Toyama Prefectural Public High School Entrance Examination - Science cheat sheet

When the net force on an object is zero, the object stays at rest or moves at constant velocity; a nonzero net force causes acceleration in the direction of that force.

Speed = distance ÷ time; pressure = force ÷ area; work = force × distance moved in the direction of the force; power = work ÷ time.

Ohm's law: V=IR. In a series circuit the current is the same everywhere and total resistance R=R1+R2; in a parallel circuit the voltage is the same across branches and 1/R=1/R1+1/R2.

Electrical power P=VI=I²R=V²/R; electrical energy in joules = power in watts × time in seconds.

Light reflects so that the angle of incidence equals the angle of reflection; when entering a denser medium a ray bends toward the normal and its speed decreases.

A convex lens converges rays parallel to its principal axis at the focal point; an object beyond 2F gives a real, inverted, diminished image, while an object within F gives a virtual, upright, magnified image.

Sound requires a medium and travels at about 340 m/s in room-temperature air; frequency determines pitch and amplitude determines loudness.

Energy is conserved but can degrade to less useful forms; gravitational potential energy increases with mass and height, and kinetic energy increases with mass and with speed squared.

A pure substance has a fixed composition; a mixture can be separated by filtration, distillation, or recrystallization; an element cannot be decomposed chemically into simpler substances.

A chemical change produces new substances and may show gas, precipitate, color change, heat, or light; a physical change alters only state, shape, or size.

Law of conservation of mass: the total mass of reactants equals the total mass of products; chemical equations are balanced by adjusting coefficients only.

Combination: A+B → AB; decomposition: AB → A+B; oxidation gains oxygen or loses electrons, while reduction loses oxygen or gains electrons.

Ions: cations are positive (Na⁺, Mg²⁺) and anions are negative (Cl⁻, OH⁻); ionic compounds are electrically neutral and conduct electricity when molten or dissolved.

Acids release H⁺ in water and bases release OH⁻; neutralization is H⁺+OH⁻ → H2O, producing a salt; pH below 7 is acidic, 7 is neutral, and above 7 is basic.

Exothermic reactions release heat, as in combustion, neutralization, and rusting; endothermic reactions absorb heat, as in thermal decomposition of calcium carbonate; catalysts lower activation energy.

Gas tests: oxygen relights a glowing splint, carbon dioxide turns limewater milky, hydrogen burns with a pop, and chlorine bleaches damp litmus paper.

Plant cells have a cell wall, chloroplasts, and a large vacuole; animal cells lack these, but both have a nucleus, cytoplasm, cell membrane, and mitochondria.

Photosynthesis: 6CO2+6H2O → C6H12O6+6O2 in chloroplasts using light; respiration: C6H12O6+6O2 → 6CO2+6H2O, releasing energy.

Roots absorb water and minerals; xylem carries water upward, phloem transports sugars, and stomata in leaves allow gas exchange and transpiration.

Human digestion breaks starch to glucose with amylase, protein to amino acids with protease, and fat to fatty acids and glycerol with lipase; villi increase absorption area.

Arteries carry blood away from the heart, veins carry it toward the heart, and capillaries exchange materials; red blood cells carry oxygen using hemoglobin.

Mitosis produces identical body cells; meiosis produces gametes with half the chromosome number; fertilization restores the diploid chromosome number.

Mendel's principle: a dominant allele masks a recessive allele; genotype is the allele pair and phenotype is the observable trait, predictable with Punnett squares.

Evolution by natural selection requires variation, inheritance, selection pressure, and differential reproduction; fossils and homologous structures provide evidence.

Sedimentary rocks form in layers; the principle of superposition states that in undisturbed layers the lower layer is older, and fossils help determine relative ages.

Igneous rocks: plutonic rocks such as granite cool slowly underground with large crystals; volcanic rocks such as basalt cool quickly at the surface with small crystals.

Weathering breaks rock, erosion transports fragments, and deposition forms layers; limestone is mainly CaCO3 and reacts with dilute acid.

The earthquake focus is underground and the epicenter is directly above it; P waves arrive first and are longitudinal, while S waves are slower and cannot pass through liquids.

Magnitude measures earthquake energy, while seismic intensity measures the strength of shaking at a particular location; undersea earthquakes can generate tsunamis.

Basaltic magma is fluid and tends to form shield volcanoes; granitic magma is viscous and can erupt explosively; pyroclastic flows are fast and deadly.

Wind flows from high pressure to low pressure; air pressure decreases with altitude; fronts form where air masses meet, and cumulonimbus clouds bring thunderstorms.

Earth's rotation causes day and night; revolution and axial tilt cause seasons; Moon phases depend on the sunlit half visible from Earth, and solar eclipses occur at new moon.