This paper describes the Trusted Tiny Things project which is investigating some of the challenges inherit in making the Internet of Things (IoT) more transparent to users. We present a semantic framework for reasoning about the capabilities of IoT devices based on provenance information collected from devices and their associated services. As part of this framework we have developed a semantic model, services and a smartphone app to represent, store and query IoT provenance. The semantic model and app was informed via a series of participatory design activities with users. In this paper we discuss the use of the system with two distinct IoT devices: an NFC tag used at bus stops to provide a means to access real-time bus timetables, and a black-box device installed into vehicles by insurance companies to track driving behaviour.