Exploration: Entering the World of Secondary Science
How science works: models, precise language and units, maths as relationships, laws, theories and principles, predictions, estimation and testing claims.
Key ideas
A scientific model is a simplified picture that keeps only what matters for the question, such as a car treated as a point on a long journey.
Science uses precise symbols and standard (SI) units so that everyone measures and communicates the same way; mixing units causes real mistakes.
An equation shows how quantities are related: if y depends on the square of x, doubling x makes y four times as large.
A law describes a pattern, a theory explains why it happens, and a principle is a broad guiding idea like the conservation of energy.
A prediction is a reasoned expectation from evidence; when it fails, scientists look deeper. No theory is final.
A rough estimate, made by multiplying sensible round numbers, shows the size of an answer and catches big mistakes.
To check a claim, turn it into a testable question and design a fair test that changes only one thing.
Remember
Speed
km/h × 5/18 = m/s
Prefixes
kilo = 103, centi = 10−2, milli = 10−3, micro = 10−6
Volume
1 L = 1,000 mL; 1 m3 = 1,000 L
Scaling
y ∝ x2 and x doubles → y × 4; y ∝ 1/x and x doubles → y halves
Watch out
Thinking a theory is just a guess (it is a well-tested explanation).
Treating a model as an exact copy of the real thing.
Writing an estimate with too many digits, or forgetting the unit.
Worked example
The kinetic energy of a moving ball is 80 units, and it depends on its speed, as its square. Find the new kinetic energy if its speed becomes 1/2 of what it was.