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Lesson 9 of 10

7 min

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Here are the seven rules, in the exact words each lab uses.

Particulate Nature of Matter — what each lab checks
IdeaThe rule, as the lab applies it
Pieces too small to seeEvery substance is made of tiny particles. They are too small to see. A piece of chalk is a huge number of chalk particles.
Gaps between themThere are gaps between particles. These gaps are called interparticle spaces. Dissolved sugar goes into the gaps between water particles.
They never stop movingParticles never stop moving. They bump into each other and spread out. They spread faster when the water or air is warm.
Three arrangementsIn a solid, particles are packed close and held by strong pulls. In a liquid, they slide past each other. In a gas, they move freely in every direction.
Warming them upWarm a solid and its particles vibrate more. At the melting point, they leave their places. The solid becomes a liquid. At the boiling point, they move far apart. The liquid becomes a gas.
SqueezingPush a gas and its particles move closer. A gas has a lot of empty space between its particles. A liquid has very little, so water hardly squeezes.
What this picture explainsAsk three things. How close are the particles? How strong is the pull between them? How freely do they move?

Chalk is ground to a fine powder. What is each tiny speck?

  • A new substance
  • Still chalk
  • Nothing at all

Sugar is stirred into water and vanishes. The water tastes sweet. What does this show?

  • The sugar turned into water
  • The sugar was destroyed
  • The sugar broke into particles too small to see

Sugar is added to water. After stirring, the level is a bit lower than with undissolved sugar. Where did the sugar particles go?

  • Into the empty spaces between water particles
  • Into the glass
  • Into the air above

What fills the gaps between particles?

  • Air
  • Water
  • Nothing at all

A purple crystal is dropped into three glasses of water. One is hot, one is warm and one is ice cold. Which glass turns pink first?

  • The ice-cold glass
  • The hot glass
  • All three at the same time

Incense burns in one corner. After a while the whole room smells of it. Why?

  • Its particles keep moving and spread out
  • The smell stays in the corner
  • The room makes the smell on its own

How do particles in a solid differ from those in a liquid?

  • Solid particles are far apart
  • Liquid particles cannot move
  • Solid particles stay in place. Liquid particles slide past each other

Oil pours from a bottle. A steel spoon keeps its shape. Why?

  • Oil particles are held by strong pulls
  • Steel particles are held in place. Oil particles slide past each other
  • Steel has no particles

Table salt poured into a bowl takes the bowl's shape. Is it a liquid?

  • Yes, because it takes the shape of the bowl
  • No, each crystal is a solid
  • Yes, because it can be poured

A solid is warmed until it melts. What do its particles do at the melting point?

  • They stop moving
  • They disappear
  • They leave their places

A syringe is full of air. The tip is closed. You push the plunger in. What happens to the air particles?

  • They get smaller
  • They move closer together
  • They disappear

A syringe is full of water. The tip is closed. Why does the plunger hardly move?

  • Water is heavier than air
  • Water particles are already close together
  • Water has no particles

Every particle is taken out of a wooden stool. What is left?

  • A see-through stool
  • A stool that weighs nothing
  • Nothing

Chapter 7 of your NCERT book is Particulate Nature of Matter. Read it. Ask each time: how close, how strong a pull, how free?

Next: Nature of Matter: Elements, Compounds, and Mixtures.

Reveal every answer to finish this lesson.