the m number on a pint glass means milk.
the m number on a pint glass means milk.
what does the m number mean on a pint glass?
milk
the imperial pint (≈ 568 ml) is used in the united kingdom and ireland and to a limited extent in commonwealth nations. in the united states, two pints are used: a liquid pint (≈ 473 ml) and a less-common dry pint (≈ 551 ml). each of these pints is one-eighth of its respective gallon, but the gallons differ. this difference dates back to 1824, when the british weights and measures act standardised various liquid measures throughout the british empire, while the united states continued to use the earlier english measure. the imperial pint consists of 20 imperial fluid ounces and the us liquid pint is 16 us fluid ounces, making the imperial fluid ounce about 4% smaller than the us fluid ounce.
pint
when a gas is heated, its volume increases. it will displace cooler gases as it expands. if this is done in a partially enclosed space, and the vessel allowed to be full of hot gas, when the heat is taken away, the gases cool and as they do, the amount of liquids that the gas can hold will decrease. therefore, most of the moisture and alcohol held in the gas will condense. as the gas cools, it decreases in volume, and the pressure drops. thus when the flaming alcohol in a backdraft is covered with a pint glass over a saucer, the dense, cold air is replaced with less dense, warm air with a lot of alcohol vapour held in it. as the oxygen flow to the fire is restricted, the remaining oxygen is used up and the fire in the pint glass goes out, removing the heat source. the alcohol-laden warm air now in the glass cools and begins to create a pressure difference. the air outside the pint glass forces its way into the partially evacuated pint glass and is responsible for pushing any liquid at the outside bottom of the pint glass further inside (as the seal of the glass and the saucer is not perfect) as it begins to equalise the pressure difference. once the majority of the liquid is inside the upside down pint glass, sometimes further air can be seen to bubble up into the glass. at some point an equilibrium will occur, where the pressure difference between inside and outside of the glass is equal to the pressure of the column of liquid held up inside, and this will hold the liquid inside the glass. sometimes, when a good seal is made, the pressure difference between the inside and the outside of the glass exerts a great enough force that when the glass is lifted, the saucer will remain stuck to its underside.
backdraft (drink)