By: Kashish Shibbu

States Of Matter

What is matter ???

Matter is the stuff that things are made from. The three most common states are solid, liquid, and gas. There is also a fourth state of matter called plasma, but it is only found in special situations, such the centre of stars .

Plasma

Solids

A solid has a definite shape and usually cannot be compressed. Solids tend to stay in the same place and do not flow like liquids or gases. They have a variety of properties. Some are hard and strong, others are quite flexible. Some, such as metals, conduct electricity, others are non-conductor. Some are very heavy for their volume others are quite light. Common solids include gold, ice and plastics.

LIQUIDS

Liquids do not have have definite shapes. They are fluids – that is, they are a substance that can be poured into different sized and shaped containers. We say they can flow. Like solids, liquids cannot be compressed. They are quite dense, but usually less dense than solids.

Gases

Gases are very easy to compress. They fill up the entire volume of the space they are in. Like liquids they also can flow easily. They have very low density, much lower than liquids.

Plasma

Plasma is a very complex state of matter. More that 99 % of what we can see is plasma. As material is heated from solid to liquid to gas, and then even hotter, it begins to change the properties within the particle itself. When these properties change, we have have the fourth state : plasma. We use plasma in everyday life. For example, it is produced inside the glass tubing of neon advertising signs and plasma televisions.

Moving particle theory

The word ‘kinetic’ relates to the idea of movement.

Kinetic theory can be used to explain the properties of solids, liquids and gases. The moving particle theory suggests that all material is made of extremely small moving particles. In general, particles move fastest in gases. When we heat up a substance, what we really are doing is making the particles faster.

Particles inside a solid

The particles in a solid are all close together. They are also more or less fixed in their positions. They don’t move too far away from this position because they are strongly attracted to nearby particles. This is why solids have a fixed shape.

Particles inside a liquid

When energy is give to a solid, the particles vibrate more. They move farther away from the average central position and from one another. Attractions between particles become weakened, so the particles can move around more. The solid becomes a liquid.

Particle inside a gas

When energy is given to a liquid, again the particles begin to move around more. The particles move around faster until the attractions between them is not strong enough to hold them together. They escape the liquid to become a gas. They can now move very far apart from one another. The particles can move quickly to any part of the container.

We all know ice melts if it is left in the sunshine. This melting is called change of state. The state of a substance depends on the environment that surrounds and affects it. What we know as natural gas on Earth is a solid at a normal temperature and pressure. In one sense, a gold ring is just ‘frozen’ gold. Heat gold up and it turns into a liquid that can be poured into moulds to make jewellery and gold nuggets.

Change Of State

Melting and boiling points

Melting points

The melting point is the temperature at which a solid changes into a liquid.

Heating up a solid will cause particles to vibrate faster.

At certain temperature, the particles have energy to break away from their solid positions and turn into liquid.

Boiling point

The boiling point is the temperature at which a liquid change to a gas.

The particles have enough energy to break away from liquid and turn into gases.

Example : Water boils at 100 degree Celsius

Evaporation

When liquids are heated above their boiling points they turn into gases and this process is called evaporation.

Evaporation takes energy from surroundings and causes cooling,

eg: acetone or alcohol evaporating on our hand,

clothes getting dry by evaporation.

Condensation

The process in which water vapour condenses to form liquid water is called condensation.

Condensation is the opposite of evaporation

The stages of condensation are Evaporation Gas Condensation

liquid.