🔬 Class 8 Science – Particulate Nature of Matter Original Visual Revision Notes
Aligned with NCERT Class 8 Science (Curiosity 2024). Independently created study material. Not affiliated with or endorsed by NCERT.
🌐 Real-World Connection: Drop a single cube of sugar into a glass of water. Stir it, and soon the sweetness spreads throughout the entire glass — even reaching the very bottom without you touching it there. How? Because all matter is made of incredibly tiny particles that are always moving, always spreading, and always filling every available space. These particles are so small that you cannot see them, yet they explain everything: why perfume fills a room, why ice melts, why clothes dry, and why steam condenses on a cold mirror.
🔬 Topic 1: Matter is Made of Tiny Particles
Everything is made of tiny particles.
We cannot see these particles.
They are very, very small.
A drop of ink has millions of particles.
Particles make up all things.
🔀 Topic 2: Particles are Always Moving
Particles never stop moving.
They move in all directions.
Hot things have faster particles.
Cold things have slower particles.
This movement is called Brownian motion.
🔧 Topic 3: Particles Have Spaces Between Them
Particles have gaps between them.
In solids, gaps are very small.
In liquids, gaps are bigger.
In gases, gaps are very big.
Sugar dissolves because of these gaps.
🌡 Topic 4: Three States of Matter
Matter has three states.
They are solid, liquid, gas.
Ice is a solid.
Water is a liquid.
Steam is a gas.
🧱 Topic 5: Properties of Solids
Solids have a fixed shape.
Solids have a fixed volume.
Particles are packed tight.
Particles can only vibrate.
Examples: stone, book, ice.
💧 Topic 6: Properties of Liquids
Liquids have no fixed shape.
Liquids have a fixed volume.
They take the shape of container.
Particles can slide over each other.
Examples: water, milk, oil.
🌀 Topic 7: Properties of Gases
Gases have no fixed shape.
Gases have no fixed volume.
They fill the whole container.
Particles move very fast.
Examples: air, oxygen, steam.
🔥 Topic 8: Change of State
Heat can change the state.
Melting: solid becomes liquid.
Boiling: liquid becomes gas.
Condensation: gas becomes liquid.
Freezing: liquid becomes solid.
💦 Topic 9: Evaporation
Evaporation happens at any temperature.
Only surface particles escape.
It is a slow process.
Wet clothes dry by evaporation.
Evaporation causes cooling.
☀ Topic 10: Factors Affecting Evaporation
More heat = faster evaporation.
More surface area = faster drying.
Wind helps evaporation happen faster.
Humid air slows evaporation down.
Spread clothes wide to dry faster.
🎨 Section 2 — Easy Illustrations
Hover over elements to explore. Diagrams animate as you scroll.
Fig 1: How particles are arranged in solid, liquid, and gas.
Fig 2: How matter changes state. Add heat or remove heat.
Fig 3: Surface particles leave the liquid. This is evaporation.
Fig 4: Four things that change evaporation speed.
Fig 5: Ink particles spread in water because particles are always moving.
✏️ Section 3 — Worked Examples
🔶 Example 1: Identify the State
A thing has no fixed shape and fixed volume. What state is it?
1Check shape: No fixed shape
2Check volume: Fixed volume
3No fixed shape + fixed volume = liquid.
✔ Answer: It is a liquid.
🔶 Example 2: Why Does Ice Melt?
You keep ice in the sun. What happens?
1Sun gives heat to the ice.
2Particles move faster.
3Solid changes to liquid. This is melting.
✔ Answer: Ice melts and becomes water.
🔶 Example 3: Fast or Slow Evaporation?
A wet towel is spread flat on a windy hot day. Will it dry fast or slow?
1Spread flat = large surface area.
2Windy = wind helps evaporation.
3Hot = more heat = faster.
✔ Answer: It will dry very fast.
