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[1] [2] Not all electromagnets use cores, so this is called a ferromagnetic-core or iron-core electromagnet. This phenomenon occurs because the magnetic core's material (often iron or steel) is composed of small regions called magnetic domains that act like tiny magnets (see ferromagnetism). Before the current in the electromagnet is turned on ...
1742 — Anders Celsius proposed a temperature scale in which 100 represented the temperature of melting ice and 0 represented the boiling point of water at 25 inches and 3 lines of barometric mercury height. [8] This corresponds to 751.16 mm, [9] so that on the present-day definition, this boiling point is 99.67 degrees Celsius. [10]
Water at the top of the troposphere, particularly in liquid and solid states, cools as it emits net photons to space. Neighboring gas molecules other than water (e.g. nitrogen) are cooled by passing their heat kinetically to the water. This is why temperatures at the top of the troposphere (known as the tropopause) are about -50 degrees Celsius.
The main feature of thermodynamic diagrams is the equivalence between the area in the diagram and energy. When air changes pressure and temperature during a process and prescribes a closed curve within the diagram the area enclosed by this curve is proportional to the energy which has been gained or released by the air.
The pressure on a pressure-temperature diagram (such as the water phase diagram shown above) is the partial pressure of the substance in question. A phase diagram in physical chemistry , engineering , mineralogy , and materials science is a type of chart used to show conditions (pressure, temperature, etc.) at which thermodynamically distinct ...
In synthetic chemistry, a combined magnetic stirrer/heater, equipped with a built-in temperature control mechanism and temperature probe, is commonly used with a heating bath (commonly oil, sand, or low-melting metal) or cooling bath (commonly water, ice, or an organic liquid mixed with liquid nitrogen or dry ice as coolant), allowing reactions ...
The temperature increases towards the center of the Earth, and the higher temperature of the fluid lower down makes it buoyant. This buoyancy is enhanced by chemical separation: As the core cools, some of the molten iron solidifies and is plated to the inner core. In the process, lighter elements are left behind in the fluid, making it lighter.
The ICAO defines the International Standard Atmosphere, which is the model of the standard variation of pressure, temperature, density, and viscosity with altitude in the Earth's atmosphere, and is used to reduce a station pressure to sea level pressure. Airport observations can be transmitted worldwide through the use of the METAR observing code.