Matter (physics)
Matter, in the context of physics, is defined as any substance that possesses mass and occupies space, ultimately composed of molecules or atoms. Atoms, which are the fundamental units of matter, consist of subatomic particles including electrons, neutrons, and protons, which are further made up of elementary particles such as quarks and leptons. Matter can exist in several states, with the three most recognized being solid, liquid, and gas, alongside a fourth state known as plasma. The transition between these states occurs through phase changes, typically influenced by the addition or removal of energy in the form of heat.
In solids, matter maintains a rigid structure with tightly bound atoms or molecules, categorized into crystalline solids with regular geometric patterns, or amorphous solids, like glass, with irregular arrangements. Liquids, on the other hand, have a definite volume but take the shape of their containers, allowing atoms to move freely while remaining closely packed. Gases lack both definite shape and volume, expanding to fill any container due to the free movement of their widely spaced particles. Lastly, plasma is an ionized state of gas formed under high temperatures and pressures, containing charged particles that interact with electromagnetic forces. The study of matter is foundational to various scientific fields, including chemistry, engineering, and physics, illustrating its integral role in understanding the physical world.
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Matter (physics)
Matter is defined as any substance that has mass and occupies space (i.e., has volume). All physical objects consist of matter, which is ultimately made up of molecules or atoms; atoms are made up of subatomic particles such as electrons, neutrons, and protons; and these in turn are made up of elementary particles such as quarks and leptons. Matter can exist in various states or phases, the three best-known being liquid, gas, and solid; a fourth state of matter is plasma.
Overview
On Earth, most matter exists in three primary states: solid, liquid, and gas. When matter changes from one state to another, this process is referred to as a phase transition, and happens when energy in the form of heat is either added or taken away. In its solid state, matter has a rigid structure and resists changes to its size and shape. This rigid structure is due to the fact that the atoms or molecules that make up a solid are bound tightly together. Solids have two types of rigid structure. The first and more common is a regular geometric lattice structure, which is made up of a strong, repeatable pattern of crystals; solids with such a structure are known as crystalline solids. The second kind of solid structure has an irregular pattern, and is referred to as an amorphous solid; perhaps the most common example of this is glass. The categorization of a solid as either crystalline or amorphous depends on the material that makes up the solid and the conditions in which the object was formed. For example, a crystalline solid is usually formed through a slow cooling process, and amorphous solids are formed when a material is rapidly cooled.
A liquid is a state of matter that exists between the solid and gas states, and has definite volume but no definite shape, conforming to the container in which it is held. In the liquid state, the atoms or molecules of the substance are compressed as they would be in a solid state, but those atoms are free to move around.
A gas has neither definite shape nor definite volume, but rather expands to fill its container. Unlike a solid or liquid, individual gas particles are not bonded together, but spread far apart, suspended in space and moving freely. However, gases can be compressed, such as with compressed air or carbon dioxide in a can of soda. This can be achieved when increased pressure and decreased temperature are applied to the gas, which helps force it into a smaller space.
The last fundamental state of matter, plasma, is basically an ionized gas; it is created when a gas is heated at very high temperatures and pressures so that electrons are separated from the constituent atoms, making the substance a collection of positively charged particles and free electrons. Familiar forms of plasma found on Earth include fluorescent lights, neon signs, and the northern lights or aurora borealis. Although plasma is relatively uncommon on Earth, it is in fact the most common state of matter in the universe, as stars are made up of plasma. Like liquids and gases, plasma is fluid (meaning it flows and has an indefinite shape); however, because plasma contains charged particles, it readily responds to and generates electromagnetic forces.
Overall, matter exists in various forms all around us, and the study of matter is key to the scientific disciplines of chemistry, engineering, and physics.
Bibliography
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