Québec Sec 4 Applied Science and Technology (057-410) flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Density formula

Density equals mass divided by volume (ρ = m/V). It is an intensive property, so it does not change with sample size, and it explains floating or sinking in water.

Chemical change

A transformation producing one or more new substances with different properties. Evidence includes colour change, gas, precipitate, or heat release, not merely melting or dissolving.

Pure substance

Matter with fixed composition and uniform properties: either an element made of one kind of atom or a compound made of atoms in a fixed ratio.

Distillation

A separation technique based on different boiling points. Heating vaporizes the more volatile component, which is then condensed and collected separately from the mixture.

Balanced chemical equation

An equation in which coefficients make the number of atoms of each element equal on both sides, respecting the law of conservation of mass.

pH scale

A 0 to 14 scale of acidity: below 7 acidic, 7 neutral, above 7 basic. Each unit represents a tenfold change in hydrogen ion concentration.

Dilution relation

C₁V₁ = C₂V₂. Adding solvent increases volume and decreases concentration while the amount of dissolved solute stays constant.

Exothermic reaction

A reaction that releases energy, usually as heat, so the surroundings warm up. Combustion and neutralization are common examples in everyday contexts.

Cell theory

All living things are made of one or more cells, the cell is the basic unit of life, and all cells come from pre-existing cells.

Natural selection

Heritable variations that improve survival and reproduction become more frequent in a population over generations, because their bearers leave more offspring.

Ecosystem

A community of interacting organisms plus the non-living factors of their environment, such as water, soil, light, and temperature, linked by energy and matter flows.

Binomial nomenclature

The two-part scientific name of a species: capitalized genus followed by lowercase species, both italicized, for example Homo sapiens.

Homeostasis

The maintenance of stable internal conditions such as temperature, blood glucose, and water balance, achieved mainly through negative feedback loops.

Mitosis versus meiosis

Mitosis yields two identical diploid cells for growth and repair; meiosis yields four genetically varied haploid gametes for sexual reproduction.

Dominant allele

An allele whose trait appears in the phenotype even when only one copy is present; the recessive allele shows only when two copies are inherited.

Punnett square

A grid predicting offspring genotype probabilities by combining the possible gametes of two parents, for example Aa × Aa gives 3:1 dominant to recessive.

Engineering design process

An iterative cycle: define the problem, set constraints and specifications, generate ideas, prototype, test, evaluate, then improve the solution.

Orthographic projection

A multiview drawing showing front, top, and side views aligned on one sheet, with hidden edges dashed and centre lines marked.

Scale ratio

The ratio of a drawing dimension to the real dimension. At 1:50, one centimetre on the drawing represents fifty centimetres in reality.

Mechanical stress

Stress equals force divided by cross-sectional area (σ = F/A). A part fails when stress exceeds the material's yield or ultimate strength.

Mechanical advantage

The ratio of output force to input force, or load to effort. A lever, pulley system, or gear train can increase force while reducing distance or speed.

Ohm's law

Voltage equals resistance times current (U = RI). It links the three quantities in a resistive circuit and allows one to be calculated from the other two.

Series circuit

A single-path circuit in which current is identical everywhere, voltages add, resistances add, and one break stops current in the whole circuit.

Parallel circuit

A circuit with separate branches across the same voltage. Branch currents add, total resistance is lower than any branch, and one break leaves others working.

Plate tectonics

The theory that Earth's lithosphere is divided into plates that move over the asthenosphere, producing earthquakes, volcanoes, mountain chains, and ocean ridges.

Rock cycle

The continuous transformation among igneous, sedimentary, and metamorphic rocks through melting, cooling, weathering, erosion, deposition, compaction, and metamorphism.

Water cycle

The circulation of water through evaporation, transpiration, condensation, precipitation, infiltration, and runoff, driven mainly by solar energy and gravity.

Cause of seasons

Earth's 23.5-degree axial tilt changes the angle and duration of sunlight through the year. Distance from the Sun is not the cause of seasons.

Controlled variable

A factor deliberately held constant across trials so that any observed change in the dependent variable can be attributed to the independent variable.

Hypothesis

A testable, falsifiable prediction about the relationship between variables, stated before data collection and revised if evidence contradicts it.

Scientific model

A simplified representation of a phenomenon used to explain or predict. Its assumptions and limits must be stated because it omits or distorts some factors.

Reliability versus validity

Reliability means repeated trials give consistent results; validity means the experiment actually measures what it claims, which requires controlling relevant variables.