# Chapter 1: The Particulate Model of Matter

Everything around us is matter, but what exactly is matter made up of?? Now I know. It's made up tiny particles, which are arranged in a pattern and are constantly moving about. The particles in each state of matter are arranged differently and move at different speeds.

Solid
Particles are packed tightly together due to the strong attraction among one another. This results in solids not being able to be compressed. The particles are arranged in a fixed, regular pattern, which explains why solids have a fixed shape and volume. As the solids are packed very closely together, there's not much room for movement, hence the particles can only vibrate about their fixed positions.
Liquid
Particles are attracted to one another, therefore they are packed closely together. As a result, liquids cannot be compressed. The particles are not arranged in a fixed pattern, thus the particles are able to slide past one another and move over short distances, which explains why liquids do not have a fixed shape.
Gas
Particles are weakly attracted to one another, thus they are far apart from one another. Due to the huge space between the particles, gases can be compressed easily. The particles also travel at high speeds in random directions, which means they are free to occupy any available space. This explains why a gas has no fixed shape or volume.

The Particulate Model of Matter helps to explain the changes in states of matter. The different changes are: Melting, Freezing, Boiling, Condensation and Sublimation. For melting and boiling, the particles are strongly heated. This causes the particles to gain energy and thus, move at a faster speed. Once they have possessed sufficient energy (meaning they have reaching the melting/boiling point) the particles then overcome the forces of attraction, thus breaking free from one another. As for freezing and condensation, heat is removed from the particles, and the particles gradually lose energy, hence moving less rapidly. As the temperature continues to drop, the particles lose more energy till they are close enough to be attracted to one another.

Sublimation is a unique process whereby a solid turns into a gas directly, passing the liquid state entirely. One such example of sublimation is dry ice. In terms of the particulate model of matter, the original arrangement of the particles in the solid state is a fixed pattern, with the particles packed tightly due to the strong attraction between them and vibrating about their fixed position. As heat is applied, the particles begin to gain energy and vibrate about their fixed positions vigorously. As the temperature continues to increase, the particles move even more rapidly, till the point where they have possessed enough kinetic energy to overcome the forces of attraction, they break free from one another and spread out far apart from one another, moving at high speeds in all directions. The solid has turned into a gas.

For this topic, I also learnt about the heating and cooling curves. The temperature starts rising from below zero degree Celsius, as the melting point of solids is zero. As the temperature increases, the particles gain energy and begin to vibrate more rapidly. As the temperature continues to rise, the particles begin to vibrate even more vigorously till it reaches the melting point of solids. The heat supplied is used to overcome the forces of attraction between the particles, hence the temperature doesn't rise but remain constant. In this phase of changing from a solid to a liquid, there is the same amount of solid particles and liquid particles.
Once all the particles have broken free, the temperature continues to rise. The liquid particles, now in clusters, gain energy and move about rapidly till it reaches the boiling point of liquids (100 degree Celsius). Here, the temperature remains constant once more as the supplied heat is used to overcome the forces of attraction between the liquid particles. The liquid particles begin to break free from one another and form gas particles. The amount of liquid particles and gas particles is about the same. Once all the liquid particles have broken free, the particles are now spaced far apart from one another due to the weak attraction between them and move at high speeds in different directions.

I see...
-that the 3 states of matter are related as they change from one form to another each time heat is applied due to the different arrangements of the particles.
-when heat is applied, the particles are arranged differently, spreading further apart in each state.
-when heat is lost, the particles' movement is less hectic.
I think...
-with the particulate model of matter, the processes of melting, condensation, boiling and freezing can be better understood.
-the different states of matter is now easier to understand, as we know why some matter can be compressed whereas why others can't.
-one is able to explain daily life situations, such as the melting of ice in a drink, with the Particulate Model of Matter
I wonder...
-what will happen if the particles cease moving.
-why do particles have to be in constant motion.