One-Liners to Remember

Physics

• SI unit of force: newton; of energy: joule; of power: watt.
• Acceleration due to gravity: 9.8 m/s^2. Speed of light: 3 x 10^8 m/s. Speed of sound in air: about 340 m/s.
• Sound needs a medium; light does not. Sound is fastest in solids.
• Audible range: 20 Hz to 20,000 Hz.
• Concave mirror: shaving mirror, headlights. Convex mirror: rear-view mirror.
• Myopia: concave lens. Hypermetropia: convex lens.
• Blue sky: scattering. Red danger signal: scatters least.
• Ammeter in series; voltmeter in parallel. Household circuits: parallel.
• Motor: electrical to mechanical. Generator: mechanical to electrical.
• Water is densest at 4 C. Normal body temperature: 37 C or 98.6 F.
• Hottest planet: Venus. Largest: Jupiter. Smallest: Mercury. Red planet: Mars.
• Geostationary orbit: 36,000 km.

Chemistry

• pH of pure water: 7. Blood: about 7.4. Stomach: about 1.5 to 3.
• Atomic number = protons. Mass number = protons + neutrons.
• Hardest substance: diamond. Best conductor: silver. Liquid metal: mercury. Liquid non-metal: bromine.
• Most abundant element in Earth's crust: oxygen. Most abundant metal: aluminium.
• Most abundant gas in air: nitrogen (78%).
• Baking soda: NaHCO3. Washing soda: Na2CO3. Plaster of Paris: CaSO4.1/2 H2O. Bleaching powder: CaOCl2.
• Rusting needs air and water. Sodium is kept in kerosene; phosphorus under water.
• Alkane: CnH2n+2; alkene: CnH2n; alkyne: CnH2n-2.
• Noble gases have a complete outer shell. Helium fills balloons safely.
• Dry ice is solid CO2. Laughing gas is nitrous oxide. Marsh gas is methane.

Biology

• Powerhouse of the cell: mitochondria. Suicide bag: lysosome. Protein factory: ribosome.
• Hooke: cell. Brown: nucleus. Mendel: heredity. Darwin: evolution.
• Largest gland: liver. Largest organ: skin. Longest bone: femur. Smallest bone: stirrup.
• Universal donor: O. Universal recipient: AB.
• Vitamin deficiency: A night blindness; B1 beri-beri; C scurvy; D rickets; K bleeding.
• Iodine deficiency: goitre. Iron: anaemia. Calcium: weak bones.
• Malaria: Anopheles. Dengue: Aedes. AIDS: HIV. TB: BCG vaccine.
• Humans: 46 chromosomes. Sex: XX female, XY male.
• Insulin: pancreas. Thyroxine: thyroid. Adrenaline: adrenal.
• Xylem: water; phloem: food. Photosynthesis in chloroplasts.
• Hangul: Dachigam. Snow leopard: Hemis.
• Biomagnification: DDT. Food chain energy: 10% law.