General Science
General Science
Basic physics, chemistry and biology at matriculation level: units, states of matter, the human body, plants, electricity and everyday chemistry. The questions are one-liners that reward a memorised fact, and the occasional explanation question rewards a correct chain of reasoning.
Facts to lock in
- SI units: metre (length), kilogram (mass), second (time), newton (force), joule (energy), watt (power), ampere (current), kelvin (temperature).
- Water is H₂O, common salt is NaCl, and carbon dioxide turns limewater milky.
- Photosynthesis needs carbon dioxide, water and sunlight, and produces glucose and oxygen.
- Three states of matter; evaporation cools the surroundings; water boils at 100 °C at sea level.
- Human body: 206 bones in an adult, four chambers in the heart, skin is the largest organ, the stapes in the ear is the smallest bone, normal body temperature about 37 °C.
- Blood has four main groups - A, B, AB and O; O negative is the universal donor.
- Vitamins: A for eyesight, C for scurvy, D for bones, B for beriberi.
- Eight planets; Mercury is nearest the Sun and Jupiter the largest; the Moon is Earth's natural satellite.
- Sound travels faster in solids than in gases and cannot pass through a vacuum.
Worked example
Why does a wet cloth feel cold on the skin? Water evaporating from the cloth absorbs latent heat from the skin, so heat is drawn away and the surface temperature falls. In an explanation question the chain - evaporation, heat absorbed, temperature falls - earns the marks, not the single word evaporation.
Traps
Confusing mass with weight: mass is in kilograms and does not change with gravity, while weight is a force in newtons. Saying the Sun is a planet, or that the Moon makes its own light, are the other two common errors.