UNIT OVERVIEW

Have you ever wondered why ice melts on a hot day, why you can smell braai smoke from your neighbour's yard, or why a balloon expands when heated? The answers lie in understanding the three states of matter and the kinetic molecular theory — a model that explains how tiny particles behave in solids, liquids, and gases.

In this unit, you will discover the invisible world of particles in constant motion. You will learn to explain everyday observations using scientific principles and understand the energy changes that occur when substances change from one state to another.

By the end of this unit, you will be able to:

• Describe the three states of matter and their macroscopic properties
• Explain the kinetic molecular theory and its assumptions
• Use the kinetic molecular theory to explain the properties of solids, liquids, and gases
• Interpret heating and cooling curves
• Explain energy changes during changes of state
• Calculate energy requirements for phase changes

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