This method separates magnetic materials from non-magnetic ones using a magnet.

When to use it

Use magnetic separation when one component is attracted to a magnet and the other is not.

Experiment: Separating iron filings from sulphur

Materials needed:

• Iron filings
• Powdered sulphur
• Magnet
• Sheet of paper

Procedure:

1. Mix a small amount of iron filings with sulphur on a clean sheet of paper.
2. Hold the magnet over the mixture and move it gently.
3. Observe what happens to the iron filings and the sulphur.
4. Collect the iron filings that stick to the magnet.

Result: The iron filings are attracted to the magnet and are pulled away from the sulphur. The sulphur remains on the paper.

This method separates an insoluble solid from a liquid using a filter paper and funnel.

When to use it

Use filtration when you have a solid that does not dissolve in a liquid (heterogeneous mixture).

Experiment: Separating clay soil from water

Materials needed:

• Clay soil
• Water
• Filter paper
• Funnel
• Beaker
• Stirring rod

Procedure:

1. Fold the filter paper and place it in the funnel. Wet it with a little water to stick it to the funnel.
2. Mix clay soil with water in a beaker to make a muddy mixture.
3. Pour the mixture slowly along a stirring rod into the funnel.
4. Collect the filtrate (clear liquid) in a beaker. The residue (clay soil) stays on the filter paper.

Result: The water passes through the filter paper as filtrate, while the clay soil is retained as residue.

This method separates a soluble solid from its solution by heating to remove the liquid.

When to use it

Use evaporation when a solid is dissolved in a liquid and you want to recover the solid.

Experiment: Recovering salt from salt solution

Materials needed:

• Salt solution (salt dissolved in water)
• Evaporating dish
• Heat source (Bunsen burner or spirit lamp)
• Tripod and wire gauze

Procedure:

1. Pour the salt solution into a clean evaporating dish.
2. Heat the solution gently using a Bunsen burner.
3. Continue heating until all the water evaporates and only solid salt remains.
4. Allow the dish to cool before collecting the salt crystals.

Result: The water evaporates as vapor, and solid salt crystals remain in the dish.

This method separates a liquid from dissolved substances by boiling and condensing the vapor.

When to use it

Use simple distillation when you want to obtain pure water from a solution containing dissolved salts or impurities.

Experiment: Distilling salty water

Materials needed:

• Salt solution
• Distillation apparatus (or simple setup with test tube, beaker, and ice)
• Heat source
• Beaker for collecting distillate

Procedure:

1. Set up the distillation apparatus. Connect the condenser to the round-bottom flask containing salt solution.
2. Heat the solution slowly. Water vapor rises and enters the condenser.
3. Cool the vapor with running water in the condenser.
4. Collect the condensed liquid (distillate) in a clean beaker.
5. Stop heating when only a small amount of liquid remains in the flask.

Result: Pure water drips out as the distillate. The salt remains in the flask as residue.

This method separates a substance that changes directly from solid to gas from one that does not.

When to use it

Use sublimation when one component sublimes (changes to gas without melting) and the other does not.

Experiment: Separating ammonium chloride from sand

Materials needed:

• Ammonium chloride
• Sand
• Crucible with lid
• Bunsen burner
• Tweezers or forceps

Procedure:

1. Mix a small amount of ammonium chloride with sand.
2. Place the mixture in a crucible and cover with a lid.
3. Heat the crucible gently for a few minutes.
4. Observe the inside of the lid carefully.
5. Turn off the burner and allow to cool. Remove the lid.

Result: White crystals of ammonium chloride deposit on the lid (sublimate). The sand remains at the bottom of the crucible.

This method separates immiscible liquids (liquids that do not mix) based on density differences.

When to use it

Use a separating funnel when you have two immiscible liquids, such as oil and water.

Experiment: Separating kerosene from water

Materials needed:

• Kerosene
• Water
• Separating funnel
• Two clean beakers

Procedure:

1. Pour a mixture of kerosene and water into the separating funnel.
2. Allow the liquids to settle. Two distinct layers form.
3. The denser liquid (water) settles at the bottom, and the less dense liquid (kerosene) floats on top.
4. Open the tap and drain the bottom layer (water) into a beaker.
5. Collect the top layer (kerosene) into another beaker.

Result: The two immiscible liquids are completely separated.

In Tanzania, the method of filtration is used in many households to obtain clean water from muddy river or dam water. People pour water through a clean cloth or filter paper to remove suspended particles before drinking. Similarly, evaporation is used in salt pans along the coast near Dar es Salaam and Zanzibar, where seawater is left in shallow pans to evaporate under the hot sun, leaving behind salt crystals that can be collected and sold in local markets.