States of matter

Introduction to matter

Everything you see around you is matter. The water you drink, the air from your fan, and the table you use in school are all matter. Matter is anything that has weight and takes up space.

It means that if something can be weighed on a scale and can fill a container, it is matter.

The three main states of matter

In your daily life, you see matter in three forms: solids, liquids, and gases. Think of an ice block, liquid water, and the steam coming out of a boiling kettle. They are all the same water but in different states.

Solid state

Solids are hard and have a fixed shape. If you put a stone inside a bowl, it stays a stone. The particles are packed very tightly together like students sitting closely in a crowded bus. They cannot move around; they only vibrate.

This means a solid will not change its shape unless you break it or melt it.

Liquid state

Liquids can flow. If you pour palm oil from a bottle into a plate, it takes the shape of the plate. The particles are close but have small spaces to move past each other. This is why you can pour water.

This means that one liter of fuel will always be one liter, even if you move it from a gallon to a drum.

Gaseous state

Gases are all around us but often invisible, like the air we breathe. Gas particles are very far apart and move very fast in all directions. They fill up any space they find, like the smell of soup moving from the kitchen to the parlor.

This means a small amount of cooking gas can expand to fill a whole room if the cylinder leaks.

Comparison of states

To understand the difference, look at how they pack themselves:

Solids: Particles are very close, highly ordered, and held by strong forces.

Liquids: Particles are slightly apart, disordered, and can slide over each other.

Gases: Particles are very far apart, move randomly, and have very weak forces between them.

Standard temperature and pressure

In Chemistry, we measure matter at Standard Temperature and Pressure (S.T.P). This allows scientists to compare results everywhere. Standard temperature is 273 K (0 degrees Celsius) and standard pressure is 760 mmHg or 1.01 x 10⁵ N m^-2.