what are neutrons made of ?

Answer 1

One up and 2 down quarks, according to the current quantum chromodynamic theory.

Answer 2

I'll try and clarify what other people have been saying for a non-physicist.

Basically, current theory suggests that there are these 'ultramicroscopic' (really REALLY tiny) particles called quarks, which come in a variety of flavours, but the two we are concerned with are up quarks and down quarks.

An up quark carries a charge of 2/3, while a down quark carries one of -1/3. Thus 2 up quarks and 1 down quark will make a +1 charge (a proton) and 1 up quark nad 2 down quarks make a 0 charge (neutron). Electrons are not made of quarks.

The quarks are held together by a force called the 'strong force'. This is a bit like gravity, except it only works on very small scales, so you only notice it in this situation.

What quarks are made of is another speculation, but the most popular theory (string theory) is that they are made up of tiny vibrating strings. It sounds bizarre, and is, but believe it or not, it helps solve a lot of issues. If you want to find out more, read 'the elegant universe' by Brian Greene. It's not a chunky textbook, it's rather a really easy to read explanation of string theory.

Hope this helps!

Answer 3

A neutron is made of one up quark and two down quarks. These quarks are held together by gluons. The quarks and the gluons are just zero-dimensional strings with a vibrational pattern that corresponds to their properties as up quarks, down quarks, and gluons. The strings are just vibrating strands of pure energy that are held down to a membrane, unless, of course, they are gravitons.

Answer 4

read up about neutrons

http://www.historyoftheuniverse.com/neutron.html


Pointer Sisters sang a song- doing the neutron dance
http://www.youtube.com/watch?v=GUb0ohyIu_c

Answer 5

Neutrons are uncharged particles found within atomic nuclei. Neutrons were discovered by James Chadwick in 1932.

In physics, the neutron is a subatomic particle with no net electric charge and a mass of 939.573 MeV/c² (1.6749 × 10-27 kg, slightly more than a proton). Its spin is ½. Its antiparticle is called the antineutron. The neutron, along with the proton, is a nucleon.

Stability
Outside the nucleus, free neutrons are unstable and have a mean lifetime of 885.7±0.8 seconds (about 15 minutes), decaying by emitting an electron and antineutrino to become a proton:

This decay mode, known as beta decay, can also occur within certain unstable nuclei. Particles inside the nucleus are typically resonances between neutrons and protons, which transform into one another by the emission and absorption of pions.

Interactions
The neutron interacts through all four fundamental interactions: the electromagnetism, weak nuclear, strong nuclear and gravitational interactions.

Although the neutron has zero net charge, it may interact electromagnetically in two ways: first, the neutron has a magnetic moment of the same order as the proton; second, it is composed of electrically charged quarks. Thus, the electromagnetic interaction is primarily important to the neutron in deep inelastic scattering and in magnetic interactions.

The neutron experiences the weak interaction through beta decay into a proton, electron and electron antineutrino. It experiences the gravitational force as does any energetic body; however, gravity is so weak that it may be neglected in most particle physics experiments.

The most important force to neutrons is the strong interaction. This interaction is responsible for the binding of the neutron's three quarks (one up quark, two down quarks) into a single particle. The residual strong force is also responsible for the binding of nuclei: the nuclear force. The nuclear force plays the leading role when neutrons pass through matter. Unlike charged particles or photons, the neutron cannot lose energy by ionizing atoms. Rather, the neutron goes on its way unchecked until it makes a head-on collision with an atomic nucleus. For this reason, neutron radiation is extremely penetrating and dangerous.

Detection
Main article: neutron detection
The common means of detecting a charged particle by looking for a track of ionization (such as in a cloud chamber) does not work for neutrons directly. Neutrons that elastically scatter off atoms can create an ionization track that is detectable, but the experiments are not as simple to carry out; other means for detecting neutrons, consisting of allowing them to interact with atomic nuclei, are more commonly used.

A common method for detecting neutrons involves converting the energy released from such reactions into electrical signals. The nuclides 3He, 6Li, 10B, 233U, 235U, 237Np and 239Pu are useful for this purpose. A good discussion on neutron detection is found in chapter 14 of the book Radiation Detection and Measurement by Glenn F. Knoll (John Wiley & Sons, 1979).

Uses
The neutron plays an important role in many nuclear reactions. For example, neutron capture often results in neutron activation, inducing radioactivity. In particular, knowledge of neutrons and their behavior has been important in the development of nuclear reactors and nuclear weapons.

Cold, thermal and hot neutron radiation is commonly employed in neutron scattering facilities, where the radiation is used in a similar way one uses X-rays for the analysis of condensed matter. Neutrons are complementary to the latter in terms of atomic contrasts by different scattering cross sections; sensitivity to magnetism; energy range for inelastic neutron spectroscopy; and deep penetration into matter.

The development of "neutron lenses" based on total internal reflection within hollow glass capillary tubes or by reflection from dimpled aluminum plates has driven ongoing research into neutron microscopy and neutron/gamma ray tomography.

One use of neutron emitters is the detection of light nuclei, particularly the hydrogen found in water molecules. When a fast neutron collides with a light nucleus, it loses a large fraction of its energy. By measuring the rate at which slow neutrons return to the probe after reflecting off of hydrogen nuclei, a neutron probe may determine the water content in soil.

The nucleus of most atoms (all except the most common isotope of hydrogen, protium, which consists of a single proton only) consists of protons and neutrons. The number of neutrons determines the isotope of an element. (For example, the carbon-12 isotope has 6 protons and 6 neutrons, while the carbon-14 isotope has 6 protons and 8 neutrons.) Isotopes are atoms of the same element that have the same atomic number but different masses due to a different number of neutrons.

A neutron is classified as a baryon, and consists of two down quarks and one up quark.

Answer 6

Quarks - three of them one up two down.

Answer 7

Quarks. But what are quarks made of?