Dehydration is the excessive loss of fluids in the body. Low levels of calcium and potassium may also cause muscle cramps, since both minerals contribute to healthy muscle function. Low blood supply to your legs and feet can cause cramping in those areas when you exercise, walk, or participate in physical activities.
Physical properties of materials and systems can often be categorized as being either intensive or extensive quantities, according to how the property changes when the size (or extent) of the system changes. According to IUPAC, an intensive property is one whose magnitude is independent of the size of the system.
A physical property of a pure substance is anything that can be observed without changing the identity (that is, the chemical nature) of the substance. The obervations usually consist of some type of numerical measurement, although sometimes there is a more qualitative (non-numerical) description of the property.