Matter

For other uses, see Matter (disambiguation).

Hydrogen in its plasma state is the most abundant ordinary matter in the universe.

In classical physics and general chemistry, matter is any substance that has mass and takes up space by having volume.[1] All everyday objects that can be touched are ultimately composed of atoms, which are made up of interacting subatomic particles, and in everyday as well as scientific usage, matter generally includes atoms and anything made up of them, and any particles (or combination of particles) that act as if they have both rest mass and volume. However it does not include massless particles such as photons, or other energy phenomena or waves such as light or heat.[1]: 21 [2] Matter exists in various states (also known as phases). These include classical everyday phases such as solid, liquid, and gas – for example water exists as ice, liquid water, and gaseous steam – but other states are possible, including plasma, Bose–Einstein condensates, fermionic condensates, and quark–gluon plasma.[3]

Usually atoms can be imagined as a nucleus of protons and neutrons, and a surrounding "cloud" of orbiting electrons which "take up space".[4][5] However, this is only somewhat correct because subatomic particles and their properties are governed by their quantum nature, which means they do not act as everyday objects appear to act – they can act like waves as well as particles, and they do not have well-defined sizes or positions. In the Standard Model of particle physics, matter is not a fundamental concept because the elementary constituents of atoms are quantum entities which do not have an inherent "size" or "volume" in any everyday sense of the word. Due to the exclusion principle and other fundamental interactions, some "point particles" known as fermions (quarks, leptons), and many composites and atoms, are effectively forced to keep a distance from other particles under everyday conditions; this creates the property of matter which appears to us as matter taking up space.

For much of the history of the natural sciences, people have contemplated the exact nature of matter. The idea that matter was built of discrete building blocks, the so-called particulate theory of matter, appeared in both ancient Greece and ancient India.[6] Early philosophers who proposed the particulate theory of matter include the ancient Indian philosopher Kanada (c. 6th–century BCE or after),[7] pre-Socratic Greek philosopher Leucippus (~490 BCE), and pre-Socratic Greek philosopher Democritus (~470–380 BCE).[8]

  1. ^ a b R. Penrose (1991). "The mass of the classical vacuum". In S. Saunders; H.R. Brown (eds.). The Philosophy of Vacuum. Oxford University Press. pp. 21–26. ISBN 978-0-19-824449-3.
  2. ^ "Matter (physics)". McGraw-Hill's Access Science: Encyclopedia of Science and Technology Online. Archived from the original on 17 June 2011. Retrieved 24 May 2009.
  3. ^ "RHIC Scientists Serve Up "Perfect" Liquid" (Press release). Brookhaven National Laboratory. 18 April 2005. Retrieved 15 September 2009.
  4. ^ P. Davies (1992). The New Physics: A Synthesis. Cambridge University Press. p. 1. ISBN 978-0-521-43831-5.
  5. ^ Gerard't Hooft (1997). In search of the ultimate building blocks. Cambridge University Press. p. 6. ISBN 978-0-521-57883-7.
  6. ^ Bernard Pullman (2001). The Atom in the History of Human Thought. Oxford University Press. pp. 77–84. ISBN 978-0-19-515040-7.
  7. ^ Jeaneane D. Fowler (2002). Perspectives of reality: an introduction to the philosophy of Hinduism. Sussex Academic Press. pp. 99–115. ISBN 978-1-898723-93-6.
  8. ^ J. Olmsted; G.M. Williams (1996). Chemistry: The Molecular Science (2nd ed.). Jones & Bartlett. p. 40. ISBN 978-0-8151-8450-8.