MTTC Integrated Science (Secondary) (094) key terms

A cyclical process of observing, asking questions, forming testable hypotheses, designing controlled experiments, analyzing data, and revising explanations based on evidence rather than authority or intuition.

A proposed, falsifiable explanation for an observation that generates predictions testable through experiment or further observation; it is provisional and may be revised or rejected.

A factor held constant across experimental groups so that observed differences can be attributed to the manipulated variable rather than to confounding influences.

Evaluation of research by independent experts before publication, intended to catch methodological flaws, unsupported claims, and errors before findings enter the scientific literature.

A broad, well-tested explanation supported by extensive converging evidence that unifies many observations and predicts new ones; it is not a guess or tentative hunch.

The number of protons in an atom's nucleus, which uniquely identifies the element and determines its position on the periodic table.

The sum of protons and neutrons in a single atom's nucleus; atoms of the same element with different mass numbers are isotopes.

A variant of an element with the same number of protons but a different number of neutrons, giving it a different mass and often different nuclear stability.

A chemical bond formed when two atoms share one or more pairs of electrons, typically between nonmetals; sharing can be equal (nonpolar) or unequal (polar).

Electrostatic attraction between oppositely charged ions, formed when one atom transfers electrons to another, typically between a metal and a nonmetal.

A measure of how strongly an atom attracts shared electrons in a bond; differences in this value between bonded atoms determine bond polarity and molecular behavior.

A logarithmic scale expressing hydrogen ion concentration in a solution; values below 7 are acidic, 7 is neutral, and above 7 is basic.

A reaction involving proton transfer, commonly modeled as an acid donating a hydrogen ion to a base; the products are a conjugate base and conjugate acid.

The principle that matter is neither created nor destroyed in a chemical reaction, so total mass of reactants equals total mass of products in a closed system.

The amount of substance containing Avogadro's number (about 6.022 x 10^23) of representative particles; it links particle counts to measurable masses using molar mass.

A model explaining gas behavior by treating particles as tiny, constantly moving points whose collisions with container walls produce pressure, with average kinetic energy proportional to absolute temperature.

The state in which two or more objects in contact exchange no net heat because they share the same temperature, ending net energy flow between them.

Energy absorbed or released during a phase change at constant temperature, such as melting or boiling, without producing a change in the substance's temperature.

The relationship stating that net force equals mass times acceleration; for a given force, greater mass produces smaller acceleration.

A contact force opposing relative motion or the tendency toward motion between surfaces, converting mechanical energy into thermal energy.

The principle that energy can change forms and transfer between systems but the total energy of an isolated system remains constant.

The ordered range of electromagnetic radiation by wavelength and frequency, from long radio waves through microwaves, infrared, visible light, ultraviolet, X-rays, and short gamma rays.

Characteristics including wavelength, frequency, amplitude, and speed; wavelength times frequency equals wave speed, and amplitude relates to energy carried.

The bending of a wave as it passes between media of different speeds, caused by a change in wavelength while frequency stays constant.

The theory that Earth's lithosphere is divided into rigid plates that move over the asthenosphere, producing earthquakes, volcanoes, mountain belts, and ocean basins at their boundaries.

The ongoing transformation among igneous, sedimentary, and metamorphic rocks through melting, cooling, weathering, erosion, deposition, compaction, and heat and pressure.

The transport of weathered rock and soil material by agents such as water, wind, ice, and gravity, shaping landscapes and depositing sediment elsewhere.

The continuous circulation of water among oceans, atmosphere, land, and living things through evaporation, transpiration, condensation, precipitation, infiltration, and runoff.

Warming of a planet's surface as atmospheric gases absorb and re-emit outgoing infrared radiation, trapping energy that would otherwise escape to space.

The differential survival and reproduction of individuals with heritable traits better suited to their environment, causing those traits to become more common over generations.

Random change in allele frequencies across generations, especially pronounced in small populations, occurring independently of any fitness advantage.

A heritable trait or feature that improves an organism's ability to survive and reproduce in its environment, arising through natural selection over many generations.

The maintenance of relatively stable internal conditions, such as temperature and blood glucose, through feedback mechanisms that detect and correct deviations.

The process by which autotrophs use light energy to convert carbon dioxide and water into sugars, releasing oxygen and storing energy in chemical bonds.

The breakdown of organic molecules, often glucose, to release usable energy stored in ATP, consuming oxygen in aerobic forms and producing carbon dioxide and water.

Cell division producing two genetically identical daughter cells, used for growth, repair, and asexual reproduction in eukaryotes.

A two-stage reduction division producing haploid gametes with half the chromosome number, generating genetic variation through crossing over and independent assortment.

Patterns of trait transmission described by Gregor Mendel, including segregation of alleles and independent assortment of genes on different chromosomes.

The maximum population size an environment can sustain indefinitely given available resources, often represented as the plateau of a logistic growth curve.

Feeding positions in a food web, such as producers, primary consumers, and higher consumers, through which energy and matter move with losses at each transfer.