Sedimentation, Decantation and Filtration
Class 6 Science · Chapter 9: Methods of Separation in Everyday Life · NCERT Curiosity section Ch 9
Learn
After heavy rain, the tap water in Farhan's village is muddy. His mother fills a bucket and leaves it still for a few hours. The heavy mud slowly settles at the bottom: sedimentation.
Then she gently pours the clearer water from the top into another vessel, without disturbing the mud: decantation. Some fine particles may still float in it.
To remove those, she pours the water through a folded clean cloth or filter paper. The tiny particles stay on the filter; clear water drips through: filtration. To make it safe to drink, the water should then be boiled or purified to kill germs.
Explore: clean the muddy water.
- Put the steps in order.
Remember
- Sedimentation: heavy insoluble particles settle. Decantation: pour off the liquid above.
- Filtration removes fine particles using a filter; boil water to make it safe.
Quick check
Pouring off the clear liquid after the solid has settled is called …
- decantation
- sedimentation
- evaporation
- churning
Answer
decantation. Settling is sedimentation; pouring off is decantation.
Think about it
Does filtration remove salt from salty water? Why not?
One answer
No. Salt is dissolved, so its tiny particles pass through the filter with the water. Filtration only removes insoluble particles.
Practice
Practise with fresh questions at three levels (easy, medium, hard), some answered hands-on, with hints and worked answers. Get 4 of your last 5 right to finish the topic.