Suman dissolved common salt and sugar in water. She observed that some fine particles were still floating in water. On heating for 4-5 minutes, she found that the solution became almost clear and the fine floating particles totally disappeared. Explain to Suman about the phenomenon involved.
Important Questions on Sorting Materials into Groups
Aim: To classify objects
Materials required: a pencil, a notebook.
Procedure: Look at various objects present in your surroundings and group them as directed in the table.
Observation: Prepare a table with the following headers. Fill it up with the names of appropriate objects.
| Things used for playing | Things used in school | Things found in the kitchen | Things used in the construction |
Conclusion: We group or classify things according to their use.
Aim: To name some objects made of specified materials
Material required: a pencil
Procedure: Some materials are listed below in the table. Name a few objects made from these materials. One, in each case, has been given for your ready reference.
Observation: Complete the table.
| S. No. | Materials | Objects |
| 1. | paper | book, _____, ______, _____. |
| 2. | leather | jacket, ______. ______, ______. |
| 3. | stainless steel | plate, ______, _______. _____. |
Conclusion: From the above table, we conclude that a number of products can be made from the same material.
Aim: To name some materials that can be used to make specified objects
Material required: a pencil
Procedure: Think of different materials from which the objects listed below can be made.
Observation: Fill in the correct information in the following table.
| S. No. | Objects | Materials which can be used to make the object |
| 1. | Utensils | |
| 2. | Table/chair | |
| 3. | Flooring | |
| 4. | Almirah |
Conclusion: Thus we find that different materials can be used for making an object.
Aim: To classify on the basis of the states of matter
Material required: a pencil
Procedure: Study the list of objects given below and classify them on the basis of their state.
air, lemonade, hydrogen, common salt, petrol, talcum powder,
orange juice, oxygen, book, nitrogen, pencil, kerosene
Observation: Complete the table.
| Solid | Liquid | Gas |
Conclusion: Objects around us can be in the solid, liquid or gaseous state.
Aim: To classify objects into natural and man-made ones
Material required: a pencil
Procedure: Classify the objects named below into two groups—natural objects and man-made objects.
Silver, coal, plastics, cotton, cement, soap, gold, bangles
Observation: Complete the table.
| Natural objects | Man-made objects |
Conclusion: Some objects around us are natural, while others are man-made.
Aim: To classify materials on the basis of their solubility
Materials required: a beaker, water, stirrer, a little quantity of the following items—milk, sand. wax, sugar, washing soda, common salt, plastic, glass, coconut oil, paper
Procedure: Put a little quantity of the substances, one at a time, mentioned in the table in a beaker containing water. Use a stirrer to stir. Use fresh water every time to check the solubility of the substance.
Observation: Now, classify the materials on the basis of their solubility in water.
| S. No. | Materials | Soluble in water |
| 1. | milk | yes |
| 2. | sand | no |
| 3. | wax | |
| 4. | sugar | |
| 5. | washing soda | |
| 6. | common salt | |
| 7. | plastic | |
| 8. | glass | |
| 9. | coconut oil | |
| 10. | paper |
Conclusion: We can classify substances on the basis of their solubility in water.
