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Grade 6 Intermediate About 15 min Version 1 Awaiting review Premium

Filtration: cleaning muddy water

A mixture contains two or more substances that are not chemically joined, so they can be separated again. Filtration pours a mixture through filter paper. The tiny holes in the paper let liquid and dissolved particles through, but hold back larger pieces of solid.

What you will learn

  • Use filtration to separate an insoluble solid from a liquid.
  • Identify the residue and the filtrate.
  • Explain why filtration cannot remove a dissolved substance.

Before you start

  • Know the difference between soluble and insoluble solids. Try the Dissolving experiment first.

Materials

  • Water (50 mL in each beaker)
  • Soil
  • Table salt

Equipment

  • 2 beakers (100 mL)
  • 2 conical flasks (150 mL), each with a funnel and filter paper
  • Stirring rod

Procedure

  1. Add 5 g of soil to the water in Beaker A and stir to make muddy water.
  2. Add 5 g of salt to the water in Beaker B and stir to make salt water.
  3. Filter Beaker A into Flask A.
  4. Filter Beaker B into Flask B.
  5. Compare what is left on each filter paper and what collects in each flask.

How this simulation is simplified

  • Filtering is instant. Real filtration can take several minutes.
  • All the liquid passes through and none soaks into the filter paper.
  • The filtrate from muddy water is shown as completely clear. Real filtrate may still be a little cloudy.