When ' millimetres of mercury ' or ' inches of mercury ' are quoted today, these units are not based on a physical column of mercury: they have been given precise definitions that can be expressed in terms of SI units.

When measuring liquid pressure, a loop filled with gas or a light fluid can isolate the liquids to prevent them from mixing but this can be unnecessary, for example when mercury is used as the manometer fluid to measure differential pressure of a fluid such as water.

When it melts, silicon becomes a reasonable metal with an electrical conductivity of 1. 0 – 1. 3 × 10 < sup > 4 </ sup > S • cm < sup >− 1 </ sup >, a value similar to that of liquid mercury.

When the switch is tilted in the appropriate direction, the mercury touches a set of contacts, thus completing the electrical circuit through those contacts.

When the machine is rocked or tilted in an attempt to gain a product, the mercury switch activates, sounding an alarm.

When they encountered mercury atoms in the tube, they participated in purely elastic collisions.

When the amalgam is cold it is squeezed through chamois leather to separate the superfluous mercury ; the gold, with about twice its weight of mercury, remains behind, forming a yellowish silvery mass with the consistency of butter.

When the metal to be gilded is wrought or chased, it ought to be covered with mercury before the amalgam is applied, that this may be more easily spread ; but when the surface of the metal is plain, the amalgam may be applied to it directly.

When the mercury has evaporated, which is known by the surface having entirely become of a dull yellow color, the metal must undergo other operations, by which the fine gold color is given to it.

When Bell arrived on February 26, Bell visited his lawyers and then visited examiner Wilber who told Bell that Gray's caveat showed a liquid transmitter and asked Bell for proof that the liquid transmitter idea ( described in Bell's patent application as using mercury as the liquid ) was invented by Bell.

When red mercury first appeared on the international black market 15 years ago, the supposedly top secret nuclear material was ' red ' because it came from Russia.

When the mercury reaches " Cadet School ", that's where Willy goes, and the game is over.

When introduced in the 1960s, alkaline batteries contained a small amount of toxic mercury amalgam to control side reactions at the zinc cathode.

When heated, mercury vapour is created inside the lamp, and deposited when it cools.

When that happens, up to 30 mg of mercury vapor is released into the atmosphere.

When Angel tries to help her escape, he tells her he had the pill tested, and that it contained powdered lead with trace amounts of arsenic and mercury, each of which are traditional ingredients in artistry paints linked to accidental self-poisoning.

When the current is turned on, it will initiate dissolution of the metallic mercury on the one side of the drop in the capillary and deposition on the other side of the same drop.

When glass mirrors first gained widespread usage in Europe during the 16th century, most were made of an amalgam of tin and mercury, but by the 19th century mirrors were commonly made through a process by which silver was coated onto a glass surface.

When electrical current flowed through the wire, the magnetic field of the wire created a force with the field of the permanent magnet such that the wire would rotate out of the mercury trough and interrupt the electrical circuit.

When values of temperature derived with this instrument were compared with the accepted values associated with liquid helium-4 vapor pressures, differences of about 10 and 7 millidegrees respectively were found.

When a multi-component liquid is heated, the vapor pressure of each component will rise, thus causing the total vapor pressure to rise.

When the total vapor pressure reaches the pressure surrounding the liquid, boiling occurs and liquid turns to gas throughout the bulk of the liquid.

When inhaled, its vapor has been described as " very harsh.

When the process of escape and return reaches an equilibrium, the vapor is said to be " saturated ," and no further change in either vapor pressure and density or liquid temperature will occur.

When measuring vacuum, the working liquid may evaporate and contaminate the vacuum if its vapor pressure is too high.

When the air reaches a high altitude, where the temperature is low, water vapor condenses into clouds, which rain onto the Earth's surface, completing the water cycle.

When this is true, the two phases will be in equilibrium, and the gas pressure will equal the equilibrium vapor pressure of the liquid ( or solid ).

When UF < sub > 6 </ sub > is exposed to water vapor in the air, it reacts with the moisture to produce UO < sub > 2 </ sub > F < sub > 2 </ sub > ( uranyl fluoride ), a solid, and HF ( hydrogen fluoride ), a gas, both of which are highly soluble and toxic.

When heat radiates from the surface of the earth, it is released as long-wave radiation, which can move freely through gases composed of diatomic molecules ( such as the atmosphere's oxygen and nitrogen ), but is readily absorbed by triatomic molecules, such as carbon dioxide and water vapor.

When this process takes place just above the freezing level, the vapor tends to condense into supercooled water droplets, which with additional lifting and growth in size, can eventually turn into freezing rain.

When water vapor and clouds are considered together, the contribution is 66 % to 85 %.

When surface temperature drops, eventually reaching the dew point, atmospheric water vapor condenses to form small droplets on the surface.

When the ice warms and sublimates, the vapor can drag along dust, sand, and pebbles.

When the air is saturated with water vapor ( at its dew point ), the moist adiabatic lapse rate ( MALR ) or saturated adiabatic lapse rate ( SALR ) applies.

When a statement of the conservation of water vapor substance is included, these six equations form the basis for any numerical weather prediction scheme.

When the pressure within the liquid drops to below the liquid's vapor pressure, tiny vapor bubbles can begin to form at the high point and the siphon effect will end.

When the transferred image was brought into proximity with the vapor from the evaporating liquid the result was a perfectly fixed copy without any of the distortion or toner migration which can occur with the other methods.

When the air is clear and relatively free of aerosols, blue or white light ( for example from metal halide lamps, fluorescent lamps, and white light-emitting diodes ) contributes significantly more to sky-glow than an equal amount of yellow light ( for example from high-and low-pressure sodium vapor lamps ).

When moisture content is a mechanism for product degradation, packaging with a low moisture vapor transmission rate and the use of desiccants help keep the moisture in the package within acceptable limits.

When these components are added to the mixture, it forms a heterogeneous azeotropic mixture in vapor-liquid-liquid equilibrium, which when distilled produces anhydrous ethanol in the column bottom, and a vapor mixture of water and cyclohexane / benzene.

When vapor pressure is below 45 kPa starting a cold engine becomes difficult.