Worksheet 4: Class 6 Science - Sorting Materials into Groups

Welcome! This worksheet will help you understand the different properties of materials and why it's important to sort them into groups. Let's learn how to classify objects based on their properties!

Why Do We Group Materials?

We see a huge variety of objects around us, made from different materials like wood, plastic, glass, and metal. It would be confusing to study each object individually. So, we group them based on their similarities and properties. Grouping objects makes it easier to study their properties and to use them for specific purposes.

Properties of Materials

Materials have different properties that help us classify them:

• Appearance: Some materials, like gold and iron, are shiny (have **lustre**), while others, like wood and paper, do not.
• Hardness: Materials can be hard or soft. You can easily compress soft materials (like a sponge) but not hard materials (like a stone).
• Solubility: Some substances dissolve in water (**soluble**), like sugar and salt. Others do not (**insoluble**), like sand.
• Transparency: Materials can be **transparent** (you can see through them clearly, like glass), **translucent** (you can see through them partially, like frosted glass), or **opaque** (you cannot see through them at all, like wood).
• Float or Sink: Some objects float on the surface of water, while others sink to the bottom. For example, a dry leaf floats, but a stone sinks.

Understanding these properties is the key to sorting materials correctly.

Practice Questions

1. Fill in the blank: A material that is shiny is said to have _____.

Lustre

2. True or False: A piece of cotton is a hard material.

False. Cotton is a soft material.

3. Match the material with its property:

(a) Glass (i) Opaque

(b) Wood (ii) Transparent

(c) Frosted Glass (iii) Translucent

a - ii, b - i, c - iii

4. What is the difference between a soluble and an insoluble substance? Give an example of each.

A **soluble** substance dissolves in water (e.g., sugar), while an **insoluble** substance does not (e.g., sand).

5. Fill in the blank: A stone will _____ in water, but a dry leaf will _____.

A stone will **sink** in water, but a dry leaf will **float**.

6. Why is a glass tumbler used to hold liquids and not a cloth?

A glass tumbler is **hard**, **transparent**, and **impervious to water**, while a cloth is soft and absorbs water, making it unsuitable for holding liquids.

7. Name three objects that are made of plastic.

A plastic bottle, a plastic bucket, and a plastic toy.

8. What is the main reason we group materials?

We group materials to make it easier to study them and their properties, as well as to use them more efficiently for various purposes.