Apna Gyaan

Author: Naivedya Moondra

What is Matter?

As we all know, the matter is anything that has mass and occupies space. So, almost everything we see around us is matter. For example- Air, Water, A table et cetera. But many things do not have a physical appearance. Such things are not considered the matter. For example- Our thoughts, Fear, Anger et cetera.

Physical Properties of Matter:

• The matter is made up of particles. These particles are called molecules. These molecules are very small, even smaller than what we can see with our naked eye.
• Molecules/Particles of matter have spaces between them. This space is called intermolecular space.
• Molecules of matter are continuously moving, i.e. they possess kinetic energy.
• Molecules of matter attract each other. This force of attraction between molecules is called the intermolecular force of attraction.

States of Matter:

Based on their physical properties, matter is divided into three states:

Solids:

We all know what solids are. For this reason, I will not explain this topic in-depth. Let’s move to the properties of solids…

Properties of solids:

Here are some properties of solids you may not have heard of :

• Molecules of solids are tightly packed, i.e. they have high density.
• They are rigid, i.e. they are negligible compressibility.
• They have fixed volumes that cannot be altered.

Liquids:

Properties of Liquids:

Here are some uncommon properties of liquids:

• Molecules of liquids are loosely packed, i.e. they have a relatively lower density than solids.
• They aren’t rigid and can be slightly compressed.
• They can change shape and thus are called fluid.

Gases:

Properties of Gases:

Behold! Properties of gases coming up…

• Molecules of gases are extremely loose, i.e. have a very, very low density.
• They are highly compressible.
• They can change shape and thus are called fluid.

Solid VS Liquid VS Gas:

Conversion of States of Matter:

You all know what these processes are, and I don’t need to explain them.

Latent Heat:

Now, I was going through the textbook and this concept “latent heat” was explained very abstractly. I will now try to make you understand this concept.

• Latent means “hidden”. So, latent heat refers to the heat which gets absorbed by a substance without a rise in temperature.
• This is the heat required for phase change.
• This means that at 0^oC, if we supply heat to ice until it converts to water, there will be no change in temperature.

Effect of Change in Pressure:

• Applying pressure and reducing temperature can liquefy gases.
• This is because when we apply pressure and reduce temperature, we bring the molecules of the gas closer together and eventually it becomes a liquid.
• Ex- LPG, CNG et cetera.

Evaporation:

Evaporation is the process of conversion of a liquid into a gas below its boiling point. This is a surface phenomenon, i.e., it occurs only on the surface of the liquid and not the whole liquid.

Factors Affecting Evaporation:

There are many factors which affect the rate of evaporation. They are:

• Temperature: With an increase in temperature, the rate of evaporation increases.
• Surface Area: As I have stated before, evaporation is a surface phenomenon. This means that if the surface area is increased, the rate of evaporation increases.
• Humidity: The air can only hold a certain amount of water at a time. This means that with an increase in humidity, the rate of evaporation decreases.
• Wind Speed: With an increase in wind speed, the rate of evaporation increases.

How does Evaporation cause Cooling?

This is one of the easiest topics in this chapter once you understand it. So, evaporation causes cooling. I will explain why this happens in the following paragraph.

For evaporation to occur, we need a higher temperature/energy. Thus, when evaporation occurs, the liquid getting evaporated loses energy, resulting in a decrease of energy/temperature of the liquid. The particles of liquid absorb energy from the surroundings to regain the energy lost during evaporation. So, this is the reason why evaporation causes cooling. This is seen in earthen pots and desert coolers.

Other States of Matter:

Other than solids, liquids, and gases, there are two other states of matter. They are:

• Plasma: This state is nothing but super excited and super energetic gas particles. This is the most abundant state of matter in the universe.
• Bose-Einstein Condensate (BEC): This is the exact opposite of Plasma. So, it consists of a gas-cooled to a temperature near or on absolute zero ( 0K or -273^oC).

Thus ends the chapter “Matter in Our Surroundings”. Thank you.