Science · Class 6
Separation of Substances
Handpicking, threshing, winnowing, sieving, sedimentation, and evaporation.
3 sections15–25 min read6 MCQs · 2 examples
Chapter Overview
Mixtures contain two or more substances that can often be separated by physical methods. This chapter covers handpicking, threshing, winnowing, sieving, sedimentation, decantation, filtration, evaporation, and condensation.
Why Separate?
- Remove unwanted components (stones from rice)
- Obtain useful components (salt from sea water)
- Separate harmful substances
Separation Methods
- Handpicking: by size, colour, shape
- Threshing: grain from stalks
- Winnowing: lighter husk blown away by wind
- Sieving: different particle sizes (flour, sand)
- Sedimentation & decantation: heavier particles settle
- Filtration: solid from liquid through filter paper
- Evaporation: dissolved solid from liquid
- Condensation: gas to liquid (water from steam)
Solved Examples
Step-by-step solutions — read each step before checking the final answer.
Salt from water
How is common salt obtained from sea water?
- 1Sea water is collected in shallow pans
- 2Water evaporates in sunlight
- 3Salt crystals remain behind
Answer
By evaporation
Husk from grain
After threshing, how is husk separated from grain?
- 1Mixture is dropped from height
- 2Wind blows lighter husk away
- 3Heavier grains fall straight down
Answer
Winnowing
Key Points to Remember
- ✓ Physical methods do not change chemical nature
- ✓ Filtration works when solid does not dissolve
- ✓ Churning separates butter from curd
Exam Tips
- • Match method to mixture type in exams
- • Draw labelled diagram of filtration setup
- • Give real-life example for each method
Practice MCQs — Separation of Substances
Test your understanding with topic-wise multiple choice questions. Explanations appear after each answer.
Question 1 of 6Score: 0/0
Winnowing is used to separate: