Considerable research has focused on securing SCADA systems and protocols, but an efficient approach for conducting experiments that measure the impact of attacks on the cyber and physical components of the critical infrastructure is not yet available. This paper attempts to address the issue by presenting an innovative experimental framework that incorporates cyber and physical systems. An emulation testbed based on Emulab is used to model cyber components while a soft real-time simulator based on Simulink is used to model physical processes. The feasibility and performance of the prototype is evaluated through a series of experiments. The prototype supports experimentation with networked industrial control systems and helps understand and measure the consequences of cyber attacks on physical processes.