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  2. Matter - Wikipedia

    en.wikipedia.org/wiki/Matter

    Fully 70% of the matter density in the universe appears to be in the form of dark energy. Twenty-six percent is dark matter. Only 4% is ordinary matter. So less than 1 part in 20 is made out of matter we have observed experimentally or described in the standard model of particle physics. Of the other 96%, apart from the properties just ...

  3. State of matter - Wikipedia

    en.wikipedia.org/wiki/State_of_matter

    In regular cold matter, quarks, fundamental particles of nuclear matter, are confined by the strong force into hadrons that consist of 2–4 quarks, such as protons and neutrons. Quark matter or quantum chromodynamical (QCD) matter is a group of phases where the strong force is overcome and quarks are deconfined and free to move.

  4. AP Chemistry - Wikipedia

    en.wikipedia.org/wiki/AP_Chemistry

    The 2014 AP Chemistry exam was the first administration of a redesigned test as a result of a redesigning of the AP Chemistry course. The exam format is now different from the previous years, with 60 multiple choice questions (now with only four answer choices per question), 3 long free response questions, and 4 short free response questions.

  5. List of states of matter - Wikipedia

    en.wikipedia.org/wiki/List_of_states_of_matter

    Metallic and insulating states of materials can be considered as different quantum phases of matter connected by a metal-insulator transition. Materials can be classified by the structure of their Fermi surface and zero-temperature dc conductivity as follows: [4] Metal: Fermi liquid: a metal with well-defined quasiparticle states at the Fermi ...

  6. Spectroscopy - Wikipedia

    en.wikipedia.org/wiki/Spectroscopy

    Spectroscopy, primarily in the electromagnetic spectrum, is a fundamental exploratory tool in the fields of astronomy, chemistry, materials science, and physics, allowing the composition, physical structure and electronic structure of matter to be investigated at the atomic, molecular and macro scale, and over astronomical distances.

  7. Standard Model - Wikipedia

    en.wikipedia.org/wiki/Standard_Model

    Mathematical consistency of the Standard Model requires that any mechanism capable of generating the masses of elementary particles must become visible [clarification needed] at energies above 1.4 TeV; [45] therefore, the LHC (designed to collide two 7 TeV proton beams) was built to answer the question of whether the Higgs boson actually exists ...

  8. Crystal structure - Wikipedia

    en.wikipedia.org/wiki/Crystal_structure

    In crystallography, crystal structure is a description of ordered arrangement of atoms, ions, or molecules in a crystalline material. [1] Ordered structures occur from intrinsic nature of constituent particles to form symmetric patterns that repeat along the principal directions of three-dimensional space in matter.

  9. Chemical element - Wikipedia

    en.wikipedia.org/wiki/Chemical_element

    Only about 4% of the total mass of the universe is made of atoms or ions, and thus represented by elements. This fraction is about 15% of the total matter, with the remainder of the matter (85%) being dark matter. The nature of dark matter is unknown, but it is not composed of atoms of elements because it contains no protons, neutrons, or ...