FTCE Middle Grades Science 5-9 (004) key terms

A cycle of observing, questioning, hypothesizing, experimenting, and analyzing data that builds reliable explanations. Steps repeat as new evidence appears rather than ending at a single conclusion.

A testable, falsifiable statement predicting a relationship between variables. It must be phrased so that evidence could show it wrong, distinguishing it from an opinion or an untestable claim.

A factor held constant across trials so it cannot explain observed changes in the dependent variable. Controlling these factors lets a fair test isolate the effect of the independent variable.

The factor a researcher deliberately changes or manipulates between conditions. It is the presumed cause, plotted on the x-axis, and its effect is measured through the dependent variable.

The factor measured or observed in response to changes in the independent variable. It is the presumed effect, plotted on the y-axis, and its data reveal whether the hypothesis is supported.

A broad, well-tested explanation supported by extensive converging evidence from many investigations. It is not a guess; theories organize laws and observations and can be revised when new evidence demands it.

A concise statement describing a consistent, repeatable pattern in nature, often expressed mathematically. Laws describe what happens under given conditions, while theories explain why it happens.

Evaluation of a study's methods, analysis, and conclusions by independent experts before publication. It filters errors and bias, though it does not guarantee that findings are correct.

A systematic error or slant that pushes results or interpretations consistently in one direction. Sources include faulty sampling, leading questions, selective reporting, and the researcher's expectations.

The number of observations or subjects included in a study. Larger samples generally reduce the influence of chance variation, making results more precise and more trustworthy.

An organized grid of rows and columns recording measurements and observations. Clear labels, units, and consistent formatting make patterns easier to spot and graphs easier to construct.

A decimal system of measurement based on units such as meter, liter, and gram, scaled by powers of ten. Conversions shift the decimal point, and prefixes like kilo- and milli- signal magnitude.

Mass per unit volume of a substance, calculated as mass divided by volume. It is an intensive property, so it does not change with sample size and helps identify materials and predict floating.

A characteristic observable or measurable without changing a substance's chemical identity, such as color, melting point, density, or conductivity. These properties help identify and separate materials.

A characteristic describing how a substance reacts or fails to react, such as flammability, reactivity with acid, or tendency to rust. Observing it produces a new substance.

A transformation altering form, size, or state without creating a new substance, such as melting, dissolving, or tearing. The original material can usually be recovered by physical means.

A transformation producing one or more new substances with different properties, often signaled by gas, precipitate, color change, or heat release. Bonds break and form, and reversal is usually difficult.

The principle that matter is neither created nor destroyed in a closed system during a chemical reaction. Total mass of reactants equals total mass of products, which explains why equations must balance.

A chemical equation with equal numbers of each type of atom on both sides, achieved by adjusting coefficients only. It reflects conservation of mass and supports quantitative predictions.

The solid, liquid, gas, and plasma forms distinguished by particle arrangement, motion, and energy. Solids hold shape, liquids flow at fixed volume, and gases expand to fill containers.

A model explaining macroscopic behavior from particles in constant random motion whose average energy depends on temperature. It accounts for diffusion, pressure, and phase changes.

The total internal energy of particles in a substance arising from their motion and interactions. It transfers as heat from warmer to cooler objects until thermal equilibrium is reached.

Heat transfer through direct contact as fast-moving particles collide with slower neighbors and pass energy along. Metals conduct well because free electrons carry energy efficiently.

Heat transfer by the movement of a fluid, where warmer, less dense material rises and cooler, denser material sinks, forming circulation currents. It drives weather, ocean currents, and mantle flow.

Three principles stating that objects resist changes in motion, acceleration depends on net force and mass, and every action has an equal and opposite reaction. Together they predict everyday motion.

An object's tendency to resist changes in its state of motion, proportional to its mass. A more massive object needs a larger net force to start, stop, or redirect it.

A push or pull that can change an object's speed, direction, or shape, measured in newtons. Forces combine as vectors, and unbalanced net force causes acceleration.

The attractive force between masses that pulls objects toward one another, weakening with distance. On Earth it accelerates falling objects near 9.8 meters per second squared, ignoring air resistance.

The amount of matter in an object, a measure of its inertia, expressed in kilograms. Mass stays constant regardless of location, unlike weight, which depends on gravitational pull.

The gravitational force acting on an object's mass, calculated as mass times gravitational acceleration and measured in newtons. It changes with location, such as on the Moon.

The upward force a fluid exerts on an immersed object, equal to the weight of fluid displaced. An object floats when this force balances its weight.

The principle that all living things consist of one or more cells, that cells arise from existing cells, and that cells carry out life's basic functions. It unifies all biological study.

A specialized structure inside a cell performing a particular job, such as mitochondria releasing energy, ribosomes building proteins, or chloroplasts capturing light. Structure matches function.

The process by which plants, algae, and some bacteria use light energy to convert carbon dioxide and water into glucose and oxygen. It stores energy and supplies food chains.

The process by which cells break down glucose, releasing usable energy stored in ATP, with carbon dioxide and water as waste products. It occurs in mitochondria when oxygen is available.

Cell division producing two genetically identical daughter cells for growth and repair. Chromosomes duplicate, align, separate, and nuclei reform, maintaining the chromosome number.

Cell division producing gametes with half the chromosome number, creating genetic variation through crossing over and independent assortment. It underlies sexual reproduction.

The transmission of traits from parents to offspring through genes carried on chromosomes. Understanding it explains inheritance patterns, variation, and inherited disorders.

The process by which individuals with heritable traits suited to their environment survive and reproduce more successfully, shifting population traits over generations. It drives adaptation and evolution.

A sequence showing how energy passes from producers to consumers and decomposers as organisms eat one another. Arrows point in the direction energy flows.

The theory that Earth's lithosphere is broken into plates that move over the asthenosphere, causing earthquakes, volcanoes, and mountain building at their boundaries.

Ground shaking caused by the sudden release of built-up stress along a fault when rock breaks or slips. Seismic waves radiate outward and are recorded by seismographs.

Vibrations traveling through Earth after a sudden release of energy. P-waves compress rock and travel fastest; S-waves move rock sideways and cannot pass through liquids.

The ongoing transformation among igneous, sedimentary, and metamorphic rock through melting, cooling, weathering, erosion, compaction, and heat and pressure. It recycles Earth's material.

The breakdown of rock in place by physical, chemical, or biological processes such as freeze-thaw, acid rain, or root wedging. Erosion then transports the loosened material.

The transport of weathered rock and soil by agents such as water, wind, ice, or gravity. It shapes landforms and, when accelerated by human activity, degrades soil.

The continuous movement of water among oceans, atmosphere, land, and living things through evaporation, condensation, precipitation, and runoff. Solar energy drives the cycle.

Atmospheric gases such as carbon dioxide and water vapor absorb and re-radiate outgoing infrared energy, warming Earth's surface. It makes life possible but intensifies with added gases.