Solve the following crossword puzzle with the help of the clues given below.
Across
5. Completely dissolves in water (7)
6. A transparent substance (3)
7. Can be opaque or translucent (7)
10. The quality of substance that allows us to see through it (12)
11. A substance which is less dense than water (3)
Down
1. An act of sorting out or grouping things (14)
2. A substance used as a standard to check solubility (5)
3. An opaque object (4)
4. Ability of a material to mix uniformly (10)
6. External look of an object (10)
8. Degree to which a substance is dense (7)
9. Hardest substance known (7)
Across
5. Completely dissolves in water (7)
6. A transparent substance (3)
7. Can be opaque or translucent (7)
10. The quality of substance that allows us to see through it (12)
11. A substance which is less dense than water (3)
1. An act of sorting out or grouping things (14)
2. A substance used as a standard to check solubility (5)
3. An opaque object (4)
4. Ability of a material to mix uniformly (10)
6. External look of an object (10)
8. Degree to which a substance is dense (7)
9. Hardest substance known (7)
Important Questions on Grouping Materials of Different Kinds
To understand classification of things which are made of more than one kind of materials
• Observe things like plates, pens, furniture, table mats, doors, water containers, jackets, etc.
• Identify the materials they are made of.
• Record your observations in the table given below.
• Add three more things to the list.
Things made of different types of materials
| S. No. | Things | Material it is made up of |
| 1. | Plates | Steel, glass, plastic or paper |
| 2. | Pens | |
| 3. | Furniture | |
| 4. | Table mats | |
| 5. | Doors | |
| 6. | Water containers | |
| 7. | Jackets | |
| 8. | ||
| 9. | ||
| 10. |
To understand classification of different types of things that are made of same material
• Think about different things that are made of the same material like cotton, leather, paper, plastic, metal and wood.
• Record your observations in the table given.
• One example of each is given. Add more things to the list in the given table.
Different things that are made of same material
| S. No. | Material | Things made of this material |
| 1. | Cotton | Saris |
| 2. | Leather | Jackets |
| 3. | Paper | Books |
| 4. | Plastic | Plate |
| 5. | Metal | Pen |
To observe appearance of different items
• Observe carefully a sheet of paper, cardboard, metallic chain, cotton, silk, wood, chalk, copper wire, aluminium foil and steel utensils.
• Which of these have shiny appearance?
• You may add more items to the list from your surroundings.
• Record your observations in the table given below.
Appearance of different items
| S. No | Items | Appearance |
| 1. | Paper | Dull |
| 2. | Metallic chain | Shiny |
| 3. | Cardboard | |
| 4. | Cotton | |
| 5. | Silk | |
| 6. | Wood | |
| 7. | Chalk | |
| 8. | Copper wire | |
| 9. | Aluminium foil | |
| 10. | Steel utensils |
To observe whether different materials are soluble or insoluble in water
• Think about the materials like salt, sugar, chalk powder, sand, kerosene oil, vinegar, lime juice and cooking oil.
• Identify whether they are soluble or insoluble in water.
• Record your observations in the table given below.
Soluble and insoluble materials
| S. No. | Materials | Soluble or insoluble |
| 1. | Salt | Soluble |
| 2. | Chalk powder | Insoluble and settles down |
| 3. | Kerosene oil | Insoluble and forms separate layer |
| 4. | Sugar | |
| 5. | Sand | |
| 6. | Vinegar | |
| 7. | Lime juice | |
| 8. | Cooking oil |
