States of Matter

We know that everything around us is matter. The air we breathe, the food we eat and the water we drink, these are all considered to be made out ofmatter. But have you ever wondered what is the matter made of? To answer this question let us understand the kinetic particle theory.

Kinetic particle theory suggests that all matter is made up of extremely small particles called atoms or molecules. These particles are always in motion. The particles from which matter is made up of, have spaces between them. There are Forces of attraction between the particles. In different circumstances, these forces keep the particles bound together. As we know that there are three states of matter. These are solid, liquid and gas. Let us explore each state of matter based on the kinetic particle theory.

The particles in a solid are tightly packed. Due to this tight packing of the particles, the solids have fixed shape. An example of a solid is a grain of salt.The tight packing of the particles in a solid is due to presence of strong forces of attraction between them. The particles in a solid have very little freedom of movement. They only vibrate around their fixed position. Then why don’t we see a grain of salt vibrating? That is because these vibrations are very small and not visible to the eye.

The particles in a liquid do not have a regular arrangement like in solids. They are yet relatively near to each other. They can glide past each other. Liquids do not have a definite shape. Liquids take the shape of the container they occupy. For example, if we pour water in a glass, the water will take the shape of the glass.

Liquids have fixed volume. But what is volume when we talk about the three states matter? Volume is a measure of how much space something takes up. For example, 1 litre of water will remain 1 litre although you move it to another container. In liquids, the particles have more freedom of movement than in solids. They can move past one another. This is because of weaker forces of attraction between the particles of liquid as compared to solids.

A gas does not have a fixed shape. Instead, they take the shape of the container they are in. If you put a gas in a balloon, it fills the balloon and takes its shape. If you put a gas in a box, it takes the shape of the box. The particles in a gas don't stick to each other very strongly. They have weak forces of attraction between them. This is why gases can quickly spread out to fill their container. Some examples of gas are oxygen and carbon dioxide. Air is a mixture of different gas.

A gas does not have a fixed volume. This means you can compress a gas into a smaller volume. It is like squeezing a sponge to make it smaller. This happens because the gas particles have a lot of spaces between them.

Matter can be changed from one state to another by changing the arrangement of particles in it. For example, a solid can be changed into a liquid by a process called melting. Melting occurs when a solid is heated. As the solid gets warmer, its tiny particles start moving faster and faster because they get more energy. Eventually, they gain enough energy to break free from their fixed positions and begin sliding past one another. This change allows the solid to covert into a liquid. The specific temperature at which a solid is changed into a liquid is called the melting-point.

A liquid can be changed into a solid by a process called freezing. It occurs when the liquid loses heat, usually by getting colder. As the liquid cools down, its tiny particles slowdown and undergo loss of energy. Eventually, they undergo loss of energy enough to come together and form a regular, fixed pattern. This change converts a liquid into a solid. The specific temperature at which a liquid is converted into solid is called the freezing-point.

Boiling is the process in which a liquid substance changes into its gaseous state due to a rise in the temperature. When you heat up a liquid, its tiny particles start moving faster. As they move faster and faster, some particles gain enough energy to escape from the liquid and become a gas. These gas particles form bubbles that rise to the surface. The temperature at which a liquid is changed into a gas is called the boiling-point.

Condensation is the process in which a gas changes into a liquid. When a gas cools down, its tiny particles slowdown and come together. As the particles get closer, they form small liquid droplets. Can you tell why water droplets are formed on the outside of the ice cold glass of water? This is due to condensation.

When we heat a gas, the particles of gas gain energy. These high energy particles start moving at high speed. They start to collide with each other. As a result of this movement and collision, the volume of the gas increases. This is because particles are moving away from each other. They want to take up as much space as possible. We can say that the volume of a gas increases by increasing the temperature.

What happens if we decrease the temperature of a gas. If we decrease the temperature, the particles of gas will undergo loss of energy. As a result, the particles of gas will come closer to each other. In this way, the volume of gas decreases. Hence, we can say that the volume of gas decreases by decreasing the temperature.

Now let us understand the effect of pressure on the volume of a gas. Pressure is the force exerted per unit area on the surface of an object. In simpler terms, it is the push or squeeze applied to an area. When we increment the pressure on a gas, the particles of gas come closer to each other. The forces of attraction start to develop between them. As a result the volume of gas decreases. We can say that the volume of gas decreases by increasing the pressure.

When we decrease the pressure on a gas, the particles of gas will move away from each other. As a result the volume of gas increases. We can conclude that the volume of gas increases by decreasing the pressure.