The term matter traditionally refers to the substance that all objects are made of.[1][2] One common way to identify this "substance" is through its physical properties; a common definition of matter is anything that has mass and occupies a volume.[3] However, this definition has to be revised in light of quantum mechanics, where the concept of "having mass", and "occupying space" are not as well-defined as in everyday life. A more general view is that bodies are made of several substances, and the properties of matter (among them, mass and volume) are determined not only by the substances themselves, but by how they interact. In other words, matter is made up of interacting "building blocks",[4][5] the so-called particulate theory of matter.[6]
The concept of matter has been refined many times in history, in light of the improvement in knowledge of just what the basic building blocks are, and in how they interact. For example, in the early 18th century, Isaac Newton viewed matter as "solid, massy, hard, impenetrable, movable particles", which were "even so very hard as never to wear or break in pieces"[7] The "primary" properties of matter were amenable to mathematical description, unlike "secondary" qualities such as color or taste.[7] In the 19th century, following the development of the periodic table, and of atomic theory, atoms were seen as the being the fundamental constituents of matter; atoms formed molecules and compounds.[8]
In the late 19th century with the discovery of the electron, and in the early 20th century, with the discovery of the atomic nucleus, and the birth of particle physics, matter was seen as made up of electrons, protons and neutrons interacting to form atoms. Today, we know that even protons and neutrons are not indivisible, they can be divided into quarks, while electrons are part of a particle family called leptons. Both quarks and leptons are elementary particles, and are currently seen as being more fundamental constituents of matter.[9]
These quarks and leptons interact through four fundamental forces: gravity, electromagnetism, weak interactions, and strong interactions. The Standard Model of particle physics is currently the best explanation for all of physics, but despite decades of efforts, gravity cannot yet be accounted for at the quantum-level; it is only described by classical physics (see quantum gravity and graviton).[10] Interactions between quarks and leptons are the result of an exchange of force-carrying particles (such as photons) between quarks and leptons.[11] The force-carrying particles are not themselves building blocks. As one consequence, mass and energy cannot always be related to matter. For example, the carriers of the electric force (photons) possess energy (see Planck relation) and the carriers of the weak force (W bosons) are massive, but neither are considered matter either.[12] However, while these particles are not considered matter, they do contribute to the total mass of atoms or subatomic particles.[13][14]
Matter is commonly said to exist in four states (or phases): solid, liquid, gas and plasma. However, advances in experimental technique have realized other phases, previously only theoretical constructs, such as Bose–Einstein condensates and Fermionic condensates. A focus on an elementary-particle view of matter also leads to new phases of matter, such as the quark-gluon plasma.[15]
In physics and chemistry, matter exhibits both wave-like and particle-like properties, the so-called wave-particle duality.[16][17][18]
In the realm of cosmology, extensions of the term matter are invoked to include dark matter and dark energy, concepts introduced to explain some odd phenomena of the observable universe, such as the galactic rotation curve. These exotic forms of "matter" do not refer to matter as "building blocks", but rather to currently poorly-understood forms of mass and energy.[19]
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The Daily News of Newburyport
With homework, tests and pop quizzes, school can be a pain in the neck for some students. But recently, with students toting more and more textbooks and ...
Sam Gustin
Fri, 28 Aug 2009 18:25:00 GM
A source with knowledge of the . matter. called Terzano's statement a "non-denial denial," saying, "This is an attempt to obfuscate the fact that they are indeed having 'screw Google' meetings." Microsoft is working to allay Justice ...
Q. I have no friends and my family not friendly to me - so went people ask me - How by not telling much about your personal matter and talking something else - how do you do that? Surely people will dislike by not telling them. They will ask me why you are eating home food or why are you walking home or why you have no friends?
Asked by Simon Bernard - Mon Sep 8 03:40:28 2008 - - 3 Answers - 0 Comments
A. Most people like to talk about themselves. If you learn to become a good listener people will want to be with you. Often when you are asked a question you can avoid answering it by asking the same question. For example, if somebody asked you what was your opinion of a particular TV show, you could respond by saying "That's an interesting question, what did you think of it?" You have turned the question around and avoided having to give your opinion. If somebody inquires about your family you could reply by saying "That's coincidental, I was just about to ask you the same question, are both your parents well?"
Answered by Clive L - Mon Sep 8 03:55:59 2008
