerals
• Properties of Solids
• Scientific Institutions and Societies
• Solutions, Solubility, and Colligative Properties
• States of Matter
• The Carbon Cycle
• The Hydrologic Cycle
• The Practice of Science
• Theories, Hypotheses, and Laws
• Thermodynamics I
• Unit Conversion
• Water

[noun - compounds] An expression of the composition of a chemical compound using symbols.

• Appears in modules:

• Atomic Theory IV
• Carbohydrates
• Carbon Chemistry
• Cell Division II
• Defining Minerals
• Early Ideas about Matter
• Gravity
• Linear Equations in Science
• Photosynthesis I
• Properties of Liquids
• Properties of Minerals
• Properties of Solids
• Temperature
• The Nitrogen Cycle
• The Practice of Science
• The Silicate Minerals
• Unit Conversion
• Wave Mathematics

[noun] The preserved impression or remains of an animal or plant whose living tissue has been replaced by minerals.

• Appears in modules:

• Animal Behavior
• Biodiversity I
• Cellular Organelles I
• Charles Darwin I
• Comparison in Scientific Research
• Defining Minerals
• Description in Scientific Research
• Discovery and Structure of Cells
• Factors that Control Regional Climate
• History of Earth's Atmosphere II
• Introduction to Paleoanthropology
• Luis Walter Alvarez
• Mario Molina
• Origins of Life I
• Origins of Plate Tectonic Theory
• Scientific Ethics
• Scientists and the Scientific Community
• Stoichiometry
• The Carbon Cycle
• The Nitrogen Cycle
• The Piltdown Hoax
• The Rock Cycle
• Theories, Hypotheses, and Laws
• Utilizing the Scientific Literature

[noun - evolution & adaptation, organisms, rock cycle] Collectively, the set of fossilized remains preserved in Earth’s crust that tell the history of Earth, including how and when rocks formed along with how organisms changed over time as evidenced by the appearance and disappearance of past organisms.

• Appears in modules:

• Theories, Hypotheses, and Laws

[person - energy, electromagnetism, energy, thermodynamics] American inventor, scientist, and politician, born in Boston (1706-1790). Franklin was a prolific scientist and humanitarian. In Philadelphia, he founded America's first subscription library, the city hospital, and the American Philosophical Society. He was also an inventor, designing a heat-efficient stove, swim fins, and bifocals. His experiments with electricity and lightening brought him global recognition. In the political scene, he was elected to the continental congress, signed the Declaration of Independence, and – one of his last acts before dying – wrote an anti-slavery treatise.

• Appears in modules:

• Membranes I

[person - cells, genetics & inheritance] English biophysicist and X-ray crystallographer born in London (1920-1958). Franklin discovered that DNA crystallizes into two forms, and, working with Maurice Wilkins, used X-ray crystallography to determine the molecular structure of one of these forms. Her work was instrumental in allowing James Watson and Francis Crick to determine the complete structure of DNA. Her results were shared with them without her knowledge, and her contributions were not acknowledged. When Watson, Crick, and Wilkins won a Nobel Prize for their work on the structure of DNA in 1962, Franklin was again overlooked because the Nobel Prize cannot be awarded posthumously.

• Appears in modules:

• Creativity in Science
• DNA II

[noun - atoms & subatomic particles, light & optics, modern physics] The rate at which a vibration occurs that constitutes a wave, either in a material or in an electromagnetic field, usually measured in hertz (Hz); a measure of how often a wave cycle is completed in a given unit of time.

• Appears in modules:

• Atomic Theory II
• Cell Division I
• César Milstein
• Charles Darwin III
• Description in Scientific Research
• History of Earth's Atmosphere I
• Kinetic-Molecular Theory
• Light and Electromagnetism
• Modeling in Scientific Research
• Scientific Controversy
• Scientific Ethics
• The Hydrologic Cycle
• The Nature of Scientific Knowledge
• The Nitrogen Cycle
• Theories, Hypotheses, and Laws
• Waves and Wave Motion

[noun - forces] the force resisting the movement of one surface over another. Friction acts at the interface of solids, fluid, and gases

• Appears in modules:

• States of Matter