Overview: Machines are used for many purposes in our daily lives when we need to transfer energy into motion or move materials in a controlled way. In learning about mechanical devices, students investigate how components are linked so that energy is transferred efficiently and desired functions are performed. A comparison of past and present technologies helps students recognize that different approaches have been used over time to meet common needs. Evaluations of efficiency, effectiveness and impacts on daily life, the community and the environment are important considerations in this unit.
Focusing Questions: How is energy transferred in mechanical devices? How do mechanical devices provide for controlled application of energy in ways that are efficient, effective and responsible?
Key Concepts
− design and function
− systems and subsystems
− transmission of force and motion
− simple machines
− mechanical advantage, speed ratios and force ratios
− hydraulics and pneumatics
− measurement of work in joules