Conversion from 3 Nanoliters to US Dry pints

Information about the Nanoliter (nL)

The nanolitre is a unit of volume equal to one billionth of a litre, written nL. It is a thousandth of a microlitre, and a nanolitre of water has a mass of one microgram. It is the scale at which liquid handling stops being a matter of pipettes and becomes a matter of engineered channels, printed droplets and acoustic pulses.

Microfluidics is built here. A lab-on-a-chip moves samples through channels a few tens of micrometres wide, so the volume inside any one segment is measured in nanolitres, and a whole analysis may consume less than a microlitre. Working at this scale changes the physics as well as the quantity: surface tension dominates gravity, flows stay orderly rather than turbulent, and mixing has to be engineered rather than assumed.

Digital polymerase chain reaction shows what the scale buys. A sample is divided into around twenty thousand droplets of roughly one nanolitre each, every droplet is amplified separately, and the number that come out positive gives an absolute count of target molecules rather than a relative measurement. Dividing a microlitre into thousands of countable compartments is only possible because a nanolitre is small enough to hold either one target molecule or none.

Drug screening moves liquid without touching it. Acoustic dispensers use a focused sound pulse to eject droplets of two and a half nanolitres from an open well, with no tip and therefore no cross-contamination and no plastic waste. A screening plate of fifteen hundred wells can be filled with distinct compounds in a few minutes at this volume.

Printing and spotting work at the same magnitude. A microarray spot holds between half a nanolitre and five, an inkjet droplet is a few picolitres so a nanolitre is several hundred drops, and single-cell platforms encapsulate individual cells in droplets of this size because a mammalian cell occupies only a few picolitres.

Handling nanolitres reliably is mostly a fight against evaporation. A one-nanolitre droplet exposed to air can lose a measurable fraction of itself in seconds, so devices at this scale work under oil, in sealed channels or in humidity-controlled enclosures, and that constraint shapes the instruments more than the dispensing itself does.

One nanolitre equals 0.001 microlitres, 0.000001 millilitres, 0.001 cubic millimetres, or 1,000,000 cubic micrometres.

Information about the US Dry pint (pt)

The United States dry pint is a unit of volume equal to 550.610471 millilitres, or 33.6 cubic inches. Its symbol is pt. It belongs to a separate American measuring system used for produce and grain rather than for liquids, and it is about sixteen per cent larger than the United States liquid pint of 473 millilitres.

Two parallel chains exist because two kinds of goods were once measured differently. Liquids descend from the wine gallon of 231 cubic inches, while dry goods descend from the Winchester bushel of 2150.42 cubic inches, a corn measure standardised in medieval England. Dividing the bushel by four gives a peck, by thirty-two a dry quart, and by sixty-four a dry pint, and none of those figures has any relation to the liquid chain.

Berries are where the unit is still met. Blueberries, raspberries and strawberries are sold in American markets in pint and quart baskets, and the basket is a dry measure. A pint of blueberries is therefore 551 millilitres of fruit, not 473, and a shopper comparing that basket with a pint of cream is comparing two different quantities under one name.

Nothing on a label resolves the ambiguity. Both are written pt, both are called a pint, and the word gives no clue as to which chain is meant. In practice the contents decide: if it pours, it is liquid measure, and if it is heaped, it is dry. That rule is reliable but it is nowhere written down, which is why converted American recipes so often disagree with one another.

Its existence is a survival from selling by bulk. Before cheap accurate scales, grain, apples, potatoes and shellfish were sold by filling a stamped measure and levelling it off, and the whole dry chain from bushel down to pint served that trade. Almost all of it has now been replaced by weight, and United States produce regulations increasingly specify pounds instead.

For conversion, the safest approach is to abandon the name entirely. A dry pint is 551 millilitres, a dry quart 1101, a peck 8.81 litres and a bushel 35.24. Writing the metric figure removes an ambiguity that the English word carries and cannot shed.

One United States dry pint equals 550.61 millilitres, 33.6 cubic inches, half a US dry quart, or about 1.164 US liquid pints.