This MCQ module is based on: Matter is Made of Particles
TOPIC 23 OF 50
Matter is Made of Particles
🎓 Class 8
Science
CBSE
Theory
Ch 7 — Conservation of Plants and Animals
⏱ ~28 min
🌐 Language: [gtranslate]
🧠 AI-Powered MCQ Assessment
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Myaischool Lt Science Assessment
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[myaischool_lt_science_assessment grade_level="class_8" science_domain="biology" difficulty="basic"]
Probe and Ponder
Pick up a fistful of dry sand. Let it trickle through your fingers — you can pile it in a little heap on the ground. Try the same with water from a glass. It slips away, spreading flat. Scoop some air in your empty palm — nothing visible, yet the breath you take in from it keeps you alive. Three very different behaviours. What makes them so different?
- Why can we stack stones or pile sand, but never stack water?
- Why does water take the shape of our folded hands, yet lose that shape the moment we release it?
- Why can we feel the weight of air on a weighing balance, but never see it?
- Is the very air you breathe today the same air people breathed thousands of years ago?
- Why does the smell of hot pakoras from the kitchen reach every room of the house?
All these riddles have one surprisingly simple answer — matter is made of incredibly tiny particles. By the end of this part, you will see that every solid, liquid and gas around you is really just countless invisible particles arranged in different ways.
7.1 What is Matter?
Look around. Your desk, the water in your bottle, the air you just exhaled, the clouds, the rocks, even you — everything is matter.
Matter: Anything that has mass and occupies space (has volume). Heat, light and sound are NOT matter — they carry energy but have neither mass nor volume.
Solids
Ice cubes, iron nails, wooden blocks, stones, sugar crystals.
Liquids
Water, milk, cooking oil, honey, juice, mercury.
Gases
Air, oxygen we breathe, LPG in cylinders, steam, helium in balloons.
7.2 Matter is Made of Particles
An Idea Older than 2500 Years
The notion that matter is built from tiny indivisible pieces is not new. Around 600 BCE, the Indian philosopher Maharishi Kanad proposed that if we kept breaking a substance into smaller and smaller pieces, we would eventually reach a piece so small it could not be broken further. He called it paramanu (the "smallest part"). Almost at the same time, the Greek thinker Democritus independently came up with a very similar idea, calling these pieces atomos — from which we get the modern word atom.
Today, science confirms their bold guess. Every piece of matter — this page, the air, a drop of water — is made of unimaginably small particles — atoms and molecules.
Evidence from the Kitchen and the Garden
How can we "see" something so tiny? We can't — but we can catch the particles red-handed through clever activities.
🔬 Activity 7.1 — The Disappearing SugarL3 Apply
🤔 Predict first: Take a glass filled exactly to a mark with water. Add 2 spoons of sugar and stir. What happens to the water level?
You need: a transparent glass, water, marker pen, sugar, spoon.
- Fill the glass with water up to a line marked on the outside.
- Add two level spoons of sugar and stir until fully dissolved.
- Check the water level at the mark.
Result: The sugar disappears, but the water level hardly changes!
Why? Water is not a solid sheet — there are tiny empty gaps between its particles. The sugar particles slip into those gaps, so the total volume barely grows. This is direct proof that particles have spaces between them.
Why? Water is not a solid sheet — there are tiny empty gaps between its particles. The sugar particles slip into those gaps, so the total volume barely grows. This is direct proof that particles have spaces between them.
🔬 Activity 7.2 — The Travelling FragranceL2 Understand
🤔 Predict first: Someone opens a bottle of perfume at one corner of the classroom. How soon will you — sitting on the other side — start smelling it?
- Stand at one end of a still room.
- A friend sprays a little perfume or peels an orange at the far end.
- Wait quietly. Notice when the smell reaches you.
Observation: Within seconds to a minute the fragrance reaches the whole room.
Why? Tiny perfume particles break away from the liquid, fly through the gaps between the moving air particles, and reach your nose. This spontaneous spreading of one substance into another is called diffusion.
Why? Tiny perfume particles break away from the liquid, fly through the gaps between the moving air particles, and reach your nose. This spontaneous spreading of one substance into another is called diffusion.
🔬 Activity 7.3 — A Purple Cloud in WaterL3 Apply
🤔 Predict first: If a single crystal of potassium permanganate is dropped into a glass of still water, will the colour stay in one spot or move?
