Detailed spatial and temporal measurements of the total vector electric field E and current density J in a plasma with dynamic magnetic field line reconnection have been made. The resistivity calculated via the generalized Ohm's law is found to be spatially inhomogeneous with values exceeding in classical resistivity by 1 to 2 orders of magnitude. Resistivity and current density do not maximize in the same locations. The dissipation E⋅J is determined and analyzed in terms of particle heating and fluid acceleration. Electron heating is found to be the dominant dissipation process in the diffusion region. Independent measurements of the divergence of the Poynting vector ∇⋅(E¿H), the change in stored magnetic field energy ∂/∂t(B2/2&mgr;0), and the dissipation give a consistent, detailed picture of the energy flow. Efficient conversion of electromagnetic energy into particle heating is observed.