Osaka Public High School Entrance Examination - Science cheat sheet

Speed = distance ÷ time; average speed = total distance ÷ total time.

Newton's first law: with no net force, an object stays at rest or moves in a straight line at constant speed.

Weight (N) = mass (kg) × gravitational acceleration (about 9.8 m/s²); mass is unchanged by location.

Pressure P = F ÷ A; for a fixed force, reducing contact area increases pressure.

Work (J) = force (N) × displacement (m) in the direction of the force; power (W) = work ÷ time.

Ohm's law: V = RI; series resistance R = R₁ + R₂; parallel resistance 1/R = 1/R₁ + 1/R₂.

Electric power P = VI = I²R = V²/R; electrical energy = power × time.

Wave relation v = fλ; frequency is set by the source and does not change when the wave enters another medium.

A current-carrying coil produces a magnetic field; reversing the current or increasing the number of turns changes the field direction or strength.

Atomic number = number of protons; in a neutral atom, electrons = protons. Mass number = protons + neutrons.

Ionic compounds consist of positive metal ions and negative nonmetal ions arranged in a crystal lattice.

A balanced chemical equation has equal numbers of each type of atom on both sides, consistent with conservation of mass.

Complete combustion of a hydrocarbon: hydrocarbon + O₂ → CO₂ + H₂O.

Acids produce H⁺ in water; bases produce OH⁻; neutralization: acid + base → salt + water.

pH < 7 acidic, pH = 7 neutral, pH > 7 basic at ordinary temperature.

Metal reactivity order (typical): Mg > Zn > Fe > Cu > Ag; a more reactive metal displaces a less reactive one from its salt solution.

A precipitate forms when ions in solution combine to give an insoluble compound, e.g., Ag⁺ + Cl⁻ → AgCl↓.

Pure substances melt and boil at fixed temperatures; mixtures generally do not.

Cell parts: nucleus, cytoplasm, cell membrane; plant cells also have a cell wall, chloroplasts, and a large vacuole.

Photosynthesis: 6CO₂ + 6H₂O + light energy → C₆H₁₂O₆ + 6O₂, occurring in chloroplasts.

Aerobic respiration: C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + energy, mainly in mitochondria.

Digestive enzymes: amylase breaks starch to maltose; protease breaks proteins to peptides/amino acids; lipase breaks fats to fatty acids and glycerol.

Blood transport: red blood cells carry oxygen using hemoglobin; plasma carries nutrients, carbon dioxide, and wastes.

Mammalian heart: the right side sends blood to the lungs; the left side sends blood to the body; arteries carry blood away from the heart, veins return it.

Reflex pathway: receptor → sensory neuron → spinal cord/brain → motor neuron → muscle or gland.

Meiosis produces gametes with half the chromosome number; fertilization restores the full number.

Food chain arrows show energy flow from producer to consumer; decomposers break down dead matter and recycle nutrients.

Earth's interior: crust, mantle, liquid outer core, solid inner core; S waves cannot pass through the liquid outer core.

Igneous rock forms from cooling magma/lava; sedimentary rock from compacted layers; metamorphic rock from heat and pressure.

Law of superposition: in undisturbed strata, lower layers are older than upper layers.

High pressure: descending air, clear/dry weather; low pressure: rising air, clouds and precipitation.

Cold front: cold air undercuts warm air, causing heavy rain/thunderstorms, then cooler clear weather.

Earth rotates west-to-east once per day, causing day/night; revolution plus axial tilt causes seasons.

Moon phases repeat about every 29.5 days; solar eclipse at new moon, lunar eclipse at full moon.

P waves are fast longitudinal waves; S waves are slower transverse waves; arrival-time difference locates an earthquake.

Star color indicates temperature: blue-white stars are hotter; red-orange stars are cooler.