Filtration: cleaning muddy water
Filter muddy water and salty water. Discover what filter paper can and cannot remove.
Core concept
In short: Pour muddy water through a filter to get clean water and leave the mud behind.
Filtration separates insoluble solids from liquids
Topic: Separation of mixtures
A mixture: Two or more substances mixed together, which can be separated again. All key words contains two or more substances that are not chemically joined, so they can be separated again. filtration: Separating solid bits from a liquid by pouring it through filter paper or cloth. All key words pours a mixture through filter paper. The tiny holes in the paper let liquid and dissolve: To mix into a liquid so completely that you can no longer see the pieces. All key words particle: A tiny piece that matter is made of, far too small to see. All key words 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
- Add 5 g of soil to the water in Beaker A and stir to make muddy water.
- Add 5 g of salt to the water in Beaker B and stir to make salt water.
- Filter Beaker A into Flask A.
- Filter Beaker B into Flask B.
- 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.