what exactly is a quark?
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Any of a group of six elementary particles having electric charges of a magnitude one-third or two-thirds that of the electron, regarded as constituents of all hadrons.\n\n\nA soft creamy acid-cured cheese of central Europe made from whole milk.\n\n\nhypothetical truly fundamental particle in mesons and baryons; there are supposed to be six flavors of quarks (and their antiquarks), which come in pairs; each has an electric charge of +2/3 or -1/3 2: fresh unripened cheese of a smooth texture made from pasteurized milk, a starter, and rennet.
482088
That all matter is formed of particles, originally defined at atoms, then smaller and defined as neutrons, protons, and electrons, and now still smaller to quarks.
68836
Protons and neutrons are both made of quarks. A proton has two "up" quarks and one "down" quark, while the neutron has two "down" quarks and one "up" quark. (The up and down are just names for these two types of quark, there is no physical significance to the name. They could have selected Chocolate and Vanilla instead.)\n\nProtons and neutrons are almost always desribed as being composed of three quarks, but there are also gluons running around. Gluons are the particles which control the interaction of quarks within a proton or neutron. They carry the force that binds the three quarks together to form the larger particle.\n\nSo a proton or neutron has three quarks and a cloud of gluons.\n\nIf one combines a proton and an electron and a neutrino you will get a neutron, but, in the oddness of quantum physics that doesn't mean a neutron is made of these little guys.\n\nElectrons on the other hand seem to have no consituents, at least down to the level that has been probed with modern instruments.
474775
You would expect the sum of the rest masses of the quarks to be less than the mass of the proton or neutron.  A proton/neutron is a bound state of quarks made up of quarks and gluons.  With the gluons in there, you get more mass.  It has also been shown that the mass of a nucleus is greater than the mass of its constituent protons and neutrons.  This is because the "binding energy"  that is, the energy it takes to stick the nucleus together also adds to the mass of the nucleus.  \n\nSo, the quarks+gluons+binding energy=mass of proton/neutron\nYou can't really find out a velocity from that...
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Hi. One of the strangest is the 'pentaquark', a short lived particle made from five quarks. : http://www.answers.com/main/ntquery?s=pentaquark&gwp=16
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We dont know, but to the best of our knowledge, matter is composed of atoms composed of protons, neutrons, and electrons.  Protons and neutrons are composed of hadrons which are composed of quarks (electrons are quarks).\n\nQuarks may be composed of strings, which are 1 dimensional particles, but we cant really say.  Thats our best theory.\n\nSome people believe strings are the absolute smallest things out there.  In fact, at the 'size' of strings, distance and size dosent really make sense, so if they exist they are proably as small as anything else.  That is not to say that they are not composed of more fundamental things, whatever they might be.  It is to say that size dosent make much sense beyond strings, so they can be called the smallest.\n\nEnjoy.
146626
What exactly is that?
888560
a nucleus, containing protons and neutrons  and around that nucleus, there are electrons. [Although it more correct to speak of electron clouds, as they are not really localized. ]
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Quantum Physics is the Science and Study of Atomic Particles, the most basic of which is the Electron, the Proton and the Neutron, and the futher study of the constituent parts of those particles, Quarks, Muons, Gluons, etc etc etc.\n\nThe Standard Model is the best way to learn these particles. There is (apparently) no rhyme or reason as to the why's and wherefor's of the Standard Model - meaning that nobody knows WHY the weights are what they are, nobody knows why the numbers shake out the way they do and the particles organize themselves the way they do - this is one of the last great mysteries of Physics that modern M-Theory (String or SuperString Theory) is attempting to answer.\n\nHere's a good link or three\n\nOf them all, I would recommend the Wiki as a great place to start... Take notes, it's fairly complex, you can do it!
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Sensible colladers sometimes deliver quintessential yellow hazelnuts.  Improbably, lovely notebooks squash interconnected quark atmosphere lickers.  Trying to find me, instantly appear playing tank game please.
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This might not be one sentence, but might help in understanding the concept easily. \n\nOk...now...in simpler terms..\nWe all are familiar with an atom. Atom is made up of core nucleus and electrons around the nucleus. If you look inside the Nucleus, you will find protons and neurtons. If you further look inside protons and neutrons, you will have quazars. We were stuck there until the string theory came along. Now...Sting theory suggests that quazars has something inside and that is nothing but a vibrating string of energy(light), which gives it the structure. \n\nSo in sense, its like saying..we have different atoms because deep inside, the string of engery is vibrating with different nodes. Difference in string vibrations is what gives difference in structure of atoms from inside, which is translated outside. Its an interesting concept. \nBoth scientists and philosophers are equally interested in this because string theory says that it all boils down to the vibrations of strings of energy in the subatomic level. So that is like saying....matter might look solid but deep inside, its just energy...more like an invisible light. \nHope this explanation helps. Ofcourse there is more to it than what i explained. There is tons of mathematical calculations and revolutionary ideas in quantum physics that goes with string theory. They are still working on it. Try watching "The elegant universe". It was originally aired in PBS, but i guess you can buy it in bookstores like Barnes&Nobels. Its fantastic. You can understand it easily since they show animations of it.
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An atom is made up of electrons, protons and neutrons\n\nProtons are made of two Up and one Down Quarks. The neutron is made of two Down and one Up Quarks.\n\nProtons have a diameter of about 1.5×10−15 m\nNeutrons have a radius of about 0.8 × 10−15 m\nElectrons have a radius of about 3x10^-15 m\n\nQuarks must be smaller than 10^-18 m. This determination is based on the highest energy collisions currently available
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A photon, which is a quanta of evergy below which you cannot go-this is the smallest, and only, particle which carries radiant energy.  The photon is the energetic equivalent of the quark in matter.
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positively charged protons (in the nucleus), neutrally charged neutrons (also in the nucleus) and negatively charged electrons (which circle around the nucleus) ....also they have "discovered" other matter in the atom called quarks and a couple other similarly named items....but it is generally accepted that protons, neutrons, and electrons make up an atom....
1136639
In the Standard Model, quarks, electrons and the like are considered to be pointlike. This gives problems at short distances where for instance the electromagnetic force between two of them becomes infinite.\n\nThe basic idea of stringtheory is that the fundamental constituents of matter are strings of a length of order of 10^35 m which vibrate at specific frequencies. However, the simplest string theories give more problems then they solve and consistent theories requires more then four dimensions. \n\nMembranes take the idea even further.  The particles are represented by vibrating surfaces and higher dimensional objects.
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nothing what's the antimatter with you! seriously though if you mean antimatter, it's a form of matter in which most of it's properties are reversed.
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Protons and neutrons are the primary constituents of atomic nuclei, but these bits of matter can be further divided into quarks.  Quark come in six types, or "flavors:" up, down, strange, charm, top and bottom (or, if you prefer, truth and beauty.) Quarks are never observed by themselves, but are instead found in groups of two (mesons) or three (baryons). Nuclear particles are baryons -- neutrons are composed of two down quarks and an up quark (ddu), while protons are two up quarks and a down quark (uud).  The other four types of quarks are less stable, and tend to be observed only as components of high-energy, short-lived particles inside supercolliders, bubble chambers, and the like.\n\nProtons and neutrons are thus the only directly observable particles within the nucleus.  However, they are bound together by another type of particle, not directly detectable that appropriately enough is known as a gluon.  Gluons, like photons, are force-carrier particles, and they are the intermediary for the transmission of the weak nuclear force, which binds the positively charged protons and electrically neutral neutrons.