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ATP EducationScience Exploration Notes Class 9 English Medium 2026-27
Science Exploration Notes Class 9 English Medium 2026-27 now available for students studying in cbse school, up board, state boards and international cbse schools and Latest CBSE Curriculum based on NCERT books.
Science Exploration Notes Class 9 English Medium 2026-27
All topics of Chapter 5
1. Chapter Review and Key Points 2. Pure Substance And Mixture 3. Solution and Its Components 4. Various Filtration Methods 5. Tyndall Effect 6. Advanced Notes / Exam Booster 7. Assignments - What Have You Learned?Science Exploration Chapter 5. Exploring Mixtures and their Separation
CBSE Notes New Syllabus: Class 9
Assignments - What Have You Learned?
Chapter 5. Exploring Mixtures and their Separation
This section explains the different physical methods used for separating the components of mixtures. These methods are selected according to the properties of the substances such as particle size, density, solubility, boiling point and magnetic nature.
17. Principles of Separation
Different mixtures require different separation methods because the components differ in their physical properties. By selecting a suitable method, useful substances can be recovered without changing their chemical nature.
Physical Properties Used for Separation
- Particle Size – Used in filtration and sieving.
- Density – Used in sedimentation, decantation and separating funnel.
- Solubility – Used in crystallisation and evaporation.
- Boiling Point – Used in distillation and fractional distillation.
- Magnetic Property – Used to separate magnetic substances from non-magnetic substances.
18. Sedimentation
When a mixture of an insoluble solid and a liquid is left undisturbed, the heavier solid particles settle at the bottom due to gravity.
Definition
Sedimentation is the process in which heavier insoluble particles settle at the bottom of a liquid under the action of gravity.
Applications
- Removing sand from muddy water.
- Purification of river water.
- Water treatment plants.
19. Decantation
After sedimentation, the clear liquid present above the settled particles is carefully poured into another container.
Definition
Decantation is the process of separating a clear liquid from settled solid particles by carefully pouring it into another container.
Applications
- Separating muddy water.
- Removing oil floating over water.
- Laboratory separation processes.
20. Filtration
Filtration is used to separate insoluble solid particles from a liquid by passing the mixture through a filter medium.
Definition
Filtration is the process of separating insoluble solids from liquids using filter paper or another porous material.
Main Parts
- Residue – Insoluble solid left on the filter paper.
- Filtrate – Clear liquid that passes through the filter paper.
Applications
- Preparing tea.
- Water purification.
- Laboratory experiments.
21. Evaporation
Evaporation is commonly used to obtain dissolved solids from a solution. During this process, the solvent changes into vapour, leaving the dissolved solid behind.
Definition
Evaporation is the process of converting a liquid into vapour to obtain the dissolved solid.
Applications
- Obtaining common salt from seawater.
- Preparation of crystals.
- Chemical industries.
22. Crystallisation
Crystallisation is used to obtain pure solid crystals from a saturated solution. It is preferred when a pure solid is required.
Definition
Crystallisation is the process of obtaining pure crystals of a substance from its saturated solution.
Advantages
- Produces Pure Crystals
- Removes Soluble Impurities
- Prevents Decomposition of Heat-sensitive Solids
Applications
- Preparation of copper sulphate crystals.
- Purification of common salt.
- Manufacture of medicines.
23. Difference Between Evaporation and Crystallisation
| Evaporation | Crystallisation |
|---|---|
| Obtains dissolved solid by removing the solvent. | Obtains pure crystals from a saturated solution. |
| Purity may be lower. | Produces highly pure crystals. |
| Simple and faster. | Requires slow cooling and crystal formation. |
| Used for common salt production. | Used in laboratories and industries. |
24. Centrifugation
Centrifugation is used to separate very fine suspended particles from a liquid by spinning the mixture at high speed.
Definition
Centrifugation is the process of separating substances based on differences in density using rapid spinning.
Applications
- Separating cream from milk.
- Blood testing in laboratories.
- Medical and research laboratories.
25. Magnetic Separation
Magnetic separation is used when one component of a mixture is magnetic while the other is non-magnetic.
Definition
Magnetic separation is the process of separating magnetic materials from non-magnetic materials using a magnet.
Applications
- Separating iron filings from sand.
- Recycling industries.
- Mining operations.
26. Choosing the Correct Separation Method
| Mixture | Suitable Method |
|---|---|
| Sand + Water | Filtration |
| Muddy Water | Sedimentation and Decantation |
| Salt + Water | Evaporation / Crystallisation |
| Milk + Cream | Centrifugation |
| Iron Filings + Sand | Magnetic Separation |
ATP Education Tip
For CBSE examinations, remember the principle behind each separation technique instead of only memorising its name. Filtration → Particle Size, Sedimentation → Density, Evaporation → Volatility of Solvent, Crystallisation → Difference in Solubility, Centrifugation → Density Difference, Magnetic Separation → Magnetic Property. Selecting the correct method for a given mixture is one of the most frequently asked competency-based questions.