Science

Entropy is a thermodynamic state quantity and a related statistical measure of microscopic multiplicity or uncertainty.

An enzyme is a biological catalyst that accelerates specific chemical reactions without being consumed in the overall reaction.

Epigenetics studies persistent changes in gene activity that occur without alterations to the DNA sequence, including mechanisms that maintain cellular identity and transmit regulatory states.

An equation of state relates the macroscopic properties of matter, describing how pressure, temperature, density, and other state variables depend on one another.

A family of physical principles linking universal free fall to the local equivalence of gravitation and acceleration.

Ernest Rutherford was a New Zealand-born physicist who established the nuclear model of the atom and pioneered research on radioactive decay and nuclear transformations.

A eukaryote is an organism whose cells characteristically contain a membrane-bound nucleus and specialized internal compartments.

Differential equations expressing the stationarity of an integral functional, fundamental to variational calculus, mechanics, and field theory.

Evolution is the change in heritable traits of populations over generations. It explains how all life on Earth descends from a common ancestor and has become diverse.

An exon is a segment of a gene retained in a mature RNA transcript, whether or not it encodes protein.

An experiment is a systematic investigation that manipulates conditions and measures outcomes to test explanations, estimate effects, or explore phenomena.

Extinction is the disappearance of all members of a species or other biological group, ending its existence as a living lineage.

The Faraday constant is the electric charge per mole of elementary charges, linking electrical measurements with chemical amounts in electrochemistry.

Faraday’s law relates induced electromotive force to changing magnetic flux and describes how time-varying magnetic fields generate circulating electric fields.

Feedback is a process in which a system’s output or consequences return to influence its subsequent behavior, enabling regulation, amplification, adaptation, or instability.

Fermi energy is the zero-temperature occupation boundary of a fermion system, setting a characteristic scale for its quantum behavior.

A Fermi surface is the boundary in momentum space that organizes the low-energy electronic states of a metal or other fermionic system.

Fermi–Dirac statistics describes the occupation of quantum states by identical fermions, incorporating the restriction that no two may occupy the same single-particle state.

A fermion is a particle with half-integer spin whose exchange statistics enforce the Pauli exclusion principle.

Ferromagnetism is magnetic ordering in which interacting magnetic moments develop spontaneous parallel alignment below a characteristic temperature.

Fertilizer supplies plant nutrients to support growth and replace nutrients removed from soils, with effects shaped by composition, application, and environmental conditions.

A Feynman diagram is a graph that encodes a mathematical contribution to a perturbative calculation in quantum field theory and related areas of physics.

The fine-structure constant is a dimensionless physical constant that characterizes the strength of electromagnetic interactions and governs important features of atomic spectra and quantum electrodynamics.

The first law of thermodynamics expresses energy conservation by relating changes in a system’s energy to heat, work, and energy carried by matter.

A modified nucleotide structure at the 5′ end of most eukaryotic messenger RNAs that supports RNA stability, processing, and translation.

A vector quantity describing an interaction that can change a body's momentum, produce rotation, or deform matter.

Fossil fuels are nonrenewable, carbon-rich energy sources formed from ancient organic matter, principally coal, petroleum, and natural gas.

FOXP3 is a transcription factor essential for regulatory T-cell function and immune tolerance; pathogenic variants in its gene cause IPEX syndrome.

The French Academy of Sciences is a learned society founded in 1666 that promotes scientific research, provides expert advice, and supports scientific education and international cooperation.

German chemist who developed ammonia synthesis, received the 1918 Chemistry Nobel Prize, and directed chemical-warfare research during World War I.

Fugacity is a pressure-dimensioned thermodynamic quantity that expresses chemical potential and enables equilibrium calculations for nonideal substances.

Fungi are a kingdom of absorptive, heterotrophic eukaryotes that includes yeasts, molds, and mushroom-forming organisms.

A galaxy is a gravitationally bound system of stars, gas, dust, and usually dark matter, forming a major component of cosmic structure.

A gamma ray is a high-energy photon produced by nuclear transitions, particle interactions, or energetic astrophysical processes.

The gas constant relates temperature to molar energy and appears in the ideal gas law and many thermodynamic and chemical equations.

A framework describing physical interactions through fields with local transformation freedoms that leave observable predictions unchanged.

Gauss’s law relates the electric flux through a closed surface to the net electric charge enclosed by that surface.

A gene is a unit of hereditary information whose sequence encodes a functional RNA or contributes to the production of a protein.

Gene expression is the regulated process through which genetic information produces functional RNA or protein products.

Gene flow is the transfer of genetic material between populations, influencing genetic diversity, adaptation, and evolutionary divergence.

The General Conference on Weights and Measures is the intergovernmental authority responsible for international measurement policy and the International System of Units.

General relativity describes gravity as spacetime curvature and relates that curvature to the distribution of matter and energy.

The genetic code is the set of rules by which nucleotide triplets specify amino acids or termination signals during protein synthesis.

Genetic drift is random change in allele frequencies caused by chance sampling in finite populations, often leading to loss or fixation of variants.

Genetic linkage is the tendency of DNA sequences on the same chromosome to be inherited together, forming the basis of linkage mapping.

Genetics is the study of heredity and biological variation, examining how genetic information is transmitted, expressed, and changed.

A genome is the complete genetic material of an organism or virus, encompassing genes, regulatory sequences, and other coding and noncoding regions.

Germ theory explains infectious diseases as consequences of specific biological agents interacting with susceptible hosts and their environments.

Gibbs free energy is a thermodynamic potential that determines equilibrium and the capacity for non-expansion work at constant temperature and pressure.

A phenomenological field theory describing superconductivity through a spatially varying complex order parameter, with broader applications to phase transitions and critical phenomena.

A gluon is a massless elementary particle that carries the strong interaction between quarks and also interacts with other gluons.

German mathematician and philosopher who independently developed calculus and contributed to logic, metaphysics, mechanics, and binary arithmetic.

A statistical description of an equilibrium system that exchanges energy and particles with a reservoir at fixed temperature, volume, and chemical potential.

Gravitational lensing is the deflection of light by gravity, producing changes in apparent position, shape, brightness, or image number.

A gravitational wave is a propagating disturbance in spacetime curvature that carries energy and reveals the dynamics of astronomical sources.

Gravity is the fundamental interaction that attracts objects with mass or energy. General relativity describes it as the curvature of spacetime.

A greenhouse gas absorbs and emits infrared radiation, contributing to Earth’s natural greenhouse effect and, when concentrations increase, altering the climate.

Gregor Mendel was an Augustinian friar whose pea-plant experiments established fundamental principles of inheritance and helped found modern genetics.

A hadron is a color-neutral composite particle governed by the strong interaction, including protons, neutrons, mesons, and exotic multiquark states.

Hadronization is the nonperturbative process through which quarks and gluons form color-neutral hadrons.