C

Carbon Dioxide: (n.) A colorless and odorless gas, denser than air (1.977 g/L). Carbon dioxide, with the chemical formula CO₂, turns limewater cloudy. It is used in the preparation of carbonated beverages and mineral waters and is compressed in fire extinguishers.
Carbon Monoxide: (n.) A colorless, odorless, and toxic gas with the formula CO. Its density is 0.967 g/L. It forms from the combustion of carbon or carbon-containing compounds in an oxygen-deficient atmosphere or at very high temperatures, even with sufficient oxygen. It is the cause of fatal poisonings.
Carbon: (n.) Atom with an atomic number Z equal to 6. It has 6 electrons orbiting a nucleus containing 6 protons and usually 6 neutrons. Its symbol is C. Its model is a black sphere. Diamond is pure carbon used as a gemstone and, in its less precious varieties, as an abrasive due to its hardness (10 on the Mohs scale). Graphite is also pure carbon. The latter is very soft, refractory, and a good electrical conductor. It is used for preparing crucibles, electrodes, and as a moderator in nuclear reactors. There are also several amorphous varieties, including carbon black, animal charcoal, coke, and activated carbons.
Cast Shadow: (n.) Unlit area on a screen placed behind an illuminated object.
Celestial Body: (n.) Celestial object. Examples: Planet, Star, Natural Satellite like the Moon, Comet...
Change of State: (n.) Transition of matter from one physical state to another.
Chemical Energy: (n.) A form of energy contained in matter that is modified when the matter undergoes a chemical transformation. When a battery operates, it is the site of a chemical reaction, transforming chemical energy into electrical energy. During the charging of the battery, it is the site of a chemical reaction, transforming electrical energy into chemical energy.
Chemical Equation: (n.) A symbolic representation that shows the rearrangement of atoms from reactants to form products during a chemical transformation.
Chemical Reaction: (n.) A chemical transformation during which substances are consumed (the reactants) and substances are formed (the products).
Chemical Transformation: (n.) Transformation where some substances are consumed and others are formed.
Chromatogram: (n.) Result of a chromatography process.
Chromatography: (n.) Technical process that allows the separation and purification of substances using their differences in migration speeds on or through suitably chosen supports.
Circuit Breaker: (n.) Device that opens an electrical circuit in case of overcurrent. There are two types: fuses and circuit breakers.
Circuit with Branches: (n.) Electrical circuit containing at least two loops.
Closed Circuit: (n.) Circuit consisting of a continuous series of conductors in which a current flows. The switch position is closed.
Coil: (n.f.) Electrical wire (conductor and insulating sheath) wound around a cylinder. It is part of an alternator.
Color of Light: (n.) Color taken by a white object illuminated by this light.
Combustion: (n.) Chemical transformation that releases heat. Chemical energy is transformed into heat.
Compact State: (n.) A state of matter where molecules are practically touching each other.
Complete Combustion: (n.) In the case of the combustion of alkanes such as methane and butane, this combustion, which occurs in the presence of a sufficient quantity of oxygen, produces only water vapor and carbon dioxide. The flame is blue.
Compress: (v.) Decrease the volume of an "object" by increasing the pressure applied to the "object".
Compressible: (adj.) Whose volume decreases under simple pressure. That can be compressed, meaning its volume decreases when the applied pressure increases.
Condensation: (n.) Transition from the vapor state to the liquid state. Condensation can occur at any temperature but preferably happens when in contact with cold surfaces to which the vapor can transfer the heat it must release to condense (Watt's principle or cold surfaces).
Condensation: (n.f.) Collection of fine water droplets present on a cold surface.
Conventional Current Direction: (n.) Outside the generator, the current flows from the positive terminal to the negative terminal. This direction is chosen by physicists.
Convergent Lens: (n.f.) Lens that is thinner at the edge than at the center.
Convergent Light Beam: (n.) A beam of light that narrows down. The luminous energy is concentrated.
Copper: (n.) (From the Latin cyprium aes, meaning bronze of Cyprus) Atom with an atomic number Z equal to 29. It has 29 electrons orbiting a nucleus containing 29 protons and 34 or 35 neutrons. Its symbol is Cu. Copper is a reddish-brown metal. Its melting point is 1,083°C. Its boiling point is 2,595°C. Its density is 8.96 kg/L. Although not very hard, it is very malleable and ductile, and after silver, it is the best conductor of electricity. The main application of copper is its use in electrical conducting wires. It is unalterable by water or water vapor. Under the action of humid air charged with carbon dioxide, it becomes covered with a layer of hydrocarbonate or verdigris. With weak acids like vinegar, it forms toxic deposits.
Corrosion: (n.) Effect of corrosive substances. For example, the deterioration of metals due to a chemical reaction with constituents of the air (oxygen, water, and carbon dioxide).
Corrosive: (adj.) Said of substances that attack living tissues (skin) as well as materials.
Cubic Meter: (n.) The legal unit of volume (symbol m³).
Cupro-Nickel: (n.) Alloy of copper and nickel.
Current Intensity: (noun) Quantity of electricity passing through a section of the circuit per unit time (second). It is therefore a flow of "grains" of electricity. Current intensity is measured with an ammeter. The legal unit of current intensity is the ampere (Symbol A).
Current-Voltage Characteristic: (n.) Graphical representation of the variations in voltage with current for a given two-terminal component. In this graph, the current is on the x-axis (horizontal axis) and the voltage is on the y-axis (vertical axis).