Science

The calculus of variations studies extrema and stationary values of functionals, typically by varying functions, curves, or fields subject to prescribed constraints.

Calibration establishes relationships between reference values and instrument indications, including their uncertainties, so that indications can be converted into measurement results.

Calorimetry measures heat exchanged during chemical reactions and physical processes, enabling determination of energy changes, heat capacities, and thermal transitions.

Cancer is a group of diseases characterized by uncontrolled growth of abnormal cells, invasion of surrounding tissues, and potential spread to distant organs.

The canonical ensemble describes equilibrium systems with fixed particle number and volume that exchange energy with a reservoir at a prescribed temperature.

Capacitance quantifies the charge stored per unit electric potential difference, governing electrical energy storage and the behavior of capacitors.

A capacitor is a passive electrical component that stores energy through the separation of electric charge, usually across an insulating dielectric.

Carbon is the chemical element with atomic number 6, whose versatile bonding underlies organic chemistry, life, and many important materials.

The carbon cycle is the movement and transformation of carbon among Earth’s atmosphere, organisms, oceans, soils, sediments, and rocks.

Swedish naturalist and physician who standardized binomial species names and developed influential systems of biological classification.

The Carnot cycle is an ideal reversible thermodynamic cycle that establishes the maximum efficiency of a heat engine operating between two thermal reservoirs.

The cell is the smallest membrane-bound unit of life. It can metabolize, grow and reproduce, and all living organisms are made of cells.

The cell cycle is the regulated sequence of growth, genome duplication, and division through which a cell produces daughter cells.

Cell division produces daughter cells through coordinated partitioning of genetic material and cellular contents, supporting reproduction, growth, and tissue renewal.

The cell membrane is a dynamic, selectively permeable boundary that regulates exchange, communication, and interactions between a cell and its surroundings.

The cell nucleus is a membrane-enclosed compartment that houses most eukaryotic DNA and organizes genetic activity.

A cell wall is a mechanically supportive layer outside the cell membrane, found in plants, fungi, most bacteria, many archaea, and numerous algae.

Cellular respiration converts energy from chemical fuels into ATP through oxidation and membrane-associated electron transport.

Cellulose is a glucose-based structural polymer that reinforces plant cell walls and supplies raw material for paper, textiles, and other products.

CERN is an intergovernmental research organization near Geneva that operates particle accelerators and supports international investigations into the fundamental constituents and interactions of matter.

Charles Darwin was an English naturalist whose theory of evolution by natural selection transformed the scientific understanding of life’s diversity and shared ancestry.

Chemical potential measures how a system’s thermodynamic energy changes with composition and determines equilibrium in particle exchange, phase coexistence, and chemical reactions.

Chemiosmosis couples the movement of ions down a membrane-spanning electrochemical gradient to ATP synthesis and other energy-requiring cellular processes.

Chemistry is the natural science that studies the composition, structure and properties of substances, how they react and change, and the energy involved.

Chemotherapy uses anticancer drugs to kill malignant cells or inhibit their growth, with treatment schedules and effects varying by drug and cancer type.

Chinese theoretical physicist who shared the 1957 Nobel Prize in Physics and co-developed Yang–Mills gauge theory.

Chien-Shiung Wu was a Chinese American experimental physicist whose work demonstrated parity violation in the weak interaction.

Chirality is the property of an object or molecular arrangement that cannot be superimposed on its mirror image, giving it a distinct handedness.

A chloroplast is a photosynthetic organelle in plants and algae that converts light energy into chemical energy and supports carbon assimilation.

Chromatin is the DNA–protein complex that packages eukaryotic chromosomes and regulates access to genetic information.

Chromatography separates mixture components through their different distributions or interactions between a stationary phase and a moving phase.

Chromosomal crossover is the reciprocal exchange of DNA between homologous chromosomes, generating new allele combinations and supporting accurate chromosome segregation during meiosis.

A chromosome is an organized DNA-containing structure that carries genetic information and enables its transmission during cell division and reproduction.

Classical mechanics describes motion, equilibrium, and mechanical interactions using Newtonian laws and analytical formulations, within limits set by quantum and relativistic effects.

Click chemistry is a modular approach to molecular construction that uses reliable, selective reactions to join building blocks efficiently.

Climate change is a persistent alteration of climate patterns, including modern warming driven primarily by human greenhouse gas emissions.

CMS is a general-purpose experiment at CERN’s Large Hadron Collider that studies fundamental particles and interactions.

Coal is a carbon-rich combustible rock formed from ancient plant material and used as a fuel and industrial raw material.

A codon is a three-nucleotide sequence that specifies an amino acid or a termination signal during protein synthesis.

The interdisciplinary study of mind and intelligence through behavioral experiments, computational models, philosophical analysis, and investigations of the brain.

Color charge is the quantum property of quarks and gluons that determines their participation in the strong interaction.

Color confinement is the absence of isolated quarks and gluons as observable particles, a defining long-distance property of quantum chromodynamics.

Combustion is an exothermic chemical process in which a fuel reacts with an oxidizer, releasing heat and often producing a flame.

Compton scattering is the interaction of a photon with an electron that changes the photon’s direction and energy through electron recoil.

Condensed matter physics studies how interacting constituents produce the collective properties of solids, liquids, and related systems.

Conservation biology studies biodiversity loss and develops scientific approaches to protecting species, populations, ecosystems, and evolutionary processes.

Conservation of mass states that a closed system’s mass remains constant in classical physics and ordinary chemistry, with relativistic qualifications arising from mass–energy equivalence.

A conservative force does work that depends only on the initial and final positions, allowing its effects to be described by potential energy.

Control theory studies how inputs and feedback can shape the behavior of dynamic systems while meeting stability, performance, and constraint requirements.

A Cooper pair is a correlated pair of fermions whose collective quantum behavior underlies conventional superconductivity and several forms of superfluidity.

The study of metal–ligand complexes, their bonding, structures, reactions, and roles in biological systems and functional materials.

A coordination polymer is an extended compound whose repeating units are connected through coordination bonds in one, two, or three dimensions.

Correlation length is the characteristic spatial scale over which fluctuations in a system remain correlated.

The cosmic microwave background is relic radiation from the early universe, whose spectrum and spatial variations reveal its thermal history, composition, and structure.

A constant term in Einstein’s gravitational equations, equivalent to uniform vacuum energy, whose positive value can drive accelerated cosmic expansion.

Cosmology studies the universe as a whole, including its origin, composition, large-scale structure, evolution, and possible future.

The coulomb is the SI unit of electric charge, equal to the charge transferred by a current of one ampere in one second.

Coulomb’s law describes the electrostatic force between point charges as proportional to their charge product and inversely proportional to their squared separation.

CRISPR is a microbial genetic defense system whose RNA-guided machinery has been adapted for genome editing, gene regulation, and molecular detection.

A critical exponent describes the power-law behavior of a physical quantity near a continuous phase transition.