Olympiad Notes: Sorting of Materials | Science Olympiad Class 6 PDF Download

Introduction

• Various objects surround us in our daily lives, each constructed from distinct materials like paper (derived from wood), glass bulbs containing metal filaments, clothing fashioned from silk or cotton, and kitchenware crafted from stainless steel.
• These objects exhibit noticeable differences in appearance, texture, characteristics, and features, illustrating the diversity among materials used in their construction.
• This chapter will delve into an exploration of the unique features exhibited by some of these materials.

Objects and Materials

• Objects encompass tangible items perceivable through sight or touch, such as a water bottle, mirror, table, or clothing material, while materials signify the substance composing these objects, like plastic for a water bottle, glass for a mirror, or wood for a table.
• Understanding the correlation between objects and their constituent materials aids in analyzing the rationale behind a particular material choice for construction. For instance, when crafting spectacles, options like wood, glass, plastic, or gold are available. Wood isn't suitable as it isn't transparent, while gold, aside from being non-transparent, is expensive. The crucial criteria involve a lightweight and transparent material, leading to the selection of either plastic or glass for their suitability and affordability.

Appearance

• Various materials exhibit distinct visual characteristics.
• Some materials possess a lustrous, shiny appearance, while others appear non-lustrous and dull.
• Wood, for instance, falls within the non-lustrous category.
• Metals like iron, aluminum, copper, and gold typically display a lustrous, shiny, and bright appearance, categorizing substances with such visual traits as metals.

Hardness or Smoothness

• Materials possess tactile qualities, manifesting in varying degrees of hardness or softness.
• Soft materials are those that can be easily compressed or scratched. Examples include sponge and cotton.
• Conversely, hard materials are challenging to compress, cut, or break. Examples of hard materials include iron and copper.

Solubility in water

• When various solutes like salt, sugar, sand, chalk powder, and sawdust are added to water and stirred, different outcomes emerge after waiting for some time.
• Some substances vanish or dissolve entirely in water, while others remain visibly present.
• Soluble substances are those that dissolve or disappear completely in water, such as salt and sugar.
• In contrast, insoluble substances are those that do not dissolve and remain visible when mixed with water, like sand, chalk, and sawdust.

Floatation in water

• Different substances showcase varied behaviors when placed on water—some float while others sink.
• Objects heavier than water tend to sink, whereas those lighter than water float.
• Examples of floating objects include leaves fallen from trees onto pond water, along with light items like a paper boat and thin twigs due to their low weight.
• Conversely, materials such as pieces of stone or heavy bricks are heavier than water, causing them to sink when placed in water.

Transparent Translucent and Opaque

• Transparent objects are materials that permit light to pass through them entirely, enabling clear visibility of objects on the other side. Examples include glass, water, and air.
• Opaque objects, in contrast, do not allow light to pass through them, obstructing the view of objects situated behind them entirely. Materials like wood and metals fall under this category.
• Translucent objects are materials that partially permit light to pass through them, resulting in a blurred or obscured view of objects on the other side. Examples include oily paper, certain types of designed glass, and tissue paper.