Separating Mixtures: Sort It Out!

A complete, ready-to-teach KS3 lesson on pure substances and separation techniques, written for Year 7.

Styled as a detective case file, the lesson opens with a big question: how could you get safe drinking water from salty sea water? Pupils solve the case by the final slides.

What’s covered

• Pure substances and mixtures (the science meaning of “pure”)
• Dissolving: solute, solvent, solution, soluble and insoluble
• Filtration: residue and filtrate
• Evaporation and crystallisation
• Distillation, with a labelled diagram
• Chromatography and reading a chromatogram
• Testing purity using melting and boiling points

What’s included

• 12-slide PowerPoint in a case-file style, with a question and answer on every slide
• Teacher notes on every slide, including common misconceptions and source codes
• 4-page worksheet (PDF) with Core, Stretch and Challenge questions and a full answer key
• Homework sheet (PDF, 27 marks) with a full mark scheme
• One-page knowledge organiser (PDF) for revision
• Puzzle pack (PDF): unscramble the key words, fill the gaps and odd one out, with answers
• “Pick the method” exit quiz with answers