use scale
a millimeter
You must first decide what you want to measure about the rice grains: their length, circumference, mass, weight, volume, color, elasticity, etc.
Personally, I would measure the length of a grain of rice in millimeters.
It is not possible to give a sensible answer to the question. A square metre is a measure of area in 2-dimensional space whereas the mass of rice depends on the volume - a 3-dimensional measure - of rice. The height of the pile of rice will affect the mass of rice.
Use dry measure measuring cup.
use scale
a millimeter
You must first decide what you want to measure about the rice grains: their length, circumference, mass, weight, volume, color, elasticity, etc.
Personally, I would measure the length of a grain of rice in millimeters.
You would measure a rice plant (or perhaps the length of a rice field) in meters. You would generally measure a container of rice grains (for cooking or eating) in kilograms, unless you were concerned about how much space it would take up on a shelf or something like that.
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It is not possible to give a sensible answer to the question. A square metre is a measure of area in 2-dimensional space whereas the mass of rice depends on the volume - a 3-dimensional measure - of rice. The height of the pile of rice will affect the mass of rice.
Some recipes measure rice in cups. In 225 grams of rice there would be approximately just one cup of rice.
cooked
ounces
The volume is best measured in millilitres still. The weight is the best approach for this. To measure size i.e. width in particular, a millimetre is a good unit to use.