1. Solids: Solids have a definite shape and volume and are characterised by strong intermolecular forces that hold the constituent particles (atoms, molecules, or ions) in fixed positions. Solids have a high density and low fluidity. Examples include ice, rock, and metal.
2. Liquids: Liquids have a definite volume but not a definite shape and can flow. The particles in liquids are still quite close together but not as rigidly held in place as in solids. Liquids have a higher fluidity than solids but a lower density. Examples include water, oil, and alcohol.
3. Gases: Gases have neither a definite shape nor a definite volume and can expand to fill any container. The particles in gases are very far apart and move freely with high energy. Gases have the lowest density and highest fluidity of the three basic states of matter. Examples include air, nitrogen, and helium.
4. Plasma: Plasma is a hot, highly ionised gas consisting of positively charged ions and negatively charged electrons that are separated from each other. It is often referred to as the "fourth state of matter" and is distinct from the other three because of its unique properties and behaviour. Plasma is commonly found in stars, including our sun, and can also be created artificially, for example, in fluorescent bulbs and plasma torches.
5. Bose-Einstein condensate (BEC): Bose-Einstein condensate is a state of matter that occurs when a gas of bosonic particles, such as atoms or molecules with an integer spin, is cooled to extremely low temperatures near absolute zero (-273.15 degrees Celsius). In this state, a large number of particles occupy the same quantum state, exhibiting coherent behaviour and exhibiting unique properties such as wave-like interference. BEC is a relatively recent discovery and an active area of research.