- Take a tall glass of still, clear water.
- Gently drop one or two crystals of potassium permanganate at the bottom.
- Do not stir. Watch for a few minutes.
Result: A beautiful purple colour slowly rises and spreads through the water all on its own.
Why? The particles of the crystal dissolve into water and move between the gaps of water particles. Both types of particles are in motion — that is why the colour spreads even without stirring.
Why? The particles of the crystal dissolve into water and move between the gaps of water particles. Both types of particles are in motion — that is why the colour spreads even without stirring.
Four Pieces of Evidence that Matter is Particulate
Dissolving
Sugar vanishing in water shows particles slip into the gaps between water particles.
Smell spreads
Perfume or cooking aroma reaching every corner proves gas particles move freely.
Ink in water
A drop of ink colours the whole glass — diffusion works in liquids too.
Gas escaping
The whistle of a pressure cooker shows gas particles rushing out through the vent.
🎯 Why is it Possible? — Match the Scenario L3 Apply
Each scenario below can be explained by one idea about particles. Click the correct reason to test yourself.
1. Adding salt to a full glass of water does not cause the water to overflow.
Salt particles fit into the spaces between water particles. Salt makes water denser and it shrinks. Salt evaporates instantly.2. Incense stick smoke fills the whole puja room in minutes.
The walls push the smoke around. Particles of smoke and air are in constant motion and mix (diffusion). The smoke is magnetic.3. A drop of blue ink spreads throughout a beaker of water without stirring.
Water pulls colour from the drop. Ink particles and water particles are moving, so they mix on their own. Gravity pulls colour downward.📋 Competency-Based Questions
Ira is helping her grandmother make lemon sherbet. She fills a steel glass exactly to the top with water, then stirs in two spoons of sugar and a pinch of salt. To her surprise, nothing spills. Meanwhile, her little brother, sitting three rooms away, asks, "Didi, are you making sherbet? I can smell the lemon!"
Q1. L1 Remember Name any two Indian and non-Indian thinkers who first suggested that matter is made of tiny indivisible particles.
Answer: The Indian sage Maharishi Kanad (who called them paramanu) and the Greek philosopher Democritus (who called them atomos).
Q2. L2 Understand Why did the water in Ira's glass not spill even after dissolving sugar and salt?
Answer: C. There are empty spaces between water particles, and the dissolved particles fit into them — so the total volume barely changes.
Q3. L3 Apply Her brother smells lemon three rooms away. Explain using the idea of particles.
Answer: Tiny particles of the lemon's fragrance escape into the air and are in constant motion. They travel through the gaps between air particles, spread across the house (diffusion), and finally reach his nose.
Q4. L4 Analyse Give two everyday observations (other than sugar in water) that prove matter is made of particles.
Answer: (i) Ink spreading on its own in a glass of water (diffusion in liquid). (ii) Smell of hot food travelling across the house (diffusion in gas). (Other valid answers: steam escaping from a cooker, potassium permanganate colouring water, agarbatti smoke filling a room.)
Q5. L5 Evaluate A friend argues: "Water is a continuous fluid — it has no particles or gaps, otherwise we could see through them." Judge this statement.
The statement is incorrect. The gaps between water particles are far smaller than the wavelength of light, so we cannot see them — yet we can prove they exist. When sugar dissolves without raising the water level, and when ink spreads in water, both events are only possible because of those spaces and because the particles themselves move.
🔗 Assertion–Reason Questions
Assertion (A): When sugar is added to a filled glass of water, the water does not overflow.
Reason (R): There are empty spaces between water particles into which sugar particles can fit.
Answer: A. The activity directly demonstrates that particles of matter have gaps between them.
Assertion (A): A bottle of perfume opened at one end of the room is smelt at the other end.
Reason (R): Perfume is a very heavy liquid that sinks to the floor.
Answer: C. A is true but R is wrong — smell spreads because particles of perfume vaporise and move (diffuse) through the air, not because the liquid is heavy.
Assertion (A): Maharishi Kanad is credited with one of the earliest atomic ideas in human history.
Reason (R): He suggested that matter, if divided again and again, finally reaches an indivisible particle called paramanu.
Answer: A. Kanad's idea of paramanu is precisely what makes his thinking an early atomic theory.
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