What defines the three states of matter: solid, liquid, and gas?

The three states of matter: solid, liquid, and gas, are defined by their particle arrangement, energy, and movement.

In more detail, the state of matter is determined by the physical properties of a substance, which are influenced by the arrangement and movement of its particles, as well as the energy they possess.

In a solid state, particles are tightly packed together in a fixed, regular pattern. They vibrate around a fixed point but do not move from place to place. This gives solids a definite shape and volume. The energy of the particles is relatively low, as they are not free to move around.

In a liquid state, particles are close together but not in a fixed arrangement. They can move around each other, which allows liquids to flow and take the shape of their container, although they still have a definite volume. The energy of the particles is higher than in solids, as they have more freedom to move.

In a gas state, particles are far apart and in random arrangement. They move quickly in all directions, which allows gases to fill their container completely, taking both the shape and volume of their container. The energy of the particles is the highest among the three states, as they are free to move anywhere.

The state of a substance can change through heating or cooling, which alters the energy of the particles. For example, heating a solid can give the particles enough energy to overcome the forces holding them in place, causing the solid to melt into a liquid. Similarly, heating a liquid can give the particles enough energy to break free completely, causing the liquid to evaporate into a gas. Conversely, cooling a gas or a liquid can decrease the energy of the particles, causing them to come closer together and condense into a liquid or solidify into a solid, respectively.