What defines matter?

Matter is defined as anything that occupies space and has mass. This definition encompasses all physical substances in the universe, including solids, liquids, gases, and even plasma. By stating that matter occupies space, it implies that it has a volume, and when it has mass, it indicates that there is a measurable quantity of matter within that space. This fundamental understanding is crucial in various scientific fields, including physics and chemistry, as it helps to classify and differentiate various materials and their behaviors under different conditions.

While visibility and tangibility are characteristics of many forms of matter, not all matter can be seen or touched, such as gases or certain subatomic particles. Additionally, the classification of matter into solid, liquid, or gas reflects the physical states that matter can take, but does not encompass other crucial properties like mass. Lastly, heating or cooling matter relates to the energy state of the matter rather than its definition itself. Therefore, the idea that matter occupies space and has mass stands as the most comprehensive and accurate answer in defining what matter truly is.