# Introduction

Properties describe matter. A block of wood, milk, and air all have properties. All the material on earth is in three states-solid, liquid, and gas. The "state" of the matter refers to the group of matter with the same properties. In other words, you group the objects together according to their properties.

Solids
The wood block is solid. A solid has a certain size and shape. The wood block does not change size or shape. Other examples of solids are the computer, the desk, and the floor.

You can change the shape of solids.

Liquids
Milk is a liquid. Milk is liquid matter. It has a size or volume. Volume means it takes up space. But milk doesn't have a definite shape. It takes the shape of its container.

Liquids can flow, be poured, and spilled. Did you ever spill juice? Did you notice how the liquid goes everywhere and you have to hurry and wipe it up? The liquid is taking the shape of the floor and the floor is expansive limitless boundary (until it hits the wall). You can't spill a wooden block. You can drop it and it still has the same shape.

Gases
Do you notice how hard you are breathing? What you are breathing is oxygen? You need oxygen to live. That's why you can only hold your breath for a certain amount of time.

You can't see oxygen. It's invisible. It is a gas. A gas is matter that has no shape or size of its own. Gases have no color.

Gases are all around you. You can feel gas when the wind blows. The wind is moving air. Air is many gases mixed together.

In this chapter we are going to study intermolecular forces ,dispersion forces ,dipole -dipole forces etc