Machines were used for many purposes by both the Aztecs and the Spanish when when they needed to transfer energy into motion, or move materials in a controlled way. in learning about mechanical devices, students will investigate how components are linked so that energy is transferred efficiently and desired functions are performed. A comparison of past and present technologies will help students recognize that different approaches have been used over time to meet common needs. Evaluation of efficiency, effectiveness and impacts within the Spanish conquest of Mexico will be the focal point for investigation and experimentation.