Primary science: living systems, matter, energy, Earth and evidence
Evidence and explanation
Primary science connects observation, comparison, measurement and explanations that can be tested against evidence. A prediction states an expected result under specified conditions; it is not proof before a test. In a fair comparison, identify which factor is changed, which outcome is measured and which relevant conditions should remain comparable. Investigation is not always a rigid sequence: unexpected results can require a revised question, repeated measurement or another explanation. Correlation alone does not establish causation.
Matter and energy
A material’s observable properties can help classify it or choose a use. A physical change such as melting changes state without necessarily creating a different substance. A chemical change forms different substances, though no single visible sign proves every case on its own. Mass, volume and density are related but distinct; calculations need consistent units and a defined sample. Heat can transfer through conduction, convection and radiation. Radiation does not require direct material contact, while convection involves moving fluid. Electrical conductors and insulators differ in their ability to carry charge under stated conditions; classroom descriptions do not authorize work on live circuits.
Living systems
Plants and animals have structures serving functions, but not every member of a broad group looks identical. Photosynthesis uses light energy to support the production of organic matter, while cellular respiration releases usable energy from chemical compounds; plants also respire. Food chains and webs represent feeding relationships and energy transfer. An arrow convention must be stated, commonly showing energy moving from a food source to its consumer. Decomposers contribute to nutrient cycling rather than creating energy from nothing.
Organisms interact with habitats through resources, competition and changing conditions. A population is not the same as an entire ecosystem. Simple health and hygiene concepts can be taught without diagnosing an individual or recommending a drug. Body systems work together; a single symptom cannot establish a medical condition in an educational exercise.
Earth, space and environment
Earth’s rotation contributes to day and night, while its axial tilt and orbit explain seasonal differences in sunlight. Seasons are not caused simply by Earth moving much closer to the Sun. Evaporation, condensation, precipitation and water movement form connected processes; the cycle does not require every water particle to follow one identical route. Weather describes conditions over shorter periods, while climate concerns longer-term patterns.
Apply knowledge responsibly
Distinguish an observed fact, a model and a proposed explanation. Read a diagram’s labels and units before interpreting it, and avoid turning one local example into a claim about every organism or place. Use supplied materials and approved demonstrations; no chemical procedure, electrical connection or clinical treatment is inferred from a multiple-choice answer. These are common primary-science foundations rather than an asserted current national assessment blueprint.