Case Based Questions: Materials Around Us | Science for Class 6 PDF Download

Q1: Read the source and answer the question that follows

Rani and Kiran are in the school yard, testing different objects for their hardness. Rani picks up a rock, and Kiran picks up a rubber ball. Prashant asks which one is harder.
Rani explains that the rock is hard because it doesn’t change shape easily and can scratch softer materials. Kiran adds that the rubber ball is soft because it can be easily compressed or squished. They both agree that hardness is a key property that helps determine how materials are used in construction and everyday objects.

Q1. How do hard and soft materials differ in terms of their properties?
Ans: Hard materials don’t get scratched or bent easily, like rocks. Soft materials, like rubber, can be scratched or bent easily.

Q2. Why is it important to use hard materials in construction?

Ans: Hard materials, like metal and stone, are strong and last longer. They can handle heavy pressure and won’t wear out easily, making them perfect for building things.

Q3. Which of the following materials is considered hard?
A) Rubber
B) Cotton
C) Rock
D) Sponge

Ans: C) Rock

Q2: Read the source and answer the question that follows

Aryan and Meera are in the school lab, observing various materials. Aryan picks up a clear glass, and Meera holds a wooden block. Ria asks them if these materials allow light to pass through.
Meera explains that the glass is transparent, meaning light passes through it, allowing objects on the other side to be seen clearly. Aryan adds that the wooden block is opaque, meaning no light can pass through it. Ria then wonders about a frosted glass window, and Meera explains that frosted glass is translucent, meaning it lets some light through but you can’t see clearly through it.

Q1. What is the difference between transparent, opaque, and translucent materials?

Ans: Transparent materials allow light to pass through clearly (e.g., glass), opaque materials block light completely (e.g., wood), and translucent materials allow some light through but not clearly (e.g., frosted glass).

Q2. Why do we use transparent materials for windows?

Ans: Transparent materials, like glass, are used for windows because they allow light to pass through, so we can see outside while still being protected from the weather.

Q3. Which of the following materials is opaque?
A) Glass
B) Water
C) Wood
D) Butter paper

Ans: C) Wood

Q4. Can you think of other examples of translucent materials used in daily life?

Ans: Other examples of translucent materials include butter paper, shades on lamps, and shower doors, where light passes through but the view is blurred.

Q3: Read the source and answer the question that follows

Neha and Simran are in the kitchen, experimenting with water. Neha adds salt to a glass of water, and it dissolves completely. Simran then adds oil to another glass, and it floats on top. Arjun, who is observing, asks, “Why does salt disappear in water, but oil doesn’t mix?”
Neha explains that salt is soluble in water, meaning it dissolves completely when mixed. Simran adds that oil is insoluble in water, so it forms a separate layer. They both agree that the solubility of a material depends on how it interacts with water.

Q1. What does it mean for a material to be soluble in water?

Ans: A material is soluble in water if it dissolves completely when mixed with water, like salt or sugar.

Q2. Why do some materials dissolve in water, while others do not? What factors influence solubility?

Ans: Some materials dissolve in water because their particles can separate and mix with water molecules, like salt. Others, like oil, do not mix because their molecules do not interact with water molecules. Solubility depends on the chemical properties of the materials.

Q3. Which of the following materials is insoluble in water?
A) Salt
B) Sugar
C) Oil
D) Vinegar

Ans: C) Oil