When the beta is the expansion coefficient according to the area of the object is changed, per unit area and per degree area of the temperature of an object change. Units per degree
When a beta coefficient of expansion, according to the area of the object is the same per unit area and per degree of temperature of the object to be measured in degrees.
When the beta's coefficient of expansion by area of objects is the area change ไปต่อห one original and one per unit area of the object at the degree of temperature change. The unit has a per degree.