Master Chapter 6 Class 6 - Materials around us (Curiosity) with comprehensive NCERT Solutions, Practice Questions, MCQs, Sample Papers, Case Based Questions, and Video lessons.
Start Learning NowWelcome to Chapter 6. Our journey begins as we join two students, Ghulan and Sheeta, who are thrilled to be back in their new class after the summer break. They are excited about their new things: a new notebook, a new pen.
Just like them, look around you right now. You are surrounded by objects. In your classroom, you might see a desk, a chair, a window, a duster, a water bottle, and the book you are holding. At home, you have a bed, a television, plates, spoons, and clothes. Our world is filled, absolutely filled, with a countless variety of objects.
This chapter starts with a very simple observation but leads to a very deep question. The chapter opens with an ancient shloka that mentions a crucible (a vessel for melting things) and states that the materials used to make it are clay and iron.
This is the key. Every single object you see is made of something. That "something" is what we call a material.
Your notebook is an object; the paper it is made from is the material.
Your pen is an object; the plastic and metal it is made from are the materials.
The window is an object; the glass and wood (or aluminium) it is made from are the materials.
Any substance that is used to create an object is a material. Our world is not just full of objects; it is full of materials like paper, wood, cloth, glass, metal, plastic, and clay.
This chapter is all about becoming a detective. We are going to stop looking at the objects and start seeing the materials they are made from. We will investigate a simple but powerful question: Why are certain things made of certain materials?
This entire chapter is an investigation into the properties of materials. We will learn that every material has its own set of "rules" or characteristics, and these properties determine what we can use that material for.
Think about it:
Why can't you drink water from a tumbler made of cloth? It seems obvious, but the scientific reason is that the properties of cloth are not suitable for holding water.
Why aren't your cooking utensils at home made of paper or wood? Because those materials do not have the property of handling high heat.
Why is a cricket ball made of hard leather and cork, while a tennis ball is made of rubber and felt? Because they are designed for different purposes, and their materials give them different properties, like how high they bounce.
We will learn that we choose a material to make an object depending on its properties and the purpose for which the object is to be used.
To understand this, we must first learn how to group, or classify, materials. Classification is simply the method of arranging objects or materials into groups based on their common properties. This is something we do all the time. In your kitchen, all the plates might be in one stack and all the glasses in another. A grocer keeps all the spices in one corner and all the pulses in another. This makes life organized and sensible.
Scientists do the same thing. We will learn to classify all the materials around us based on a few simple, observable properties.
This chapter is all about organizing our world, sorting a universe of different things into clear, logical groups. This very process of classification—of taking many different ideas and grouping them based on their properties—is the foundation of all science. It can be a lot to keep track of, but this is exactly what Teachoo is built for. We help you explore all these properties, from lustre to solubility, and organize them in a way that just makes sense. We are dedicated to helping you turn a long list of facts into clear, connected knowledge, so you can see the simple patterns that govern the world around you.
Here are the key properties we will investigate to become material detectives:
Appearance (Lustre) First, we will just look. How does the material appear? Does it shine?
Lustrous: We will call materials that have a shiny surface lustrous. These are usually metals like iron, copper, aluminium, and gold.
Non-Lustrous: Materials that are dull and do not have a shiny surface are non-lustrous, like paper, wood, and rubber.
Hardness vs. Softness Next, we will touch and press. How does the material feel?
Hard: Materials that are difficult to compress or scratch are called hard. A stone or a brick is a good example.
Soft: Materials that can be easily compressed or scratched are called soft, like a cotton pillow, an eraser, or a sponge.
Transparency (How we see through it) This is a big one. What happens when you try to look through the material? This property divides all materials into three important groups:
Transparent: These are materials that you can see through clearly. Light passes through them completely. Glass, air, and clean water are perfect examples.
Opaque: These are materials that you cannot see through at all. They block all light. Wood, a brick wall, and metals are all opaque.
Translucent: This is the in-between group. These are materials you can see through, but not clearly. Light gets scattered. Butter paper and frosted glass (the hazy glass on a bathroom door) are common examples.
Solubility (How it behaves in water) What happens when you mix the material with water?
Soluble: We will discover that some materials, like sugar and salt, completely disappear or dissolve in water. We call these soluble.
Insoluble: Other materials, like sand, chalk powder, and sawdust, do not mix with water, no matter how much you stir. We call these insoluble.
We will also see that this property applies to liquids (like oil, which is insoluble in water and forms a separate layer) and even gases (like oxygen, which is soluble in water and is what allows fish to breathe!).
Mass and Volume (The Universal Properties) After looking at all these properties that make materials different, we will end our investigation by asking: Is there anything that makes all materials the same?
The answer is yes. Every single material you can think of—from the air you breathe to the desk you are sitting at—shares two fundamental properties:
Mass: It "has stuff" in it (in common language, it has weight).
Volume: It takes up space. Your school bag, for example, takes up space on your seat, which is why you cannot sit on it at the same time!
This leads us to the biggest idea in the entire chapter: a general name for everything that has these two properties. We call it Matter.
Anything that occupies space and has mass is called matter.
This chapter teaches us to see the world in a new way. You will no longer just see a "bottle"; you will see "transparent glass" or "opaque plastic" and understand why it was chosen. You will no longer just see a "coin"; you will see a "lustrous metal." You will learn the basic language that scientists use to classify, organize, and understand the entire physical world.
To get started on this journey of exploration, click on any topic link to begin