Convert cubic foot to teaspoon

Recipes give ingredients either by volume (millilitres, cups, spoons) or by weight (grams, ounces), and the two cannot be converted directly: the weight of a given volume depends on the ingredient. A cup of water weighs about 240 g, a cup of flour only about 125 g and a cup of sugar about 200 g. The link between the two is the density of the ingredient.

A cup is not the same size everywhere: the US customary cup is 236.6 ml (US food labels round it to 240 ml), the metric cup used in Australia, New Zealand and Canada is 250 ml, and the old imperial cup was 284 ml, half an imperial pint. A tablespoon is 15 ml in the US, UK and Europe but 20 ml in Australia; a teaspoon is 5 ml. The fluid ounce here is the 30 ml of nutrition labels; the US fluid ounce is strictly 29.57 ml and the imperial one 28.41 ml.

American refrigerators are rated in cubic feet (a 20 cu ft fridge holds about 570 l, and 1 cu ft is 28.3 l), natural gas is metered in hundreds of cubic feet (ccf) and billed in therms, and lorries and moving boxes are sized in cubic feet. Concrete, gravel, mulch and topsoil are ordered by the cubic yard, 27 cu ft or 0.76 m³: 'a yard of concrete'. The cubic inch, 16.4 cm³, is how classic American engines are sized: a 350 cu in V8 is a 5.7-litre engine.