Hiroshima Entrance Science key terms

A measure of how fast a function's output changes as its input changes, equal to the slope of the tangent line at a point. Written as f'(x) or dy/dx.

A quantity that accumulates a function's values over an interval, interpreted as the area under its graph. The definite integral is computed as the limit of summing thin rectangles.

The value a function's output approaches as its input approaches a specified point, whether or not the function is defined there. Limits underpin both derivatives and integrals.

A quantity with both magnitude and direction, such as displacement or force, represented by components or an arrow. Vectors add by components, unlike ordinary scalars.

The net force on an object equals its mass times its acceleration (F = ma). It links causes of motion (forces) to the resulting change in velocity.

The energy an object possesses due to its motion, equal to one-half its mass times the square of its speed (½mv²). It is a scalar measured in joules.

The principle that total energy in an isolated system stays constant, though it may convert between forms such as kinetic, potential, and thermal energy.

The principle that the total momentum of an isolated system remains constant when no external net force acts, making it central to collision and explosion problems.

For a conductor at constant temperature, the current through it is proportional to the voltage across it (V = IR), where R is the resistance in ohms.

The rate at which electric charge flows past a point in a circuit, measured in amperes. One ampere equals one coulomb of charge per second.

The amount of substance containing 6.02 × 10²³ elementary entities, such as atoms or molecules. It converts between particle counts and measurable masses via molar mass.

The number of elementary entities in one mole, approximately 6.02 × 10²³ per mole. It bridges the microscopic world of particles and the macroscopic world of grams.

The mass of one mole of a substance, expressed in grams per mole. It is numerically equal to the relative formula mass and links moles to weighable quantities.

A logarithmic scale from 0 to 14 expressing hydrogen ion concentration, where pH = −log₁₀[H⁺]. Values below 7 are acidic and above 7 are basic.

An acid donates protons (H⁺) while a base accepts them, according to the Brønsted–Lowry model. Their reaction produces a salt and often water.

The reaction between an acid and a base that produces a salt and water, typically releasing heat. It brings the pH of a mixture toward neutral.

A paired process in which one species loses electrons (oxidation) while another gains them (reduction). Changes in oxidation number reveal which species is oxidized.

A reversible reaction's state in which forward and reverse rates are equal, so concentrations stay constant. Le Chatelier's principle predicts how changes shift this balance.

A thin phospholipid bilayer surrounding a cell that controls which substances enter and leave. Embedded proteins enable selective transport and signaling.

A protein catalyst that speeds up biochemical reactions by lowering activation energy. Each enzyme has an active site whose shape determines its substrate specificity.

Diffusion is the net movement of particles from high to low concentration; osmosis is the diffusion of water across a selectively permeable membrane toward higher solute concentration.

The set of reactions in which cells break down glucose to release energy stored as ATP, using oxygen in aerobic pathways and producing carbon dioxide and water.

The process by which plants, algae, and some bacteria use light energy to convert carbon dioxide and water into glucose and oxygen inside chloroplasts.

DNA is a double-stranded molecule storing genetic information in base sequences; a gene is a segment of DNA that encodes a protein or functional RNA.

A type of cell division producing four genetically varied gametes with half the chromosome number of the parent cell, creating variation through crossing over and independent assortment.

The theory that Earth's rigid outer shell is divided into plates that move over the mantle, causing earthquakes, volcanoes, and mountain building at their boundaries.

Vibrations generated by earthquakes or explosions that travel through Earth. Primary (P) waves are longitudinal and fastest; secondary (S) waves are transverse and cannot pass through liquids.

The warming of a planet's surface as atmospheric gases absorb and re-emit outgoing infrared radiation. Carbon dioxide, water vapor, and methane are major contributors.

The movement of carbon among the atmosphere, oceans, soil, and living organisms through processes such as photosynthesis, respiration, and combustion of fossil fuels.

The apparent deflection of moving air or water caused by Earth's rotation, to the right in the Northern Hemisphere and to the left in the Southern Hemisphere.

In an experiment, the group that does not receive the treatment being tested, providing a baseline against which the treated group's results are compared.

The independent variable is the factor deliberately changed by the experimenter; the dependent variable is the measured outcome that may respond to those changes.

Correlation means two variables change together, while causation means one actually produces the other. A correlation alone never proves a causal relationship.

Reliability is the consistency of repeated measurements; validity is the extent to which a method measures what it claims to measure. A test can be reliable yet invalid.

The digits in a measurement that carry meaningful information about its precision. Rules for counting them govern how results of calculations are rounded and reported.

The range within which a measured value is expected to lie, arising from instrument limits and random or systematic errors. It is often stated as a plus-or-minus value.