A mobile sensing system, comprising: a sensing device (620, 100A) for measuring a thermal property of an object, comprising: an RF circuit and an antenna electronically coupled to the RF circuit, a sensor electronically coupled to the RF circuit, and a thermal source thermally coupled to the sensor and electronically coupled to the RF circuit, a thermal spreader (115, 230, 330, 350) having a first major surface and a second opposing major surface, such that when the sensing device is in use, the thermal spreader is in thermal contact with the object and the first major surface is proximate to the object, and the thermal source is disposed proximate to the second major surface, the thermal source generates a substantially uniform thermal flux on the first major surface of the thermal spreader, a mobile device having a processor, and an RF reader connected to or integrated with the mobile device, wherein the RF reader is configured to interrogate the sensing device; wherein the sensing device is configured to receive power when the RF reader interrogates the sensing device and provides at least a portion of the power to the thermal source, wherein the sensor is configured to generate a series of sensing signals associated with temperature when the thermal source is powered, wherein the sensing device is configured to transmit a series of data signals associated with the series of sensing signals via the antenna; and wherein the RF reader is configured to receive the series of data signals and the processor is configured to determine the thermal property of the object using at least some of the series of data signals, wherein a thermal property of the object is determined based on a time variation of the series of data signals, wherein the thermal property of the object comprises at least one of a thermal conductivity of the object, a thermal diffusivity of the object, and a heat capacity of the object, wherein the thermal spreader has a known thermal property, wherein the processor is further configured to determine the thermal property of the object using the known thermal property of the thermal spreader. an RF circuit and an antenna electronically coupled to the RF circuit, a sensor electronically coupled to the RF circuit, and a thermal source thermally coupled to the sensor and electronically coupled to the RF circuit, a thermal spreader (115, 230, 330, 350) having a first major surface and a second opposing major surface, such that when the sensing device is in use, the thermal spreader is in thermal contact with the object and the first major surface is proximate to the object, and the thermal source is disposed proximate to the second major surface, the thermal source generates a substantially uniform thermal flux on the first major surface of the thermal spreader, a mobile device having a processor, and an RF reader connected to or integrated with the mobile device, wherein the RF reader is configured to interrogate the sensing device; wherein the sensing device is configured to receive power when the RF reader interrogates the sensing device and provides at least a portion of the power to the thermal source, wherein the sensor is configured to generate a series of sensing signals associated with temperature when the thermal source is powered, wherein the sensing device is configured to transmit a series of data signals associated with the series of sensing signals via the antenna; and wherein the RF reader is configured to receive the series of data signals and the processor is configured to determine the thermal property of the object using at least some of the series of data signals, wherein a thermal property of the object is determined based on a time variation of the series of data signals, wherein the thermal property of the object comprises at least one of a thermal conductivity of the object, a thermal diffusivity of the object, and a heat capacity of the object, wherein the thermal spreader has a known thermal property, wherein the processor is further configured to determine the thermal property of the object using the known thermal property of the thermal spreader.