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6 days ago · The molecules of a gas are in constant random motion. The temperature of the gas is related to the average kinetic energy of the molecules. The higher the temperature, the greater the average kinetic energy and so the faster the average speed of the molecules.
Oct 7, 2024 · Fire, rapid burning of combustible material with the evolution of heat and usually accompanied by flame. It is one of the human race’s essential tools, control of which helped start it on the path toward civilization. The original source of fire undoubtedly was lightning, and such fortuitously.
- The Editors of Encyclopaedia Britannica
- Fire is a rapid burning of combustible material in the presence of oxygen manifested as flames. It is usually accompanied by heat and light. Fire i...
- Evidence suggests that the earliest controlled use of fire by hominins was about 1,420,000 years ago. However, it was not until about 7000 BCE that...
- Early humans used fire to keep warm and cook their food. They also learned to use it in hunting and warfare, to kill insects, and to clear forests...
- The most widespread method of producing fire among prehistoric peoples was the friction method. Most commonly, a pointed hardwood was twirled betwe...
- Fire has been an essential element at every stage of the growth of civilization. Much of the history of technology and science might be characteriz...
Oct 3, 2024 · combustion, a chemical reaction between substances, usually including oxygen and usually accompanied by the generation of heat and light in the form of flame.
2 days ago · The substance (or substances) initially involved in a chemical reaction are called reactants or reagents. Chemical reactions are usually characterized by a chemical change, and they yield one or more products, which usually have properties different from the reactants.
Sep 27, 2024 · Gas, one of the three fundamental states of matter, with distinctly different properties from the liquid and solid states. The remarkable feature of gases is that they appear to have no structure at all. They have neither a definite size nor shape, whereas ordinary solids have both a definite size.
- Edward A. Mason
3 days ago · He had produced oxygen gas by heating mercuric oxide (HgO) and various nitrates in 1771–72. [17] [18] [9] Scheele called the gas "fire air" because it was then the only known agent to support combustion. He wrote an account of this discovery in a manuscript titled Treatise on Air and Fire, which he sent to his publisher in 1775. That document ...
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5 days ago · Matter is a general term describing any 'physical substance'. By contrast, mass is not a substance but rather a quantitative property of matter and other substances or systems; various types of mass are defined within physics – including but not limited to rest mass, inertial mass, relativistic mass, mass–energy.
