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  2. Scientific method - Wikipedia

    en.wikipedia.org/wiki/Scientific_method

    The history of scientific method considers changes in the methodology of scientific inquiry, not the history of science itself. The development of rules for scientific reasoning has not been straightforward; scientific method has been the subject of intense and recurring debate throughout the history of science, and eminent natural philosophers and scientists have argued for the primacy of ...

  3. Gravimetric analysis - Wikipedia

    en.wikipedia.org/wiki/Gravimetric_analysis

    Gravimetric analysis describes a set of methods used in analytical chemistry for the quantitative determination of an analyte (the ion being analyzed) based on its mass. The principle of this type of analysis is that once an ion's mass has been determined as a unique compound, that known measurement can then be used to determine the same analyte's mass in a mixture, as long as the relative ...

  4. Abiogenesis - Wikipedia

    en.wikipedia.org/wiki/Abiogenesis

    The research reported by Martin in 2016 supports the thesis that life arose at hydrothermal vents, [224] [225] that spontaneous chemistry in the Earth's crust driven by rock–water interactions at disequilibrium thermodynamically underpinned life's origin [226] [227] and that the founding lineages of the archaea and bacteria were H 2-dependent ...

  5. History of chemistry - Wikipedia

    en.wikipedia.org/wiki/History_of_chemistry

    Chemistry. The 1871 periodic table constructed by Dmitri Mendeleev. The periodic table is one of the most potent icons in science, lying at the core of chemistry and embodying the most fundamental principles of the field. The history of chemistry represents a time span from ancient history to the present.

  6. Biogeochemical cycle - Wikipedia

    en.wikipedia.org/wiki/Biogeochemical_cycle

    A biogeochemical cycle, or more generally a cycle of matter, [1] is the movement and transformation of chemical elements and compounds between living organisms, the atmosphere, and the Earth's crust. Major biogeochemical cycles include the carbon cycle, the nitrogen cycle and the water cycle. In each cycle, the chemical element or molecule is ...

  7. Composition of the human body - Wikipedia

    en.wikipedia.org/wiki/Composition_of_the_human_body

    About 99% of the mass of the human body is made up of six elements: oxygen, carbon, hydrogen, nitrogen, calcium, and phosphorus. Only about 0.85% is composed of another five elements: potassium, sulfur, sodium, chlorine, and magnesium. All 11 are necessary for life. The remaining elements are trace elements, of which more than a dozen are ...

  8. Genetic engineering - Wikipedia

    en.wikipedia.org/wiki/Genetic_engineering

    This is an accepted version of this page This is the latest accepted revision, reviewed on 5 November 2024. Manipulation of an organism's genome For a non-technical introduction to the topic of genetics, see Introduction to genetics. For the song by Orchestral Manoeuvres in the Dark, see Genetic Engineering (song). For the Montreal hardcore band, see Genetic Control. Part of a series on ...

  9. Law of definite proportions - Wikipedia

    en.wikipedia.org/wiki/Law_of_definite_proportions

    The law of definite proportion was given by Joseph Proust in 1797. [2]I shall conclude by deducing from these experiments the principle I have established at the commencement of this memoir, viz. that iron like many other metals is subject to the law of nature which presides at every true combination, that is to say, that it unites with two constant proportions of oxygen.