What are the three main forms of matter?

The three main forms of matter are solid, liquid, and gas. Solids have a definite shape and volume due to closely packed particles, making them rigid and stable. Liquids have a definite volume but take the shape of their container because the particles are less tightly packed, allowing them to flow. Gases, on the other hand, neither have a definite shape nor a definite volume. The particles in a gas are spread out and can move freely, allowing gas to expand and fill any available space.

Understanding these fundamental states of matter is crucial as they underpin many principles in physics, chemistry, and other sciences that discuss the behavior of materials under various conditions. While plasma is another state of matter, it is not considered one of the main forms like solid, liquid, and gas. Ice and steam are specific manifestations of solid and liquid forms, respectively, but they do not represent distinct categories of matter.