Why can’t we filter salt from salt water in Separation of Substances – Class 6 Science Experiment

Chapter Name: Separation of Substances

Activity Name: Why can’t we filter salt from salt water in Separation of Substances

Activity Description:

The experiment aims to understand why it is not possible to filter salt from saltwater using filter paper. By dissolving salt in water and attempting to filter the mixture, students will observe that the salt particles do not get separated from the saltwater solution.

Required Items:

1. Beaker
2. Water
3. Salt
4. Filter paper

Step by Step Procedure:

1. Take a beaker and pour water into it.
2. Add some salt to the water and stir well to dissolve the salt completely, creating a saltwater solution.
3. Fold the filter paper into a cone shape and place it in a filter funnel.
4. Hold the filter funnel over a clean container or another beaker to collect the filtered liquid.
5. Carefully pour the saltwater solution into the filter funnel.
6. Observe and note down the results.

Experiment Observations:

Upon filtering the saltwater solution, you will notice that the salt particles do not get separated from the water. The filtered liquid collected in the container will still contain dissolved salt, indicating that the salt particles are too small to be filtered out by the filter paper.

Precautions:

• Handle the glassware and equipment with care to avoid any accidents or breakage.
• Ensure that the filter paper is properly placed in the filter funnel to prevent any leakage or loss of the sample.

Lesson Learnt from Experiment:

The experiment demonstrates that salt particles dissolved in water are too small to be filtered out by a filter paper. The experiment highlights the concept that the particles of salt are much smaller than the pores of the filter paper, making it impossible to physically separate the salt from the saltwater solution using this method.

This observation emphasizes the need for alternative methods, such as evaporation or distillation, to separate dissolved substances from a solution.