MTTC Integrated Science (Secondary) (094) cheat sheet

Scientific method is iterative, not linear: observation → hypothesis → prediction → experiment → analysis → revision; hypotheses must be testable and falsifiable.

Independent variable is manipulated by the experimenter; dependent variable is measured; controlled variables are held constant to isolate cause and effect.

Control group receives no treatment (or a placebo) and establishes the baseline against which the experimental group is compared.

Reliability = consistency of repeated measurements; validity = the measurement actually reflects the intended quantity. Precise measurements can still be inaccurate.

Accuracy vs precision: accuracy is closeness to true value; precision is closeness of repeated values to each other; report as % error = |measured − accepted| / accepted × 100%.

SI base units: meter (length), kilogram (mass), second (time), ampere (current), kelvin (temperature), mole (amount), candela (luminous intensity).

Metric prefixes: kilo (10³), centi (10⁻²), milli (10⁻³), micro (10⁻⁶), nano (10⁻⁹); convert by moving the decimal the exponent difference.

Significant figures: nonzero digits count; captive zeros count; leading zeros do not; trailing zeros count only with a decimal point; multiplication/division keep least sig figs, addition/subtraction keep least decimal places.

Scientific theories are well-tested explanatory frameworks; laws describe regularities. Peer review, replication, and open data are core safeguards of scientific claims.

Classification of matter: pure substances (elements, compounds) vs mixtures (homogeneous, heterogeneous); physical changes alter form, chemical changes alter composition.

Atomic structure: protons (atomic number Z) define the element; neutrons (mass number A − Z) define isotopes; electrons occupy orbitals and determine reactivity.

Periodic trends: atomic radius decreases across a period and increases down a group; ionization energy and electronegativity increase across a period and decrease down a group.

Bonding: ionic (metal + nonmetal, electron transfer), covalent (nonmetals, electron sharing), metallic (delocalized electrons); polarity arises from electronegativity differences.

Balancing equations conserves atoms; stoichiometry uses mole ratios from balanced coefficients; molar mass converts grams ↔ moles; limiting reactant determines theoretical yield.

Reaction types: synthesis, decomposition, single replacement, double replacement, combustion, acid–base neutralization; pH = −log[H⁺].

Newton's laws: inertia (ΣF = 0 → constant velocity), F = ma, action–reaction pairs act on different objects; weight = mg.

Energy and work: W = Fd cosθ; KE = ½mv²; PE = mgh; conservation of energy; power = work/time. Ohm's law V = IR and P = IV for circuits.

Waves: v = fλ; frequency set by source, speed by medium; reflection, refraction, diffraction, interference; electromagnetic spectrum ordered by wavelength/frequency.

Cell theory: all living things are made of cells, cells are the basic unit of life, and cells arise from preexisting cells.

Prokaryotes lack membrane-bound organelles and a nucleus; eukaryotes have a nucleus and organelles (mitochondria = ATP, chloroplasts = photosynthesis, ribosomes = protein synthesis).

Photosynthesis (6CO₂ + 6H₂O + light → C₆H₁₂O₆ + 6O₂) and cellular respiration (reverse) are complementary energy transformations.

DNA structure: double helix, antiparallel strands, A–T and G–C base pairing; replication is semiconservative; transcription makes mRNA, translation makes protein at ribosomes.

Mendelian genetics: dominant/recessive alleles, genotype vs phenotype, Punnett squares; monohybrid 3:1 phenotypic ratio, dihybrid 9:3:3:1; sex-linked traits differ by sex.

Evolution by natural selection requires variation, heritability, differential reproductive success, and time; evidence includes fossils, homology, biogeography, and molecular data.

Ecology levels: organism → population → community → ecosystem → biome → biosphere; energy flows one way through trophic levels with ~10% transfer efficiency.

Biogeochemical cycles (carbon, nitrogen, water, phosphorus) move matter between living and nonliving reservoirs; nitrogen fixation by bacteria is a key step.

Earth's interior layers: crust, mantle, outer core (liquid, generates magnetic field via dynamo), inner core (solid); seismic waves (P and S) reveal structure.

Plate tectonics: divergent boundaries create new crust (mid-ocean ridges), convergent boundaries produce subduction, volcanoes, and mountains, transform boundaries cause earthquakes.

Rock cycle: igneous (cooling magma), sedimentary (compaction/cementation), metamorphic (heat/pressure); the rock type reflects its formation history.

Weathering and erosion: mechanical vs chemical weathering; erosion transports sediment by water, wind, ice, and gravity; deposition builds landforms.

Water cycle: evaporation, transpiration, condensation, precipitation, runoff, infiltration; groundwater stored in aquifers.

Earth–Sun–Moon geometry explains seasons (axial tilt, not distance), lunar phases, eclipses, and tides (gravitational pull of Moon and Sun).

Solar system: terrestrial vs gas/ice giant planets; Kepler's laws describe orbits; gravity (F = Gm₁m₂/r²) governs orbital motion.

Stellar life cycle: nebula → main sequence → red giant/supergiant → white dwarf or neutron star/black hole; H–R diagram relates luminosity and temperature.

Geologic time: relative dating (superposition, cross-cutting, index fossils) and absolute dating (radiometric decay, half-life) establish Earth's ~4.6-billion-year age.

Crosscutting concepts: patterns; cause and effect; scale, proportion, and quantity; systems and system models; energy and matter flows; structure and function; stability and change.

Engineering design cycle: define problem → research → prototype → test → iterate; constraints (cost, safety, materials) shape solutions alongside criteria.

Science–technology–society links: scientific discovery informs technology, technology enables new science, and both raise ethical, economic, and environmental questions.

Risk and benefit analysis uses probability and magnitude; correlation does not imply causation; confounding variables and bias must be considered.

Data literacy: distinguish observational studies from controlled experiments; interpret graphs, error bars, and sample size; recognize misleading scales.

Human impacts: greenhouse gases (CO₂, CH₄) drive climate change; renewable vs nonrenewable resources; conservation and sustainability balance needs with ecosystem limits.

Models are approximations with assumptions and limits; they are revised as evidence accumulates; uncertainty is quantified, not hidden.

Safety hierarchy: know hazards (GHS pictograms), wear goggles and appropriate PPE, never taste or directly smell chemicals; waft to detect odor.

Emergency procedures: locate eyewash, safety shower, fire extinguisher, and exits; report spills and injuries immediately; know the SDS (Safety Data Sheet) contents.

Equipment use: graduated cylinder for volume (read meniscus at eye level), balance for mass, thermometer for temperature, Bunsen burner with proper flame and ventilation.

Heating and glassware: never heat a closed system; use tongs and heat-resistant gloves; inspect glassware for cracks before use.

Measurement uncertainty: report to the precision of the instrument (e.g., ± smallest division); estimate the last digit; record units and significant figures.

Data analysis: mean, median, mode, range, and standard deviation summarize data; outliers should be investigated, not automatically discarded.

Graphing: independent variable on x-axis, dependent on y-axis; line of best fit for trends; slope and intercept carry physical meaning.

Error types: random error affects precision (reduced by averaging), systematic error affects accuracy (requires calibration or correction).