MTTC Integrated Science (Elementary) (093) cheat sheet

Testable hypothesis: it must be falsifiable, specify variables, and predict an observable outcome under defined conditions.

Independent variable is manipulated; dependent variable is measured; controlled variables are held constant; confounding variables change with the independent variable.

Accuracy is closeness to a true value; precision is closeness of repeated measurements to one another; reliable measurements are consistent but not necessarily valid.

Observation records what is detected by senses or instruments; inference is a conclusion or explanation based on observations and prior knowledge.

Scientific law describes a consistent relationship (e.g., F = ma); a theory explains mechanisms and is supported by multiple lines of evidence; both can be revised.

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

Control group receives no active treatment or a placebo; randomization distributes variables; blinding reduces expectancy effects.

Graph choice: line graph for continuous change, bar graph for categorical comparisons, scatterplot for relationship between two numerical variables.

Cell theory: all organisms consist of cells; cells are the basic unit of life; new cells arise from preexisting cells.

Prokaryotes lack a membrane-bound nucleus and organelles; eukaryotes have a nucleus and membrane-bound organelles; viruses are not cells.

Photosynthesis: 6CO2 + 6H2O + light energy -> C6H12O6 + 6O2; occurs in chloroplasts using chlorophyll.

Cellular respiration: C6H12O6 + 6O2 -> 6CO2 + 6H2O + ATP; aerobic respiration occurs mainly in mitochondria.

DNA is transcribed to mRNA in the nucleus and translated to protein at ribosomes; codons specify amino acids.

Mitosis yields two identical diploid cells for growth and repair; meiosis yields four haploid gametes with genetic variation.

In Mendelian genetics, a dominant allele masks a recessive allele in heterozygotes; genotype is genetic makeup, phenotype is observable trait.

Natural selection requires heritable variation and differential reproductive success; adaptations increase fitness in a given environment.

Energy flows through ecosystems and matter cycles; producers make organic matter, consumers eat it, decomposers recycle nutrients.

Igneous rock forms from cooling magma or lava; sedimentary rock forms by compaction and cementation of sediments; metamorphic rock forms from heat and pressure without melting.

Plate boundaries: divergent plates move apart and create new crust; convergent plates collide or subduct; transform plates slide past each other.

Water cycle processes: evaporation, transpiration, condensation, precipitation, runoff, infiltration, and groundwater storage.

Earth's interior: crust, mantle, liquid outer core, solid inner core; seismic wave behavior reveals layer properties.

High-pressure systems generally bring clear, sinking air; low-pressure systems bring rising air, clouds, and precipitation; fronts mark air-mass boundaries.

Moon phases arise from the Moon's orbital position relative to Earth and Sun; one lunar cycle averages about 29.5 days.

Seasons are caused by Earth's axial tilt, not distance from the Sun; the tilt changes sunlight angle and day length.

Solar system order: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune; terrestrial planets are rocky, gas giants are large and mostly gaseous.

Relative dating uses superposition and index fossils; absolute dating uses radioactive decay; the Big Bang is supported by redshift, expansion, and cosmic microwave background.

Newton's first law: inertia; an object maintains constant velocity unless a net external force acts.

Newton's second law: F = ma; acceleration is proportional to net force and inversely proportional to mass.

Newton's third law: forces occur in equal and opposite pairs acting on different objects.

Speed = distance/time; acceleration = change in velocity/time; slope of distance-time graph is speed; slope of velocity-time graph is acceleration.

Work = force × distance (force parallel to motion); kinetic energy = 1/2mv²; gravitational potential energy = mgh; energy is conserved.

Wave equation v = fλ; transverse waves oscillate perpendicular to travel, longitudinal waves oscillate parallel.

Ohm's law V = IR; series circuits share current and sum voltage; parallel circuits share voltage and sum current.

Density = mass/volume; physical changes alter form but not composition; chemical changes form new substances and conserve mass in closed systems.

pH below 7 is acidic, 7 neutral, above 7 basic; acids release H⁺ in water, bases release OH⁻ or accept H⁺.