📋 Section 4 — Cheat Sheet
Word
Meaning
Matter
Anything that has mass and takes space
Particle
A very tiny piece of matter
Solid
Fixed shape and fixed volume
Liquid
No fixed shape but fixed volume
Gas
No fixed shape and no fixed volume
Melting
Solid becomes a liquid (add heat)
Boiling
Liquid becomes a gas (add more heat)
Condensation
Gas becomes a liquid (remove heat)
Freezing
Liquid becomes a solid (remove heat)
Evaporation
Liquid slowly becomes gas at the surface
Diffusion
Particles mix on their own
Brownian motion
Random zig-zag movement of tiny particles
🏠 Section 5 — Take-Home Handout
Part A — Fill in the Blanks
1. Everything is made of tiny __________.
2. Solids have a __________ shape.
3. Liquids take the shape of the __________.
4. When ice melts, it becomes __________.
5. Evaporation causes __________.
Part B — True or False
1. Gas particles are very close together. ( )
2. Melting means solid becomes liquid. ( )
3. Wind slows down evaporation. ( )
4. Particles in a solid can only vibrate. ( )
5. Condensation means gas becomes liquid. ( )
Part C — Short Answer
1. Name the three states of matter.
2. Why do wet clothes dry faster in wind?
3. What happens when you heat water to 100 degrees?
Part D — Match the Columns
Column A
Column B
1. Melting
a. Gas to liquid
2. Boiling
b. Solid to liquid
3. Condensation
c. Liquid to solid
4. Freezing
d. Liquid to gas
5. Evaporation
e. Slow liquid to gas at surface
Part E — Draw and Label
Draw particles in a solid, a liquid, and a gas. Show the spaces between them.
✅ Detailed Solutions — Section 5
Part A: Fill in the Blanks
Everything is made of tiny particles.
Solids have a fixed shape.
Liquids take the shape of the container.
When ice melts, it becomes water (liquid).
Evaporation causes cooling.
Part B: True or False
False — Gas particles are very far apart from each other, not close together. That is why gases have no fixed shape or volume.
True — Melting is the process by which heat causes a solid to become a liquid. Example: ice melting into water.
False — Wind speeds up evaporation by carrying away the evaporated particles from the surface, allowing more to escape.
True — Particles in a solid are packed tightly together and can only vibrate in place; they cannot move freely.
True — Condensation is the process by which a gas cools down and becomes a liquid. Example: steam becoming water droplets on a cold mirror.
Part C: Short Answer
The three states of matter are: Solid, Liquid, and Gas.
Wet clothes dry faster in wind because wind carries away the water vapour (evaporated particles) from the surface of the cloth. This makes room for more particles to evaporate, so evaporation continues faster instead of slowing down when the air near the cloth gets saturated.
When water is heated to 100°C, it boils and turns into steam (gas). The particles gain enough energy to escape from the surface rapidly — this is called boiling.
Part D: Match the Columns
Melting → b. Solid to liquid
Boiling → d. Liquid to gas
Condensation → a. Gas to liquid
Freezing → c. Liquid to solid
Evaporation → e. Slow liquid to gas at surface
Part E: Draw and Label
Draw three boxes side by side. In each box, draw circles representing particles:
Solid: Draw circles packed tightly in neat rows with very small gaps. Label: "Fixed shape, Fixed volume, Particles vibrate only."
Liquid: Draw circles loosely arranged with small irregular gaps, touching but not in neat rows. Label: "No fixed shape, Fixed volume, Particles slide."
Gas: Draw only a few circles spread far apart with large empty spaces between them. Label: "No fixed shape, No fixed volume, Particles move fast."
🃏 Section 6 — Revision Flashcards
What is matter made of?
Matter is made of very tiny particles.
Name the three states of matter.
Solid, Liquid, and Gas.
What is melting?
When a solid becomes a liquid by heating.
What is condensation?
When a gas cools and becomes a liquid.
What is evaporation?
Liquid slowly turns to gas at the surface.
Does evaporation cause heating or cooling?
Evaporation causes cooling.
What makes evaporation faster?
More heat, wind, large surface, dry air.
Why does ink spread in water?
Because particles keep moving and mix. This is diffusion.
🧠 Section 7 — Mind Map
Mind Map: 8 key ideas of Particulate Nature of Matter.