General Science
What the questions cover
General Science tests breadth, not depth. Expect life science (cell structures, photosynthesis and respiration, DNA and heredity, ecosystems, human body systems), chemistry (atomic structure, the periodic table, physical vs chemical change, states of matter, acids and bases), physics (Newton's laws, work and energy, heat transfer, waves, simple circuits), and earth/space science (the water cycle, rock types, plate tectonics, seasons, moon phases, planets).
Traps to watch
- Reversing reactants and products: photosynthesis takes in carbon dioxide and water and releases oxygen and glucose; respiration does the reverse.
- Confusing mass and weight. Mass is the amount of matter and does not change with location; weight is a force that changes with gravity.
- Reading the pH scale backwards. Below 7 is acidic, above 7 is basic, and each whole step is a tenfold change in hydrogen ion concentration.
- Mixing up independent and dependent variables, or calling a hypothesis a theory.
- Confusing mitosis (body cells, two identical daughter cells) with meiosis (sex cells, four cells with half the chromosomes).
Rule of thumb
Density links mass and volume and appears constantly: density = mass divided by volume. A block with a mass of 40 g and a volume of 5 cm cubed has a density of 8 g per cm cubed. Asked whether it floats in water (1 g per cm cubed), the answer is no, because 8 is greater than 1. Write the units first, then divide.