Since wireless sensor motes usually have a limited source of energy, it is important to know the amount of energy consumed by different components on them while undergoing various operations. In this work, we perform some measurements to estimate the energy consumption and execution time of different operations on a Tmote Sky sensor mote. To make the measurements, different configurations are explored and the best one is set up to get precise data. For the transceiver, we discover the overhead of channel acquisition, header and footer of data frame, and transfer reliability during packet transmission. Using this data, we set up a linear equation to estimate the power consumed during every packet transmission. We then input this per-packet power consumption in a mathematical model which estimates the lower and upper bounds of routings in the network. We also categorize different simulators currently available in order to propose the function and structure of a new potential simulator. We measure energy consumptions in different power states of the microcontroller and also compute the energy and time needed to read/write data from/to the external flash memory of Tmote Sky.