- Books Name
- CBSE Class 6 Science Book
- Param Publication
- CBSE Class 6
AIM : To show sedimentation, decantation and filtering process.
Materials required : (i) Water (ii) soil (iii) piece of cloth (iv) filter paper
Method : Mix some soil to water in a glass. Let it stand for half an hour. Observe the water carefully and note the observations. Now, slightly tilt the glass without disturbing the water. Let the water from the top flow into another glass. Now filter the water through a piece of cloth. In a piece of cloth, small holes or pores remain in between the woven threads. These pores in a cloth can be used as a filter. If the water is still muddy, impurities can be separated by a filter that has even smaller pores. A filter paper is one such filter that has very fine pores in it. Solid particles in the mixture do not pass through it and remain on the filter.
(vi) Evaporation :
The process of conversion of water into its vapour below its boiling point is called evaporation. The process of evaporation takes place continuously wherever water is present.
Sea water contains many salts mixed in it. One of these salts is the common salt. When sea water is allowed to stand in shallow pits, water gets heated by sunlight and slowly turns into water vapour, through evaporation. In a few days , the water evaporates completely leaving behind the solid salts. Common salt is then obtained from this mixture of salts by further purification.
AIM : Evaporation of water containing salt.
Materials required : (i) beaker (ii) water (iii) stand (iv) burner
Method : Allow the water to boil as shown. If we continue heating, water disappear completely.
Heating a beaker containing salt water
Now, add two spoons of salt to water in another beaker and stir it well. Heat the beaker containing the salt water. Let the water boil away. In this activity, we used the process of evaporation, to separate a mixture of water and salt. The process of conversion of water into its vapour is called evaporation. The process of evaporation takes place continuously wherever water is present. In this activity water is boiled out as vapours and salt is remained in the beaker.