Class6 science materials around us question answer

What are the different types of materials based on their properties? Materials can be classified based on properties like hardness, solubility, transparency, and state. Common classifications include:

• Solids, Liquids, and Gases (states of matter)
• Hard and Soft materials
• Soluble and Insoluble materials
• Materials that can be compressed and those that cannot
• Transparent, Translucent, and Opaque materials
• Metals and Non-metals

What are transparent, translucent, and opaque materials? Give examples.

• Transparent materials allow light to pass through them completely, so we can see objects clearly through them. Example: Glass, water, air.
• Translucent materials allow some light to pass through them, but not all. Objects seen through them appear blurred. Example: Butter paper, frosted glass, thin plastic.
• Opaque materials do not allow any light to pass through them. We cannot see through them. Example: Wood, cardboard, metal.

What is solubility? Give examples of soluble and insoluble substances. Solubility is the ability of a substance to dissolve in a solvent, usually water.

• Soluble substances dissolve in water. Example: Salt, sugar, alum.
• Insoluble substances do not dissolve in water. Example: Sand, stone, oil.

What are metals and non-metals? Give examples.

• Metals are typically hard, shiny, good conductors of heat and electricity, and can be drawn into wires or hammered into sheets. Example: Iron, copper, gold, aluminum.
• Non-metals have varied properties; they are usually not shiny, are poor conductors of heat and electricity, and cannot be drawn into wires or hammered into sheets. Example: Coal, sulfur, oxygen, nitrogen.

Why are cooking utensils usually made of metals? Cooking utensils are usually made of metals because metals are good conductors of heat. This allows heat to be transferred efficiently from the stove to the food, cooking it faster.

Why can we see through glass but not through a wooden plank? Glass is a transparent material, meaning it allows light to pass through it. A wooden plank is an opaque material, meaning it does not allow light to pass through it. This is why we can see through glass but not through wood.

What are the different states of matter? Matter exists in three main states: solid, liquid, and gas.

• Solids have a definite shape and volume.
• Liquids have a definite volume but take the shape of their container.
• Gases have neither a definite shape nor a definite volume; they fill the entire container.

What happens when a substance dissolves in water? When a soluble substance dissolves in water, its particles spread out evenly among the water molecules, forming a solution. The substance is no longer visible as separate particles.

Give examples of materials that are hard and soft.

• Hard materials: Diamond, iron, stone.
• Soft materials: Cotton, foam, chalk.

What is compression? Which state of matter can be compressed easily? Compression is the process of reducing the volume of a substance by applying pressure. Gases can be compressed easily because their particles are far apart. Solids and liquids are generally difficult to compress.