lesson
Choose a property that differs
1 · Learn
Separation methods exploit differences in properties. Filtration separates an insoluble solid from a liquid; dissolved particles pass through an ordinary filter with the solvent. Evaporation can recover a dissolved solid when appropriate, while distillation collects condensed solvent after vaporisation.
A method must match the mixture and safety conditions. Heating unknown substances is not a classroom-home experiment. Describe the desired recovered substance before choosing equipment.
2 · Worked example
For a supplied sand-and-salt-water model, filtration removes sand but leaves salt dissolved in the filtrate. Recovering salt needs another suitable separation step.
3 · Your turn
Will ordinary filter paper remove dissolved salt from salt water? Explain.
Check your answer
No. Dissolved salt passes through with the water; filtration removes suitable insoluble particles, not that dissolved solute.
4 · Apply your learning
Plan a separation sequence on paper using a teacher-supplied mixture description; explain each property used.
Adult guidance and safety
Use supplied data and diagrams unless a qualified adult has approved the practical, equipment and risk assessment. No tasting substances, culturing unknown microbes, mains electricity, flames or hazardous chemical experiments at home. Models simplify reality; ask which assumptions affect the conclusion.
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Check a calculation · Year 5 onward
Use this only when your teacher or adult allows a calculator for the task. Show your thinking first. It does not replace mental or written arithmetic and does not mark your lesson answer.
Powers, roots and trigonometry · Year 7 onward
Use only when the task allows a calculator. Choose one operation at a time and record your working. Trigonometry here always uses degrees (DEG), not radians. Inverse sine, cosine and tangent return an angle, not a reciprocal. Keep exact fractions and π in answers when requested.
Approximate numerical results use up to 12 significant digits. Inverse sine returns −90° to 90°, inverse cosine 0° to 180°, and inverse tangent −90° to 90°; these are principal values, not every possible solution of a trigonometric equation.
My observation notebook
Follow your teacher's approved method and safety instructions. Record the sample or supplied dataset, conditions, measurements with units and uncertainties where appropriate. Distinguish observations from explanations. A described experiment is not permission to carry it out; do not improvise equipment or invent missing results.
Ask your teacher for support with the method and recording. A prediction is what you think might happen; an observation is what you actually see, hear or feel safely.
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