Short interactive lessons that ask a question before they explain. One session takes about ten minutes and ends with questions to check what you have understood.
A model keeps the few quantities that decide the answer to one question and leaves out the rest, on purpose.
Class 9 · Science How Science Works FreeWords such as work have exact meanings in science, and an equation states how quantities are related.
Class 9 · Science How Science Works FreeA measurement is a number and a unit. One airliner ran out of fuel because pounds were used in place of kilograms.
Class 9 · Science How Science Works FreeA law describes a pattern, a theory explains it, and a principle applies across many situations.
Class 9 · Science How Science Works FreeA prediction is an expected result worked out from evidence. A claim is testable when it names something measurable.
Class 9 · Science How Science Works FreeRough values of each quantity give an answer of the right size, good enough to check a calculation.
Class 10 · Science Reactions, and How We Write Them FreeA reaction forms new substances. A change of state, colour or temperature, or a gas given off, points to one.
Class 10 · Science Reactions, and How We Write Them FreeFrom a sentence to a word equation to formulae. A skeletal equation has correct formulae but unequal atom counts.
Class 10 · Science Reactions, and How We Write Them FreeAtoms are not created or destroyed, so each element must have equal counts on both sides. Change coefficients, never formulae.
Class 10 · Science Reactions, and How We Write Them FreeCombination forms one product from several reactants; decomposition breaks one reactant into several.
Class 10 · Science Reactions, and How We Write Them FreeAn exothermic reaction releases heat; an endothermic one takes heat in. Bond energies decide which.
Class 10 · Science Reactions, and How We Write Them FreeA more reactive metal displaces a less reactive one from a solution of its compound. The reverse does not occur.
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