Separate a mixture
🎯 Try it
Which method recovers water from salt solution?
📝 Start with the product you want
Ask: What is mixed? Is anything dissolved? Which component must be recovered? These are planning examples; heating and chemical work require an appropriate supervised setting.
📝 Worked decision
A learner filters salty water hoping for fresh water. The salt is dissolved and passes through ordinary filter paper. Distillation can collect the water; evaporation alone loses it to the surroundings.
📝 Multi-step challenge
Separate sand and salt from a dry mixture: add enough water to dissolve salt; filter to collect sand; recover salt from the filtrate by controlled evaporation/crystallisation. Explain the order. Keep recovered materials for observation, not eating.
Write the chosen method, relevant property, and desired product for each new problem.
✅ Check your understanding
Why does sand remain on filter paper?
📝 Choose a method for a different goal
You have sand mixed with salty water and want to collect both the sand and the water. Plan two separation stages in order. Name what moves on to the second stage and what remains there.
🔑 Worked answer
Filter first to retain sand. The filtrate is salt solution. Distil that filtrate to collect condensed water; salt remains in the distillation vessel. Ordinary filter paper does not remove dissolved salt. This is a supervised laboratory plan, not a drinking-water safety test.