A method and apparatus for reporting dynamic properties of a product using radio frequency identification device technology. With this invention, an electronic tag is equipped with a sensor which determines dynamic properties of a product when the tag is activated. The dynamic properties of the product are then either further processed into other dynamic properties. In any event either the former or the latter dynamic properties are then transmitted from the tag. Such dynamic properties could be the temperature of a product or the expiration date of the product derived from periodic measurements of the temperature of the product.