what is matter?

Answer 1

Matter is the substance of which physical objects are composed. It constitutes the observable universe. There is a tendency to regard manifestations of energy, such as light and sound, as not being material. However in physics the distinction is difficult to enforce — according to the theory of relativity matter and energy can be converted into one another. Matter is said to have mass and to occupy space, but there are technical problems in physics with both criteria.

Answer 2

Matter is the substance of which physical objects are composed. It constitutes the observable universe. There is a tendency to regard manifestations of energy, such as light and sound, as not being material . However in physics the distinction is difficult to enforce — according to the theory of relativity matter and energy can be converted into one another. Matter is said to have mass and to occupy space, but there are technical problems in physics with both criteria.

In Aristotle's philosophy, matter constitutes the substratum of all things, which endures through changes in form. Other philosophers preferred the millennia-old atomic theory. For Descartes, matter is principally characterized by extension: the occupancy of space. During the eighteenth century, impenetrability, "or what Leibniz used to call 'antitypy,'" was the requisite property of matter. In modern physics, the concepts of fields had taken priority over the impenetrability property of matter

Answer 3

Those answers simply quoting the Wiki definition are, of course correct. But I don't think the definition really tells us what matter really is...or at least, what it really means in the context of physics.

According to E = mc^2, there are but matter (m) and energy (E) in the universe. In fact, one is the equivalent of the other. So, when you ask, "what is matter," you are really asking what is the difference between energy and mass?

Matter is anything that has inertial rest mass (m0). And because it has inertial rest mass, its effective mass (m(v)) under velocity v can be found by m(v) = m0/L(v); where L(v) = sqrt(1 - (v/c)^2) and c = speed of light in the medium the rest mass is traveling in (e.g., space). L(v) is the Lorentz transformation found in relativity equations.

Because matter has inertia (whereas energy does not*), we can write p = m0v, which is momentum. And, in this form, we can see that matter follows Newton's three laws of motion.

For example, dp/dt = d(m0v)/dt = m0dv/dt = m0a = f = net force is one of Newt's laws. By rearranging, we have dv/dt = f/m0, which says the only way an inertial rest mass m0 can change its velocity (dv/dt) is through an applied net force f to the mass. That's another of Newt's laws. It is, in fact, his law of inertia, which is why matter (m0) is called "inertial" rest mass.

And finally, f = m0a = 0; so that a = 0, which says the sum of all forces on a mass not accelerating (v = constant) must be zero. In other words, there must be equal and opposite forces on that mass. And, there you have it, the last of Newt's laws. If the thing you have follows these laws, then it's matter (i.e., rest mass).

One other differential beween energy and mass...gravity. The force of gravity in Newt's own words is F = GmM/R^2 between two rest masses m and M. So mass, not energy, produces the force of gravity...maybe. That, at least, is the classical physics interpretation.

Relativity says that gravity bends space (not the stuff in space, but space itself). But what is not clear to me is whether gravity bends space or bent space causes the effects we attribute to gravity. It's a matter (pun intended) of cause and effect.

In any case, matter is somehow associated with the source of gravity; while energy is not. Don't get me wrong, in classical physics, energy can certainly be the result of gravity, but not its source.

For example, PE = mgh is the potential energy of a mass m raised to a height h under gravitational acceleration g. Note that mg is sometimes called weight, a force; so PE is just a force times a distance. And force times distance = W = Fh is called the work function because it defines how much work is expended to move a mass m a distance h when gravity g is pulling on that mass.

There you have it. Matter is inertial rest mass. It is that because it follows Newt's three laws of motion and because it follows his gravitational law as well. In nonrelativistic physics, that is acheived only by matter.

*Some readers may recognize that energy does in fact have a momentum defined by p' = E/c; where E = mc^2 so that p' = mc. In fact P^2 = p'^2 + p^2; where P^2 is total momentum, but the p'^2 term becomes significant only in relativistic problems. For ordinary classical physics, where v << c, p = m0v holds because p' can be set to zero in nonrelativistic coordinates [See source.].

Answer 4

Matter is anything that takes up space and has mass. Three types of matter 1-Solid 2-Liquid 3-Gas

Answer 5

When i'm asking "What is matter" i want to know the essence of it. It appears that in things , the matter is that part which
is organized around some rule(s). Ultimately, i think that you'll have to go outside of physics for an answer to this question.

Answer 6

Colloquially and in chemistry, matter is a substance that occupies space, has mass, and is composed of atoms.Matter is what ponderable objects are made of, and consists of identifiable chemical substances. These are made of atoms, which are made of protons, neutrons, and electrons. Protons and neutrons in turn are composed of quarks. Quarks and leptons (of which electrons are one variety) are considered to be the fundamental constituents of matter.

However, one problem with this definition is that it requires matter to occupy space, when according to some models, the fundamental particles (quarks and leptons) are dimensionless points.

Another problem is that it is recognized in the Standard Model of particle physics that kinetic energy and force fields contribute most of the mass of ordinary objects. To be precise, most of the mass of an atom comes from the nucleus, the nucleus is composed of neutrons and protons, the neutrons and protons are composed of quarks and the "confinement energy" of the quarks contributes more to the mass of the neutron or proton than the sum of the masses of the individual quarks.

This being the case (that ordinary physical objects are mostly composed of fields and kinetic energy by weight), the exclusion of fields and energy from the term "matter" would require that ordinary physical objects, which is what we point to as examples of "matter", be mostly composed of things we consider examples of "non-matter."

Answer 7

matter is everything that exists that can be measured and weighed.matter can be changed during a chemical reaction but its components are constant.

Answer 8

anything that have mass and occupies space is known as matter.

Answer 9

matter is a very large condensation of energy(Enstain say with e=mc^2)... you can see my explication on my blog..
http://www.adimoga.com/ce-este-in-jurul-nostru/