made of two protons and two neutrons
similar to an electron; positive charge
orbits nucleus; negative charge
bundle of energy; zero charge
found in nucleus; positive charge
very unstable; +, -, or zero charge
found in nucleus; zero charge
negative particle; negative charge
atomic energy converted to mass
answers:
positron
electron
meson
neutron
beta
proton
alpha
gamma
Answers
Answer:
Subatomic particle
physics
WRITTEN BY
Christine Sutton
Science writer. Research Associate, Department of Nuclear Physics, University of Oxford. Author of The Particle Connection and Spaceship Neutrino.
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ARTICLE CONTENTS
Subatomic particle, also called elementary particle, any of various self-contained units of matter or energy that are the fundamental constituents of all matter. Subatomic particles include electrons, the negatively charged, almost massless particles that nevertheless account for most of the size of the atom, and they include the heavier building blocks of the small but very dense nucleus of the atom, the positively charged protons and the electrically neutral neutrons. But these basic atomic components are by no means the only known subatomic particles. Protons and neutrons, for instance, are themselves made up of elementary particles called quarks, and the electron is only one member of a class of elementary particles that also includes the muon and the neutrino. More-unusual subatomic particles—such as the positron, the antimatter counterpart of the electron—have been detected and characterized in cosmic ray interactions in Earth’s atmosphere. The field of subatomic particles has expanded dramatically with the construction of powerful particle accelerators to study high-energy collisions of electrons, protons, and other particles with matter. As particles collide at high energy, the collision energy becomes available for the creation of subatomic particles such as mesons and hyperons. Finally, completing the revolution that began in the early 20th century with theories of the equivalence of matter and energy, the study of subatomic particles has been transformed by the discovery that the actions of forces are due to the exchange of “force” particles such as photons and gluons. More than 200 subatomic particles have been detected—most of them highly unstable, existing for less than a millionth of a second—as a result of collisions produced in cosmic ray reactions or particle accelerator experiments. Theoretical and experimental research in particle physics, the study of subatomic particles and their properties, has given scientists a clearer understanding of the nature of matter and energy and of the origin of the universe.
Large Hadron Collider
Large Hadron Collider
The Large Hadron Collider (LHC), the world's most powerful particle accelerator. At the LHC, located underground in Switzerland, physicists study subatomic particles.
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Subatomic particle
QUICK FACTS
KEY PEOPLE
Walther Bothe
Enrico Fermi
J.J. Thomson
Wolfgang Pauli
J. Robert Oppenheimer
Chen Ning Yang
Murray Gell-Mann
Donald A. Glaser
Martin Lewis Perl
Yukawa Hideki
RELATED TOPICS
Atom
Physical science
Particle accelerator
Quark
CP violation
Bose-Einstein condensate
Matter
Neutrino
Quantum chromodynamics
Symmetry
The current understanding of the state of particle physics is integrated within a conceptual framework known as the Standard Model. The Standard Model provides a classification scheme for all the known subatomic particles based on theoretical descriptions of the basic forces of matter.
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Basic Concepts Of Particle Physics
The divisible atom
See how John Dalton built his atomic theory on principles laid out by Henry Cavendish and Joseph-Louis Proust
See how John Dalton built his atomic theory on principles laid out by Henry Cavendish and Joseph-Louis Proust
John Dalton and the development of the atomic theory.
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The physical study of subatomic particles became possible only during the 20th century, with the development of increasingly sophisticated apparatuses to probe matter at scales of 10−15 metre and less (that is, at distances comparable to the diameter of the proton or neutron). Yet the basic philosophy of the subject now known as particle physics dates to at least 500 BCE, when the Greek philosopher Leucippus and his pupil Democritus put forward the notion that matter consists of invisibly small, indivisible particles, which they called atoms. For more than 2,000 years the idea of atoms lay largely neglected, while the opposing view that matter consists of four elements—earth, fire, air, and water—held sway. But by the beginning of the 19th century the atomic theory of matter had returned to favour, strengthened in particular by the work of John Dalton, an English chemist whose studies suggested that each chemical element consists of its own unique kind of atom. As such, Dalton’s atoms are still the atoms of modern physics. By the close of the century, however, the first indications began to emerge that atoms are not indivisible, as Leucippus and Democritus had imagined, but that they instead contain smaller particles.