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Physics · Class 9
A physics investigation still needs one independent variable, one dependent variable, and control variables held still. Repeats reduce random error. A hypothesis is a testable 'if... then', not a hope. This is the same method idea as chemistry, with metres, seconds, and newtons.
PracticeAn engineer must build something that works in the real world. Cost, safety, time, and materials all matter. A crane must lift scrap and also drop it. A clinic thermometer must not shatter and must be readable. That is more than knowing the formula.
PracticeA law is a short, reliable pattern, often an equation. It tells what happens, again and again, in a stated range. It does not by itself tell the full story of why. Hooke's law: F = k x (only up to a limit). Newton's second law: F_net = m a (for ordinary speeds and sizes). Energy is conserved.
PracticeScience asks why: why does a current make a magnetic field? After we understand it, technology is the useful object or method: the electromagnet, the electric motor, the generator, the thermometer. A straw "sucks" because we understood air pressure, not because of magic.
Practice