Grain: The grain is a unit of mass primarily used for measuring the weight of small objects or quantities, especially in the context of bullets, ammunition, and some food products. One grain is approximately equal to 0.0648 grams.
A femtogram (fg) is a metric unit of mass in the International System of Units (SI). It represents one quadrillionth of a gram or 10^-15 grams. The metric system is a decimal-based system of measurement used worldwide, and it is particularly useful for expressing extremely small quantities of mass.
To provide context for the size of a femtogram:
Femtograms are primarily used in advanced scientific and technical fields, particularly in situations where measuring the tiniest quantities of substances or particles is critical. Some common applications of femtograms include: