📖 Lesson 2: Particulate Nature of Matter

👩🏽‍🏫 Introduction

Hey science explorer! 👋🏽

Have you ever wondered what everything is made of—from the air you breathe to the chair you’re sitting on? Even things that look solid and still are actually made of tiny, invisible particles constantly moving!

This lesson will help you understand the Particulate Nature of Matter—the idea that all matter is made of small, moving particles. Once you learn this, you’ll see the world differently. You’ll understand why ice melts, why we can smell food from far away, and how gases spread.

📘 Core Concepts

🔹 What is Matter?

Matter is anything that has mass and occupies space. Everything around you—solids, liquids, gases—is made of matter.

🔹 States of Matter

There are three main states:

• Solid – particles are packed tightly and vibrate in place (e.g. stone 🪨)

• Liquid – particles are close but can slide past each other (e.g. water 💧)

• Gas – particles move freely in all directions (e.g. air 🌬️)

🔹 Particle Theory of Matter

The Particle Theory helps us explain how matter behaves. Here are its main ideas:

🖼️ Diagrams

💡 Particle Arrangement in States of Matter:

Notice:

• Solids: tightly packed

• Liquids: loosely packed

• Gases: spread far apart

👩🏽‍🔬 Real-Life Examples

• Smell of food from the kitchen reaches your room → gas particles diffuse.

• Ice melting into water → particles gain energy and move more freely.

• Boiling water produces steam → liquid changes to gas as particles break apart.

🧩 Sample Problem Walkthrough

🧠 Problem:

Why do we see water droplets forming outside a cold soda bottle on a hot day?

✅ Step-by-Step Solution:

1. The air contains water vapor (gas).

2. The bottle is cold, so air around it cools.

3. Cooling makes gas particles slow down and stick together.

4. The gas turns into liquid—this is condensation.

✔️ Answer: The water droplets form because warm air condenses when it touches the cold bottle.

✍🏽 Practice Exercises

Exercise 1: Fill-in-the-Blanks

1. The three states of matter are ______, ______, and ______.

2. The particles in a solid are ______ packed and only ______ in place.

3. When a solid becomes a liquid, the process is called ______.

Answers:

1. solid, liquid, gas

2. tightly, vibrate

3. melting

Exercise 2: Multiple Choice

1. Which of the following has the weakest force of attraction between particles?
   A. Ice
   B. Water
   C. Steam
   D. Salt

✅ Answer: C. Steam

2. What happens to particles when a solid is heated?
   A. They stop moving
   B. They vibrate less
   C. They move faster
   D. They become bigger

✅ Answer: C. They move faster

Exercise 3: Match the Change to the State Transition

✅ Answers:

• Melting → B

• Condensation → A

• Evaporation → C

🌀 Recap

Today, we learned:

• Matter is made of particles that are always moving.

• The arrangement and energy of particles determine if matter is a solid, liquid, or gas.

• Changes in temperature affect how particles move, leading to changes of state.

• Real-life events like melting, boiling, and condensation can be explained using the Particle Theory.

💭 Reflection Prompt

Think about a time when you saw steam rising from hot food, or water droplets on a cold drink. Can you explain what happened based on particle behavior?

Write your explanation in your science journal or explain it aloud to a friend or classmate. Use words like particles, movement, state, and heat.